The Battery FAQ
By Hombre sin Nombre, Flash #412
Compiled & edited by Kristian #562
Updated by Scott, ID #1244
Please read the Disclaimer before attempting any work in
Last Updated: 13 June 2007, by Winter #1935
- Battery List / Battery Selection Questions
- Modifications and Installation
- General Questions
- Battery Maintenance
- My Battery seems to be low on water. What shall I fill it with?
- What about that Acid in a Bottle? If a battery is low on water, why can't battery acid be added instead of water?
- How do I put water in those Tiny Holes?
- Can I add water with the battery still connected?
- While doing my routine 1000 mile battery top off, I was surprised to find several cells almost dry. This is unusual. Whats happening?
- What about more details of Battery Maintenance?
- What about the Battery Overflow Tube?
- Can you (safely) add water to a charging battery?
- How do I clean up acid spills?
- GS battery check - can it really be that difficult?
- How do I remove the battery from my CS?
- Should I grease the battery terminals?
- What if I overfill my battery?
- Battery Charging
- I bought a new battery. I need to charge it up. What current should I use?
- Can I charge it through the Accessory Plug?
- How long should it normally take to charge the battery on a Battery Tender?
- I fiddle with electronics. Is there a Battery charger schematic anywhere?
- My Battery Water is always Low. I suspect the VR is overcharging the System. Is there a solution?
- Can I start a Motorbike with a Flat Battery using a Car Battery?
- Adding water to battery. I noticed my battery ('99F) was near the low line. Should I ride for an hour, or so, to charge up the newly diluted battery acid, or can the bike sit overnight or for a day or two?
- How do I use a Voltmeter?
- Do you have any more information on the F's Charging system?
- What is best way to make Battery Charging Access?
- Do I have to disconnect any battery wires to charge it?
- Can I jump start my bike?
- Is it okay to charge the battery on a GS/Dakar/CS bike (with an FI computer)?
- Does an AGM battery need a battery tender?
- Do I need to remove the little caps off the cells when charging the battery?
- Battery never fully charged?
- Can the battery system handle a 500mA AA battery charger?
- Can I charge my iPod overnight from the bike?
- Battery Tenders
- Battery Problems
- Is it true to say the Voltage Regulator (VR) will be stressed and eventually fail if the battery is not kept topped up?
- Is the converse also true that a failing VR will empty the battery?
- Can I disconnect the battery while the bike is running?
- When I try to start my bike there is a Tic Tic Tic sound coming from the Solenoid, (Large Round Object just Rear of the Battery)
- My bike will not start. When I turn the key to the on position, there is a buzzing sound.
- I'm having problems starting the bike. Could it be the Battery?
- My ABS light came on while riding and stayed on. Now the bike won't start!
- Stalling, difficulty starting and hesitation when applying generous throttle?
- Can a battery get too weak to start after only 12 days of non use except for a quick 10 sec. start to move to from the driveway to garage?
- If I've allowed my Battery to Drain Water/Get Low (Due to e.g. VR Problems, Poor Maintenance), will it ever fully recover?
- Ever heard of a sudden battery failure? Sudden Battery Death? Battery Suddenly Died?
- Pop! Smoke! Dead Dakar! - (battery area - anybody had it happen?)
- Is it possible for a brand new battery to go bad, or might there be another reason like a short somewhere?
- My bike is dead (no headlight, brakelight etc), but multimeter shows the battery is good.
- What are the normal voltages of the battery?
- Battery life when riding short distances?
- Can a battery tender "boil off" a wet cell battery?
- What would cause the battery to bulge?
- Do I need to do the Flay to keep my new battery in good condition?
- Can I remove my battery while the bike is running?
- GS clock reads funny when inserting a new battery?
- Getting Home With a Dead Battery
- Battery Life
- External Battery Links
- Battery Guages? See the Aftermarket Voltmeter FAQ
For other related FAQs:
Batteries are our friends. The design engineers cleverly put the
battery right behind the hot engine and catalytic converter (on the
Classic); and above the engine and next to the oil reservoir (on the GS).
Toasty batteries are prone to drying out, so please check your 12 volt
friend often, especially in the summer. It also noted that a dry battery
is causing voltage regulators to go bad. Another good reason to check them
often before they not only get the regulator but perhaps also the
|I'm Confused! My Battery Has Died, What Should I get?|
This is the short version of the FAQ... You can get a OEM
replacement from most online battery sites, or most places that store a
good variety of batteries. Just look for the YB12AL-A battery.
Many people also replace their OEM battery with an Absorbed Glass Matt
(AGM) battery. There are two problems with the OEM battery. Firstly you
need to check the water level regularly, and this can be a pain
(especially on the GS/Dakar models). Secondly if you drop your bike, or
the overflow tube comes loose, there is a chance acid will spill over
parts of the bike and cause more problems.
The tables at the top of this FAQ list alternative batteries, and the
experiences people have had with them. You will also find for each battery
it tells you any specific modifications you may need to make.
|Drop-In AGM is now available|
BikeBatts in the US now offer a drop-in AGM battery - in other words
no modifications to the bike are required. You will want to call Tim to ask
for the battery. Unfortunately BikeBatts will not tell anyone where they
get the battery (other than China), so we can not identify a supplier for
other countries. We have no further details on this battery.
Note: This is not a YB12AL-A2 AGM battery, and it is not clear
if it is an AGM battery or not (it may be a SLA). There is very little
information on the specs of this battery.
This battery should fit in all F650 models including Classic, GS, Dakar and CS models. It is unknown what battery the G650X uses.
|Warning: Check and Re-check the +ve and -ve Terminals!|
When connecting a new battery, check and then recheck your
battery terminals for the positive and negative polarities.
Make sure they are around the right way. This is what happens when you
I am so stoopid. I hadn't started my 02 GS in months, so the
battery was dead. Went and got one that fit, came home, griped about
German over-engineering the entire time I spent undoing all the stupid
torx screws, and then fitted the new battery. 1.2 seconds after I
connected it, smoke started pouring from the wiring harness. I freaked out
and grabbed the fire extinguisher and gave it a squeeze. An anemic little
trickle came out even though the gauge read full. Do I get to watch my
bike burn to the ground?
After a few minutes, the smoke had stopped and I grabbed
the screwdriver and disconnected the battery. It was then that I realized
that the - and + terminals were on different sides from the stock battery.
In one fell swoop, I turned my $6000 dollar motorcycle into a worthless
pile of parts. I cried, I screamed dirty words at the heavens, I prayed to
wake up from a nightmare. But here I am. With a 2002 F650 GS with less
than 10k miles with a melted wiring harness. I am sure I killed the
ignition too. OMG. It's something I have to have the dealer work on, and
it's probably going to cost me upwards of a grand. Perhaps I should just
sell it for parts. Sad
Moral of the Story: Check THREE TIMES before connecting the
battery. And get your fire extinguisher re-charged TODAY! Do as I say, not
as I do! clown shoes
Battery List / Battery Specific Questions
This section contains a list of batteries with links to any
modifications you may need to perform to fit the battery to your bike.
There are also some questions that are specific to batteries only, and are
not directly related to the F650.
Note 1: The 12AL-A is a common battery size and can be bought
many other places other than the dealership.
Note 2: For each battery, the top row are mm in Length,
Width, Height and kgs in Weight, and the bottom row are inchs/lbs. All
batteries listed are 12V.
Note 3: Amp/hr (AH) represents the total power stored within the
battery; CCA represents the ability to start an engine under low
temperature conditions (you could also view this as how much power can be
delivered in a very short period of time).
||$34 + shipping from tireexpress.com
BMW Part # 61212346420
||Post Connection has an Add on Clamp, but it can be used no Problem - k.)
||A conventional "spillable" battery requiring dry shipment.
Acid may be purchased locally (i.e. Sears stock #44000 @ $2.50).
|Japan Storage Battery
||Autozone for about $52 before taxes
Absorbed Glass Matt (AGM)
||See CG Battery Deal!
$50 + shipping from Batteryweb
||Will fit but can be tight in a GS
||Chang Nan Battery
Sometimes labeled BigCrank
||tray mods (method 3)
Sealed Lead Acid (SLA)
||$86 + shipping from Batterymart.com|
Enersys Reserve Power (Powersafe)
Call U.S. Energy systems, INC, 1-800-582-5028, Ask for Darlene (19 Nov 2004)
Possibly no longer available.
See the Odyssey PC310 for alternative.
|(See the Odyssey PC310)
||This is most likely the alterative to the SBS8.|
If anyone can confirm this that would be appreciated.
||A YTX12L-BS would be a better choice, it has the
terminals that would fit best. (Around the right way).
(Remove Tray AND Reverse Terminals)
|Rebranded Yuasa battery. It fits the classic shelf with
the rubber bootie and goes for about $75.
|(OEM Alternative) I replaced my original battery
(bought the bike 2/13/97) with an Interstate YTX12-BS for $70 in July
before taking my 7K trip. The only way it would fit was on its end
after removing the rubber box liner, and the wires will just reach.
The battery does, as mentioned above, hold a charge MUCH better.
Since returning from my trip on 9/20, I have ridden the bike twice -
about 3-4 weeks between rides, and when I put the smart Charger on it
day before yesterday, the needle flickered once it was apparently
fully charged. This was, incidentally, the only battery my dealer
could find at that time that would fit. Hal #15.
|DOES NOT FIT!
|??? Prob does not fit
Battery Selection Questions
Here is a tip: A good place to compare battery designations,
sizes and configurations is in the JC Whitney catalog
battery section covers this in great detail. Once you know the battery
codes that will fit your bike, you can go battery surfing, as I believe
that they all use the same codes (such as YB12AL-A). The 12 is the battery
amp hour rating. I believe the Y may indicate a motorcycle battery and the
rest of the code describes size, terminal location and vent tube location.
Richard #230, Pacifica
Terminal Semantics - Which is RIGHT and which is LEFT?
- The terminals are viewed as left or right when looking at the battery
BEFORE IT IS INSTALLED. When you look at the "front" of the battery, the
label faces you and the terminals are toward the edge with the label, the
"front." Looking at the battery in this configuration, one terminal is to
YOUR LEFT and one to YOUR RIGHT. This is the common way to speak of
battery terminal configuration. Not installed, where the front may face
the left, right, front, or rear of the vehicle, or even be up or down in
case of a sealed battery. Positive is on the right for both the Classic
AND the GS. Flash #412
Are the reversed terminals on some Batteries hard to rectify?
- The reversed terminals aren't too bad - the negative/ground cable
is plenty long enough to make the stretch, but I'd look at making an
extension or something for the positive cable. Or just replace the heavy
positive cable to the starter solenoid with something 4-6" longer so as
not to stress the battery lug. I don't like stressing the lugs with the
heavy cables, and the positive is a minor problem.
Is the battery ground on the positive or negative side?
The negative terminal of the battery in an F650 is connected to the
chassis and therefore called "ground." Flash 412 (CO)
Is putting a SEALED Battery in Sideways (Stand it on End) OK?
- As per some of the battery models, I do NOT advise placing the
battery sideways - they do have (sealed) vents, and they WILL leak if
overcharged. I've used too many of the larger MF car batteries in boats
and generators to believe that they are completely leak-proof. Superior,
but not perfect. NEVER put in a NON-SEALED Battery Sideways.
OK thats a great list but I cant find any of those in my home town.
What CRITERIA should I be looking for in a battery for the F?
There seems to be some confusion about batteries that fit the F. I have
a list of batteries someone posted, but I don't know for sure if they are
suitable. Well, you can't beat a good Yuasa! Criteria should be:
- Voltage: 12 volts. Obvious, but they do make 6v batteries.
For a bike that seems to have a higher VR output of 15v, a gel-cell that
tolerates higher charging voltages might be nice if you could find one
that fits. (Think of things in terms of water pipes - volts is like
pressure in psi, amperage is like the size of the pipe. You can have
little pipes with high pressure, or big pipes with lower pressure. You can
make the same level of power (watts) with either combo of pipes, if you
vary the parameters).
- Amperage/capacity: OEM is 12 amp/hours. With no kick-start,
at least 10 a/hrs would be needed. You could substitute smaller in an
emergency in sub-Saharan Africa, but not recommended. Larger capacity (if
you can find one that will fit in the compartment) is just fine - like
having a bigger gas tank. Smaller capacity means fewer starts in reserve,
more strain/wear on the battery with each start, and shorter overall life.
A 2 a/hr battery probably won't even click the starter once.
- Physical dimensions/size: Obviously if it won't fit in the
compartment, then... and if it's too small it will rattle (which is BAD
for a wet cell battery) and should be shimmed or braced to prevent
movement, especially on the wires and terminals, or wear/cracking on the
plastic case - that IS acid you know!. Smaller size usually means lower
capacity also. This parameter and the next ones are the tough ones for
- Terminal Orientation: Left side negative, right side
positive. Sometimes hard to find. You could move the harness wires, but
they are heavy and stiff and usually not long enough - changing them
usually requires more modification. But it can be done. For world
travellers, it's a good modification to do before starting out.
- Vent/overflow drain orientation: Not critical, can be
modified by moving the drain hose, but if you see what happens to your
bike when the battery burps hot acid, quite important.
What is AGM and how is that different from Maintenance Free?
Flash Dear Sir: Thank you for your email.
Wet Cell (flooded), Gel Cell, and Absorbed Glass Mat (AGM) are various
versions of the lead acid battery. The wet cell comes in 2 styles;
serviceable, and maintenance free. Both are filled with electrolyte and I
prefer one that I can add water to and check the specific gravity of the
electrolyte with a hydrometer. The Gel-Cell and the AGM batteries are
specialty batteries that typically cost twice as much as a premium wet
cell. However they store very well and do not tend to sulfate as easily as
wet cell. There is no chance of a hydrogen gas explosion or corrosion
using these batteries. Most Gel-Cell and some AGM batteries require a
special charging rate, especially the deep cycle models. I personally feel
that careful consideration should be given to the AGM battery technology
for applications such as Marine, RV, Classic and Performance cars just to
name a few. If you don't use or operate your equipment daily; which can
lead premature battery failure; or depend on top-notch battery performance
then spend the extra money. Gel-Cell batteries still are being sold but
the AGM batteries are replacing them in many cases.
There is a little confusion about AGM batteries because different
manufactures call them different names. A couple popular ones are
regulated valve, and dry cell batteries. In most cases AGM batteries will
give double the life span and many more deep cycles than wet cell battery.
I hope I have answered your question. We have in stock the YB12AL-A.
Sincerely, Jose. Batteryweb
Is BMW installing sealed batteries in all bikes after 2003?
I think I read somewhere that BMW is now installing sealed batteries in
their 2003 bikes. If this is also true for the new F650's, will the GS
battery fit the Funduro? BMW batteries are expensive, but I'll bet they
are less than Hawker. It might be worth checking into. Richard
- No, this is not true for the new F650s. The 2003 and
2004/05 models come with the same unsealed Yuasa battery.
Various Battery Web Misc Comments
- Here is some info from Batteryweb.com on Sealed Batteries: NOTE!
When Flash TELEPHONED to order and told them he was with a BMW he got free
shipping and a possible discount. This may no longer be the case: Hello
there, I just checked out the FAQs for batteries and in the sealed
batteries section it says you get free shipping from Battery web. I just
placed an order with them for my 99 F650 for a sealed STX14L-A2 Sealed MF
12 12 5.3 3.5 6.6 8 $59.00 at http://www.batteryweb.com and could
not get a discount or free shipping. They told me that that promotion is
for two specific batteries only and neither is for F650 models. They both
are for R11XX R series BMWs. I thought I would let you guys know.
- Flash: Q:Here is my problem... in the BMW F650, the
battery is close to the muffler with catalytic converter. The voltage
regulator is cheap and runs VERY high. 14.75V is considered normal. The
sense for the v-reg goes up through the key-switch and so sometimes it
runs even higher. All this adds up to needing to add water to the stock
battery every 500 miles. That just plain sucks. So... considering I have a
12AL-A stock, with about a quarter inch to spare if I remove the rubber
piece, which maintenance free or AGM do you recommend as a substitute?
Batteryweb: A: I think that we (have the) battery you've (been)
fantasizing about! Please see link below for the STX14L-A2,
Sincerely, Jose. Batteryweb
- Opinion on Battery Web: Have ordered twice from them.
Delivery/accuracy was fine both times, normal shipping was included in
their price (rush is big $$$ due to the weight). Too early to tell how
long they'll last. Just be sure to click on the BMW discount link,
otherwise the $$$ is quite a bit higher.
What about Walmart Batteries?
If so how did it work out for you and is it lasting. They sell
one for 27.95 and that sounds like a good price, but I just wanted to know
if anyone else had gone that route. Later, Dirty
- You can buy to try and return it later. artyom66
- I've bought a car battery there. It's OK so far.They didn't have a
cycle battery to fit my 99F650 last year when I needed it. I got one at
Interstate battery, about $44 if I remember correctly.Do they have
batterys for the F bikes now? DaveJ#888
- IIRC, Richard's had good luck with WalMart or other such
batteries. Don't know if it's urban legend or not, but I've heard there
are only a couple of factories that make batteries, and ALL the companies
buy them from the same place and have their labels put on them. I'm sure
WestCo, Optima, and a few others make their own, but with regular wet acid
batts, I'm certain there's not much difference between a DieHard, an
Intersate, or a WalMart. dlearl #476
- Yep, that's where I get the battery for my Classic. I picked out
their most plentiful model that would fit and modified my bike to accept
it. Makes it easy and replacements are always available. Shank
- I have a Walmart battery sitting on my floor at home: maybe I
bought the wrong one, but this one has the posts reversed from the OEM, as
is the vent tube. Besides the vent tube, I seem unable to get the wires to
fit in this backwads position, so I'm taking it back. Meanwile, I bought
an exact copy of the OEM from a local battery shop for $37. Scott,
How reliable are AGM batteries?
- AGM batteries are generally fairly reliable. However
all batteries do require maintenance of some sort, and all batteries
should be regularly inspected. AGM batteries are probably a better choice
for the F650 since it can be a pain to check the levels of your battery
every week. They have also been tested and used in many applications for
many years now. So yes, AGM batteries are reliable - but remember it still
needs maintenance. And a quality battery tender is a good idea.
Has anyone heard of or used BigCrank batteries?
- These appear to be a re-labeled Deka PowerSports
battery. The ETX15L has been fitted to an 04 model GS using the tray mods
mentioned in the modifications
Modifications and Installation
This section is focused on proceedures to modify your bike for
different batteries. Check the battery lists to see what batteries you
could you, and click on the link to see the modifications required. There
are also a few other modifications related to drain tubes.
Battery Removal - Disconnecting and Reconnecting
Supertech, Brian#179, Andy #982,
- Always, Yes Always disconnect the negative terminal first and
ALWAYS, when reconnecting, connect the positive first. ANY Battery, Bike
- You connect the positive terminal first so that if you slip when
connecting the negative terminal, and touch your wrench (or screwdriver,
or STEEL WATCH, so remove it. (ed) whatever you're using) between the
terminal and the frame, you don't arc-weld your wrench to the battery, to
the frame, etc.
- If you connected the negative terminal first, then slipped and
touched the positive terminal and the frame with your wrench, you'd
complete a circuit (a short circuit - no resistance) and sparks would fly.
- For the GS, the manual says: Disconnecting the battery clears all
entries (such as errors, adaptations) from the BMS control unit memory.
The loss of the adaptations may sometimes lead to engine performance being
temporarily impaired when the engine is restarted. The BMS restores the
lost adaptations itself over the following operating hours. Switch on the
ignition. Open the throttle once or twice fully with the engine off.
Motronic registers the throttle valve position. Installation is the
reverse of the removal procedure: Pay particular attention to the
following: Caution: Connect the positive battery terminal first, then the
- Also for the GS. The FI programme only learns about air density etc.
by trial and error. It is not heuristic, it follows a mathematical model.
Opening the throttle three times before firing up the engine just tells
the ECU the max and min throttle positions taking care of stretch in the
throttle cable and other bits that change over time. It also tells the ECU
to start from a factory set of parameters that are almost certain to get
the system running. Normally it stores the last settings and assumes the
air density, fuel rating, throttle positions etc, is the same as last
time. It uses this as its first guess and fine tunes from there. If it
does not have this info, it will resort to the original settings or a back
up mode. Typically the engine will run rich to protect itself in this case
and in a get you home mode may be so rich it will soot the plugs defeating
its own attempts to get the right mixture. The battery is designed to be
removed. If the engine is OK you don't really need the error memory. This
memory is just a list of fault codes. The only thing you need to do is
give three twists on the throttle when you reconnect and maybe clean the
air filter and plugs. Andy #982.
- You also have to disconnect the Drain Tube, which just slides
off the Nipple at the SIDE of the Battery. This is not a problem on
Maintenance-Free Sealed Batteries, as they do not have a drain tube.
Here is the GS Battery, exposed.
Q. Can I access the GS Battery without removing the RHS AND Centre
Sure. See the GS Fairing
Fitting a Westco in a Classic
- Westco Sealed
Batteries: 12V14L-B is the correct Westco battery number.
- Westco's sealed battery for a CB750 Honda or a 900 Kawa will
fit right in the F650 box if you don't use the tray the stock battery sits
in and are willing to bend your cables around a bit. Its also 190 amps as
opposed to about 160 for the stock I believe. Mike.
- The (SEALED) Westco Battery is their 12V14L-B. Installation
takes only a few minutes and no modifications are necessary other than
getting rid of the plastic tray the stock battery sits in. See
.That's only a few bucks more than the stock wet Yuasa. I've seen this
Westco battery recommended for the KLR-650, so it should be plenty tough
enough for the F. Dimensions are 5 5/16 x 3 1/2 x 6 9/16, which is about
a 1/4 inch beyond the stock battery width and height-wise. I've measured
it out and it looks like there's plenty of room to fit it. Per the FAQ, it
appears that others have successfully made this switch. Specs are 12 volt,
14 amp/hr, 190 CCA. Price was $65.95 minus 10% because I ordered a charger
too (finally). T-boy #456.
- I also finally put the Westco in my bike. Like T-Boy said,
loose the sleeve. You may want to run a wrap or two of duck around it
though. If you call a dealer and their looking it up based on the F650
because you don't remember the model number, they won't find one. Tell
them to look for the one that KLR 650 uses. I've had a 14 amp battery in
the bike since Redmond. I've noticed the lights on bike seem stronger and
my riding partners tell me that my tail light doesn't flicker like it use
to. I also think that extra 2 amp will come in handy on cold days and do a
better job of running the heated grips and what ever is plugged into the
accessory socket. Johnathan #145.
- Based on the specs, the Westco weighs over 5 lbs. more. At
present no-one knows if over the long-term the bracket in the F can hold
the heavier battery. Here are the full specs on both. Mason
- I ordered what I was told was a Westco/Panasonic battery from
www.batteryweb.com. Received a
Universal X14L-BS (ref. 12V14L-B); Measurements & Terminal Configuration
seemed OK, so I installed it. Fit fine until I put the left side bodywork
back on...the bottom screw was tight, and when I got it tightened
properly, could see that the top front corner of the battery was pushing
the side-cover out just a bit (the plastic post with the rubber tip that
used to press against the frame rail under the seat is now ~1/16 away. Not
a big distance, but something is definitely interfering between the two,
it's getting bent/warped/stressed, and I'm sure vibration & miles will
make SOMETHING worse. Had to trim the top part of the battery hold down
piece, as the new battery is about 1/2" taller, bending it over the top
also bowed it out. I trimmed it so it doesn't go completely over the top.
The big problem was with the battery terminals. I had to run the negative
post bolt through the top mount instead of side mount, and make sure NO
wires routed between the battery and side cover. Had to remove the plastic
cover from the + connector, reroute that wire (after adjusting the other
end that connects to what I am assuming is a relay), and straighten the
connector that bolts to the + battery terminal. After all that, the
sidecover went on just like in the old days...the bottom bolt part of the
sidecover rests against the frame/clip, so I no longer need to crank down
on the bolt (flexing the sidecover) to bring it up against the frame/clip.
No duct tape on my battery...not sure if the vibration will kill the
battery first, or if the glue on the duct tape might plasticize the
battery case first. Still pondering a plan C alternative. Marty
- 12V14L-B is the right Westco battery number. I'm assuming you
dumped the plastic tray the stock Yuasa sat in. If not, do so. The plastic
post w/ the rubber tip should stay put if you push it back in. If not, it
should once the seat is back on. If you haven't done so, you may want to
cut the top hook part to the cover that holds the battery in place. This
isn't necessary, but I cut mine at the bend at the top and that seemed to
give me an extra bit of wiggle room for the plastic side panel. As far as
the bottom screw being tight, that's better than loose isn't it? I haven't
found any disadvantages to the Westco Battery yet. No modifications were
necessary to fit it other than simply not using the battery tray. If you
go w/ the Westco you may want to cut off the top hook part of the outside
plate that keeps the battery in place (trim it at the curve), but, like I
said, it's not necessary. T-boy #456. (Wash., DC)
- How did you attach the cable to the post? These posts work both
horizontally and vertically. Mine hit until I switched the cable to the
top of the post with the bolt running down. That bought me a bit more
clearance on the side cover. One reason mine is so tight is that after
removing the stock plastic sock, I wanted some vibration protection so I
fitted a piece of thin closed cell foam under and behind the battery.
- If you decide to go for a Westco (Panasonic, they're the same
thing re-branded), give www.batteryweb.com
a try, but call their 800 number. I succeeded in getting a discount and
free shipping by telling them I was in a BMW club. Alan #442
GS/Dakar Tray Modifications
Fitting alternative batteries in the GS/Dakar is a little harder. There
is not much spare space where the battery is, so you can try one of these
modifications. There are two basic methods: The most common is to re-drill
the holes in the metal tray. An alternative is to bend the metal tray.
Method 1 (by BradG#1002)
Here is some information on converting from an OEM Yuasa battery to a
Westco 12V14L-B in a 2001 GS.
- After trying to find a good deal on a Hawker SBS8 I gave up and
went with a Westco AGM type battery. It was available at my local
motorcycle accessory retailer, Road Rider, San Jose, CA. Here are some
points to keep in mind if you decide to go this route.
- At Road Rider the Westco was called a 12V14L-A2 not a 12V14L-B. I
was told the -B referred to vent location which is meaningless in the case
of a sealed battery. I did confirm the outside dimensions are the same.
The price is right. RR charged me $57 + tax.
- The OEM Yuasa in my bike measures 3.12 from front to back. The
new Westco measured 3.5. The FAQ mentions someone installing a Westco
successfully in a GS (2001+). It mentions a tight fit. I was unable to
squeeze the new one in. The new battery is also taller but there is enough
room to accommodate it at the top (well sort of, see below).
- I went to work trying find a way to get an extra .375" of space.
The battery well is wider at the bottom (front to back). The air box
angles forward as it goes up. I removed the rubber pad on the front face
of the air box and loosened things up but still there was no way.
- I ended up making a new bracket to replace the one that holds the
battery up. There was some space available at the front between the
support bracket and the plastic air dam (firewall like thing). The new
bracket uses that space and thus adds about a .25" more room for the
battery on the front side.
- It all went back together and JUST fits. I have no idea how this
could be done without a new bracket. I suppose bikes can vary in
tolerances or the air boxes vary from bike to bike. So beware, the Westco
may NOT quite fit your bike.
- As for weight the Westco is about 11.5 pounds vs. the Yuasa's 9
pounds. I shed just under a half pound with my new aluminum bracket (the
OEM is steel). Net gain about 2 pounds.
- The battery leads worked with no problem. Here are a couple of
pics of the bracket and new battery installed.
|New bracket is the gray piece
||New Westco installed
- Unlike the Classic, the GS does NOT have a plastic tray to ditch.
Not sure how Joe #1065 got his to fit. Until I made a new bracket to hold
the battery it would not sit flat on the bottom. (Perhaps install a shim
to fit the base?. ed) The battery would have been tilted slightly and thus
resting only on one bottom edge. I also had to loosen/move the air box to
get it in.
- In my opinion, if you want a clean, easy, installation, go with
the the Hawker SBS8 and the TT bracket.
- YMMV but I wanted others to know that this battery may not fit
in a 2001 or later GS model. The space BMW provides is tight. bg, 2001
Method 2 (by Scott, ID #1244)
|Here is some information on converting from an OEM
Yuasa-compatible battery to a Westco or other AGM (12V14L-B compatible)
battery in a 2002 GS Dakar. While some users claim the "maintenace-free"
battery will fit in a GS battery slot, I found mine would not: the OEM
battery fits snug as it is, and the AGM is wider by 5/16-inch (Length and
height are of no concern. For the record, my AGM battery is a CNB model
CBTX14AHL. It measures 5 5/16L x 6 9/16H x 3 1/2W. The OEM measured 5
3/16L x 6 5/16H x 3 1/16W.)
|Looking at the situation, it seemed to me that a guy/gal could
remove the metal bracket that the battery sits on, and by drilling new
holes, essentially slide the vertical part of the bracket forward. This
would make the width of the battery chamber wider. See below image; green
arrows point to red dots that are the new holes (one hole is hidden from
- Remove seat. Remove the center tank panel, and the right side
panel. Remove the battery (negative terminal first).
- Remove the two lower airbox screws (the ones that are located
below the front part of the seat). Remove airbox and let it hang to the
right side. I also removed a hose from the bottom of the airbox, to make
it easier to get to the bottom side of it. This may or may not be
necessary. Place a rag in the throttle housing opening to keep stuff from
falling into it. (You WILL drop something in there if you skip this
- Using a torx driver, remove the screw from the plastic relay
cover. Remove relay cover.
- Using a socket, remove the two nuts that hold the metal bracket
near the plastic relay cover.
- Using an allen wrench, remove the screws (part number 8 in the
diagram) that hold the plastic battery tray to the bracket. You'll find
that the nuts (part 11) are spot-welded(?) to the metal bracket. Place the
bracket in a vice, and using a chisel and a hammer, knock off the two
forward nuts (leave the rear alone as you will not use this anymore).
|Measure the difference in battery widths. My new AGM was
about 5/16" wider. Alternatively, if your OEM battery does not completely
fill the battery slot (i.e., there is slack room), set the new AGM battery
in the slot and note how much room is needed to make it fit (as shown in
the photo to the right; photo and idea courtesy of fellow Dakar rider
|Measure the difference in battery widths. My new AGM was
about 5/16" wider. Alternatively, if your OEM battery does not completely
fill the battery slot (i.e., there is slack room), set the new AGM battery
in the slot and note how much room is needed to make it fit (as shown in
the photo to the right; photo and idea courtesy of fellow Dakar rider
Using some loctite and lock washers, re-attach the
plastic tray to the bracket using the new holes. Notice that the rear-most
hole is useless now, so you will be using just the two forward allen
screws and nuts (unless you want to run a screw through the edge of the
plastic tray; I figured 2 screws is enough)
I didn't actually confirm this, but visually it seemed that
the upper part of the metal bracket will now extend INTO the plastic relay
housing on the right side: the whole thing is now shifted forward
almost 1/2 inch, and it was almost touching the housing before this
operation. Given that assumption, I trimmed away the lower part of the
plastic cover, cutting along the line shown below (I carefully used a
bandsaw; a pair of wire cutters, etc. might also work just as well, and
would be safer.)
Alternatively, you could also cut off 1/2" or so from the upper ends of
the metal bracket, through the old bolt holes; I prefered to leave them
intact. (see "feedback" below; dmemt's method didn't require modifying the
relay cover as he didn't shift the bracket as far as I did).
- Now that the bracket is re-attached to the airbox, remove the
rag from the throttle housing, and re-install airbox to the throttle.
Notice the snorkle end of the airbox needs to slip into a small hole near
the headlight. Also, If you removed that hose from the bottom of the
airbox, plug it back in before installing.
As you install the airbox back onto the throttle, the two new holes in
the upper part of the bracket will be slipping into place over the
mounting bolts. Notice that your rubber battery retaining strap needs to
be installed at this time: the metal clip it hangs onto will now be pushed
forward against the bike frame, and cannot be installed later! (on the
upside, it will never again come undone the next time remove the battery!)
Notice the new gap along the forward edge of the tray bottom: this is the
new width you just created for your new battery!
Install the two lower airbox bolts. Install the plastic relay cover.
Install the new battery, postive terminal first. The negative
battery cable on my bike did not fit the battery very well, so using a
round file file I enlarged the copper hole a little. After a minute of
filing it slipped right into place.
Install right side tank panel and center panel. Install seat.
Set the clock and take your battery for a ride!
Start to finish, I spent 1-2 hours working on this. The AGM seems to
run almost 0.5 volts higher than my OEM wet-cell. Also, it has about 30%
more cold cranking amps. (about 215cca vs 165cca.) My bike now starts much
faster than it ever did with the OEM-type wet-cell batteries. And as a
bonus, I don't have to worry about checking water levels every week!
Scott, ID, #1244
Method 3 (by dmemt, #1464)
Just thought I'd do a quick post on how I fit a Yuasa
YTX14AHL-B2 into my battered Dakar. Basically, I just drilled all 5 of the
stock bracket holes 1/4" back from the originals, ground a bit off the
front right bracket tab for clearance, and flattened the front hold-down
tab a bit.
A few tips:
- The nuts on the bottom of the bracket are epoxied on. I
"broke" them loose with an 11mm box wrench and a hammer.
- A drill press would have been helpful, since the new
holes overlap the old holes by a couple 32nds. I wound up with something
more like slots when I was finished butchering the plate, but it still
seems to be solid.
- To flatten the front hold-down tab, I hooked the strap
over the tab, then hammered it vertical. It still comes on and off, but I
wouldn't want to "fish" it on now. I'm not sure if there is room for the
thin airbox foam rubber pad that the back of the stock battery rests
against. I'd removed mine earlier while trying to figure out what would
work, and there may be room to leave it in there.
- Top panel clearance seems to be fine. The battery/oil
tank/airbox assembly is still "floating" above the frame on the right
side. There doesn't seem to be as much battery vibration isolation as
stock, but hopefully the new battery can take it. I'll have to check for
contact wear after I do some off-roading, but I don't anticipate any
Note: In TWO instances the YTX14AHL-BS has been installed with minimal
- On a 2002 GS: the Yuasa
YTX14AHL-BS will fit into a GS without modification, other than removing
the foam-tape at the back of the battery compartment intended to keep the
smaller stock battery from vibrating. It's a very tight fit, and it'll
take a few minutes to figure out the right angle before it pops in there,
but it works, and the terminals are in the reversed BMW-style
- I read all the pages and pages of stuff in FAQ on putting a
maintenance free battery in my 2003 F650GS Dakar. I was prepared for
redrilling, cutting and bending on the battery bracket. It turned out to
be a NON EVENT! ... To be safe, I bought a spare battery holder from BMW
to hack up. P/N 13-71-2-343-567. A whole $7.56 with a discount. While I
had all that stuff ripped out, I did the BMW heated grip kit and the
power outlet. Now that was a bunch of messing around! Then I looked
closely at the new battery bracket...it looked odd. Sure enough, the new
one had different dimensions of the two tabs that bolt the bracket to the
crossmember..it makes the right side of the battery about 5mm farther
forward than the other bracket on the bike. Then I removed the little foam
pad on the front of the air box that touches the battery. Replaced it with
a 1mm thick tire patch for the battery to rub against instead of the
airbox. While I was at it I opened up the snorkle to the airbox.
Everything slipped together just as nice as anything! No bending, no
Method 4 (by billmallin, #1629)
- I read Scott's post about installing his battery in his GS and
ordered myself one. I installed it today while doing my 12,000-mile
service. So, I was fully prepared to do the modification like Scott did,
but when I got to looking at it closely, It was about 1/4" too wide, but
it appeared it would go in there.
- It looked as if the bottom of the tray was wide enough, but the
top was a bit too tight. So I simply took a mallet and bent the metal tray
with a few strategically placed hits (see arrows in diagram).
- Hint 1: I took out the bracket and removed the plastic part
bolted to the bottom (you know, that plastic deal that holds the snorkel
to the air box).
- With a piece of wood under the bracket on the floor and rubber
mallet in my hand, I kept tapping it until the battery fit. Tap it, try
it. Hit it, try it. Smack the crap out if it, try it. And so on until it
- I can confirm the F650 and F650GS take the same (OEM ed)
battery, and yes the Westco Battery (sealed) 12V14L-B does fit into
both bikes. It is a TIGHT fit but works fine with no modifications,
period. The battery is 5-6 lbs heavier, 5-10% bigger in overall size, but
again, it fits! Joe#1065
- Have a Westco, sealed, in one of my Hondas. Excellent! The only
battery I have that gets the Battery Tender hooked up once every 3 months.
My others are on every day. Starting to think the Westco needs no
maintainer even with minimal use. It just works! Art 884
Any problems with the oil reservoir melting the side of the
(Assuming outright melting isn't an issue, is there still any reason to
think the lack of space around the larger batteries might cause heating
problems for the battery?) Dano PDX #1164
- Not sure which is worse... next to the oil tank (FI)
or on top of the muffler crossover pipe (Classic). Marty #436
- The length of the AGM is the same as the OEM
wet-cell, so the AGM has the same kind of contact with the heat shield as
the OEM . . . wouldn't expect any melting(?) Scott #1244
Hawker (SBS8 and PC310) Sealed Battery
- Some people have reported difficulty getting SBS8 batteries. An
alternative appears to be the Hawker Odyssey PC310 (see below).
- You can also try the more expensive Hawker battery,
(David H Park runs the
Hawker battery in both his Rallye and Adventure F650GS based bikes.) This
is a picture of the Hawker battery installed in the F650GS/Dakar/Rallye.
SBS. Notice that there is an additional brace as the battery is not
as tall as the standard battery. No acid drips to worry about with this
battery and you have more cold cranking amperage. The Hawker SBS has a 15
year lifespan at Float and a 2 year minimum shelf life (both at 20C).
It's a much better battery for shock and vibration which is why it's used
for off-road applications. The battery type is the SBS not the Odyssey.
The product has a two year warranty.
Touratech part #, 130-0001, 239 Dm Battery
130-0004 19.90 Dm - F650GS adapter (no F650 adapter at present). David
H Park. #711
- The specs indicate that the Odyssey should provide superior starting power
than the Westco; however, whether the additional 30 CCA's is important
seems unclear to me. By contrast, as the Westco holds more total power,
the Westco should provide a little more of a cushion to run lots of
electric gadgets at the same time without running down; however whether
this 7.7% margin over the Hawker is material is also unclear. Both have
clear advantages over the stock battery. However, I would conclude that as
the Westco is much less expensive, the Westco would appear to be the
better value. Other considerations: Both the Hawker and the Westco are
supposed to be very durable and more vibration resistant than standard
batteries, and both are also supposed to be better at holding a charge
when unused. However I don't have any information to determine which might
be better in these respects. Both should be better than the stock battery.
- Brad, I've recently gone through the same search as you regarding the
Hawker batteries, with the same somewhat confusing results. It's unclear
to me what the differences are between the Hawker SBS 8m sold by
Touratech, and the Hawker Odyssey, available through several sources as
you point out. I'm referring to differences in technology, etc., not
sizes. Is there anyone who can help clarify this point? Thanks. Mike
- The Hawker SBS8 sold by Touratech isn't one of the "official" batteries
marketed by Hawker/Invensys as "automotive" but it's perfect for the
F650GS/Dakar. It's smaller and lighter than the other "compatible"
batteries. Touratech has an adapter plate for this which works great.
There is no real difference in technology. I spent quite some time with
the techs at the Indy Dealer Show from Hawker talking about this
application. They were fine with the SBS8 and intrigued that it was
spec'd. It's just not "shown" here in the US due to a product management
decision (or lack thereof). Otherwise it's fine. I've got this in both my
bikes and love it. davidhpark711
- The SBS8 is not typically sold as a "motorcycle" or "automotive"
battery so Hawker and distributors don't know about it. It's a "telco"
battery used for standby systems. Touratech chose this because it fit the
power/weight requirements of the Rallye bike and in Europe the SBS8 is
more readily available without the specialized marketing of the
"automotive" Hawkers. I've had a hard time getting replacement or extra
SBS8s here through distribution. That being said, it's been a fine battery
and a bit smaller/lighter than the stock (need to use the Touratech
mounting plate). davidhpark711
- If the battery goes open circuit, while the engine is running, its the
same as pulling a battery cable off the battery on your car, while it is
running, sometimes a recipe for an electrical disaster :-( IF you want
avoid the potential for these problems, the best bet is a Hawker/Odyssey
etc AGM (Absorbed Glass Mat) battery, they are NOT SLA batteries!. They
are used in aircraft etc and are very reliable, and fortunately available
in many sizes.....probably to fit our bikes. As I have always said, a
battery is a consumable, you get 12 months out of it, and its bonus time
from then on :-) Jack, F650GS, Queensland, Australia.
- I had the same problems, after dropping it a couple times my battery tray
and engine cover started eating away so I got the Hawker battery. No
trouble to install. The battery is smaller then the stock and requires a
little 'extension' to install but no big deal. I've had it in there for
about 6 months now with no problems. I think I got it off of the Touratech
website, but they seam to be having some problems right now so I can't
give a specific link.
Stumby 01GS (VA)
- When the battery comes, you will find it is the same size as you
original battery, except it is a little shorter. You will also note that
the battery post aren't just like normal motorcycle batteries - they are
smaller and they stick straight up. To fit the battery in the space on
your bike, you will need to make/buy a spacer(s). Touratech makes a spacer
intended for this application. I decided to make spacers for the top and
the bottom, effectively lowering the top top the battery, so that the
battery cables would be an easy fit over the battery posts. I made my
bottom spacer out of cardboard and covered it with fiberglass tape (don't
use the styrofoam that the battery is packed in, strofoam might not
tolerate the heat of the engine and the oil tank - it melts). The bottom
spacer is ~1 1/4" thick. I did use the styrofoam that came with the
battery (packing) to make a block to go over the top of the battery,
between the battery and the factory rubber retaining strap. This piece is
actually two different shaped blocks, glued together and covered with
clingwrap and fiberglass tape. I have 0 miles on this mod so I can't
guarantee that the spacers will work as good as what you can buy from
Touratech. I am planning on a 200 miles test this weekend :o).
Odessey PC 310
- It appears the SBS8 is no longer available, and the most common recommended alternative is the PC310. More reports on its long term usage are welcome. Winter #1935
- I've had a PC310 for over a year now and it has been faultless. I believe it is a replacement for the SBS8 I read somewhere. The only hiccup I have had was when I drained the battery totally (long story - my fault) I couldn't jump start it so I had to take it home and put it on the Optimate overnight. Since then I've not had a problem with it. I give it a trickle charge once a week or once a fortnight if I feel it needs it (I have a Signal Dynamics battery minder thing fitted to tell me how the system is charging) and the freedom from worrying about cell levels is worth the extra money. I've had no trouble in cold weather (my bike lives outside) and I reckon if it did get cold enough for the battery to fail, it's probably fate telling me it's too cold and dangerous to ride anyway. brassmonkey001
- After looking back at the photo of the Hawker SB8 on the Tech. FAQ site, I believe the Odessey PC 310 is the same battery but made to be sold in the US. They are both made by the EnerSys Corp. and this one is identical but much easier to find. Rocketman
Has anyone had luck installing the SBS 8 in a 2002 GS (looking through
the forums it looks like artyom66 did in 2003)? If so
how were you able to do it? apostate #1618
- Cr*p, I can't copy my image off my ETK disc nor from the
Max online fiche. Here's the link for the battery
tray which has a locating tab for the wet cell battery which must be
cut off to allow the longer SBS8 to fit. [ Here is
an image of the
SBS8 and the battery tray (thanks to GSWayne) ]
- Here's how to do it:
- Pull the right side faux tank panel off
- Then pull the air snorkel off by undoing the two screws that hold
the C shaped mating piece which holds the air snorkel and air box
together at the air filter port.
- Once you've got the air snorkel off, you'll need to unscrew the
battery tray (3 screws I believe and pull it out. This is all easy as pie
- I used a Dremel to grind the plastic off but a bench grinder or a
hacksaw would work fine as well. The material will have a tendency to melt
if you grind too fast or too hard so don't worry about dorking up the
precious and coveted virginal German plastic (imported from Romania or
Bulgaria or some other cheap place junior EU country).
- Once you've ground down the locating tab down to flush with the
bottom of the battery tray, just reverse the removal and you're battery
will slide right in snug as a bug in a rug.
- The TT adapter is worth the wait if you run a lot of accessoreis
because it give you an alternate site to attach those wires. It helps to
clean things up a quite a bit in the R&R process, too, without having to
unhook your main power to the bike. Key, IYAM. NothingClever
For those of you running the Hawker with the Touratech adapter: Does
the adapter just fill the extra space, or is it also needed to make the
electrical connections work? In other words, would running a Hawker with a
home-made adapter be a decent option? Dano PDX #1163
- You could probably make something to provide the
same functionality. I think a couple of people that were waiting for the
adapters did. The Touratech adapter does make it a little easier to
connect to since it provides longer terminals and relocates them a bit
which makes getting things hooked to them a little easier I would imagine
(having not tried to hook it up before the adapter arrived). apostate
Exide / Yuasa Sealed Battery
- I have a Yuasa YTX12-BS that I replaced my 4 1/2 year old original
in my ST 6/01 prior to making 7K coast-coast trip. The only way to get it
to fit was to remove the rubber battery box liner, and stand it on end
(the TERMINALS ARE REVERSED, but the cables still reach). I have had it in
for 15 months and have never looked at it, have let the bike sit for as
long as 3 months, and it holds a charge, seemingly, almost forever. The
only one I personally have used that is any better is the Odyssey in my
Ural - after sitting for 7 months, cranked strongly and immediately. Look
for an AGM (absorbed glass mat) battery. Zero maintenance. Hal #15,
- I found a Yuasa YTX12-BS GRT Maintenance Free Battery at
http://www.discountmotorcyclebattery.com/grt.html (go figger).
800/654-0565 $47 + $8 s&h = $55. Dimensions are 6.000" x 3.4375" x 5.125",
1.2A 180CCA And the TERMINALS ARE REVERSED, which I don't see as all that
much of a problem since once you get it IN the bike, you never f*** with
it again. Stock is 6.3175" x 3.1875" x 5.3125", so the rubber deal
probably needs to go. I haven't measured the battery BOX yet to see if
this will fit. Probably do that tomorrow night. Flash #412. NOTE! When
Flash TELEPHONED to order and told them he was with a BMW he got free
shipping and a possible discount. This may no longer be the case: Hello
there, I just checked out the FAQs for batteries and in the sealed
batteries section it says you get free shipping from Battery web. I just
placed an order with them for my 99 F650 for a sealed STX14L-A2 Sealed MF
12 12 5.3 3.5 6.6 8 $59.00 at http://www.batteryweb.com and could not get
a discount or free shipping. They told me that that promotion is for two
specific batteries only and neither is for F650 models. They both are for
R11XX R series BMWs. I thought I would let you guys know. John
- Exide Yuasa NP12-14R, 14 amp/hr, 164 CCA. Dimensions 5
5/16 x 3 3/16 x 6 5/16. The dimensions seem to indicate it will fit with
the plastic sleeve, contrary to the FAQ info on the Westco battery which
is apparently larger. Cathy983 Halifax.
- If they list a Yuasa YTX12L-BS, it has the terminals
that would fit best. Todd#389
GS Charging Access
- Note: On 2004 and later model GSs, you do not need to create
charging access. Under the seat (near the fuse box) is a positive
terminal, and on the oil filter cover is a negative terminal.
- There is a wonderful charging unit that is neat and tidy and
can be left on permanently I have one for my F650 It is an "OPTIMATE" the
leads are left permanently connected to the bike usually by cable ties to
the frame. The optimate charges initially at 14V until the battery is up
to about 12v then it switches to trickle charge. Once fully charged it
switches itself off. Thereafter it turns itself on regularly to check the
charge, if needed it will top up , if not it turns off again. My other
bike is a Honda VFR750 which stays in the garage over the bad winter
weather, and when the F650 isn't being charged the VFr is connected
permanently and I have done that for 4 years now. There is another similar
device called an "ACCUMATE" does the same thing. M7P and MPS in the UK
sell them. Alan
- Thanks to everyone for their hints and tips. Last night I
bought some 10-gauge wire, 10-gauge spade connectors (insulated), and some
small battery clips. Some heat-shrink tubing and plastic cable housing
(the spiral stuff you wrap around wires to protect and tidy up with)
finished it off. I ran the positive wire down to the seat area and patched
in a fuse, then routed the wire back up to the battery and out the front
of the tank (blue wire is for the accessory light fuse). I learned with
the lighting fuse that it makes lots of sense to put the fuse where you
can get to it easily (update: I removed the 20A fuse as it always blows
when jump starting. This may or may not be a good idea in the long run,
but for now I'm jumping without a fuse, and so far, no troubles.) This
isn't rocket science, but I'm including photos of the operation just in
case it is helpful to anyone.
The resulting pigtail hides down low in front of the tank (both
"+" and "-" wires). I had a spare connector, so I plugged it into the "+"
connector to guarantee the unmated metal spade didn't touch any metal on
the bike (despite being insulated, the spade "could" touch metal when left
unmated). When needed I can just pull them up as shown.
I then made a set of mini jumper cables with the left-over
parts (or "Barbie" cables as my wife says). I think I'm now ready for
winter. Scott, ID #1244
- You can find clips that will handle a goodly amount of current.
Watch your wire size, AND the type of insulation. The insulation on
Mega-Speaker wire (large gauge) melts pretty easy. Unfortunately, most
decent gauge wire is really stiff and hard to pack. There are some
commercially made booster cables for motorcycles (I've seen them for sale
at rallies). The problem with using the accessory outlet is the fuse. It
will blow if you exceed its limit, and the battery will charge no more
until you realize the fuse is toast and replace it (a 15 amp car battery
charger will do this, likely jumping it through the outlet will as
- I bought a battery tender when I picked up my
bike...temperatures here are already into the teens at night and my garage
is not insulated...colder than a witches t** in a brass brazier. The
dealer told me very confidently I wouldn't have to worry about the water
level in the batter-go figure. I found the battery tender (Yuasa) quite a
bit cheaper at a local shop than at the dealer, but it doesn't have all
the cool little connectors that come with the BMW version (it has some
pigtail connectors, accessory outlet connector and one that looks like the
thing you use for a Gerbing heated vest connector). Runaway #1259
- I usually commute with my bike 3-4 times a week. It is a 20
minute drive. 10 min highway and 10 min city. I Installed heated grips
last Friday, so I don't know how that will end up. But before that I have
had no problems with the battery for the last 2 years since I bought it
(used). I store the bike outside and today it was 7-8 degrees above zero
(Celsius). I'll keep an eye on the battery when I start using the heated
grips. Spakur #1117.
- If you have a BMW accessory outlet and want to charge the
battery while it remains hooked up to the bike, I would say no. (I do it
all of the time with my bikes.) However, I have never had to charge a
fully discharged battery while the bike. When you hook up the charger that
thing is really going to bubble for a long time (maybe over a day) while
it is charging. It is also going to generate a fair amount of hydrogen gas
while it is charging. I would be concerned about acid leaking out of the
overflow tube or gas accumulating under the tank (do you have a GS? Is
that where they hide the battery now?). There will probably not be a
problem, but removing the battery would insure that nothing happens and
will allow you to top off the battery water when the charging is
completed. Richard #230: 1997 Funduro
- I usually just plug the tender into the accessories outlet, but
like Richard said, that's for maintenance rather than charging a
completely empty battery. Runaway #1259 (CO). '03 black
- I have done the same left the parking lamp on and it drained my
battery. Do you have a classic or later year model? For my classic I used
the little fused adapter that came with the tender. Permanently installed
this allows you to just plug in the charger when ever you think its
necessary by just undoing the seat to access the little cord. Will in
- Having seen lead-acid batteries explode while being charged at
other than trickle currents, I would recommend removing the battery to a
safer location if you are going to use an external charger with high
charging current (e.g., 1 -2 amps initial). Teddco
GS Battery Drain Tube
There is a little tube that runs from and overflow outlet on the right
side near the top of the battery (F650GS, but classic also has this
tube)). Is there supposed to be a small hose clamp on this? (Mine has
no hose clamp). The tube either slipped off the battery by itself or the BMW
tech who did my 6k service forgot to put it back on (while he was busy
mis-routing my throttle cable and stripping threads). The result being a
fair amount of battery acid leak on to the negative wiring harness and a
few other places. I did some good off-road riding, and that's when the
leak happened. Normally the overflow tube would carry the acid down under
the frame and safely away. So, do you see a little hose clamp on
- Mine has fallen off several times of its own accord. Using a ziptie
will keep it firmly in place. In my case, can't blame this one on anything
but the nature of the beast and a less-than-optimal design.. Gerry
- I've used a tiny nylon tie wrap to secure the tube, or in extreme
cases, used super glue - which makes it NOT removable, must be cut off.
- On my 7/2000 GS I use a small ziplock, but another problem was the way
the drain hose used to be routed down the side of the battery, between it
and the air cleaner housing. It was badly pinched, and didn't appear to be
able to let any fumes or pressure out. I finally cut it out of the way &
ran a new one toward the front of the battery, across the top of the
terminals to the LHS of the bike, and then down and to the rear. Once the
clear tube got down toward the rear of the cylinder head, I joined a piece
of the small bore black poly pipe that you use for micro garden
irrigation, and ran it back & down near the Centrestand. The poly tube is
good because it is harder for it to get pinched. Fitzy from OZ
- On a US Classic you can use one of the "extra" clamps from the
cannister assembly. From my cannister I have used the extra clamps for the
battery vent tube and for an inline fuel filter. Chris in Santa Cruz,
picture shows the battery tray, and the drain tube in its "normal"
position. Winter #1935
Hooking Tender to Alternator or Battery?
- "new to me bike" (97ST) came with battery tender
hooked up already (gel battery - yay!). when i follow the wiring, they've
hooked the pigtails up to the alternator, not the battery terminals. is
that correct? better?
reason i was looking ... i want to put on harness for gerbing jacket
liner. i have adapter from warm n safe for sae to coax. thought it'd be
neater to only have one cable coming out - and just switch out adapter
when i want to charge battery.
so here's my question - does it make a difference where pigtails are
attached (alternator vs battery terminals)? am i less likely to drain the
battery itself with the 'lectrics if i hook up to alternator? nb - bike
has heated grips and piaa lights - yes - i know - don't run 'em all at
once and get a voltmeter.
what are folks opinions on the "best practices" here? ishtardnce
- If I understand what you're saying, the Battery Tender pigtail is
connected to two of the three yellow wires.
If so, that is frickin' STUPID. The ONLY benefit of that is that it is
impossible to reverse the polarity. But the connector is KEY, which makes
doing that REALLY difficuly anyway. The battery will never charge
sufficiently through the diode drops in the voltage regularor, ESPECIALLY
if it really is a GEL battery (as opposed to an AGM that the uninformed
often call "gel cells" because they are ignorant of the
Do not ever RUN any accessory off the "Battery Tender" connector until you
move it to the battery. SHEESH! Some people don't know which end of a
soldering iron gets hot and operate with one on the wiring anyway. Good
luck sorting it all out. There is a Classic wiring diagram in the
FAQ. Flash #412
- hey flash - my bad. i gave you wrong info. on closer inspection,
the battery tender pigtail had the positive end hooked up to the solenoid
(?!) and negative going to ground on the frame. weird? i thought so...
removed, and replaced with warm n safe's battery harness. will use adapter
for battery charging. ishtardnce #1549
- That actually makes sense. The big wire from the positive battery
terminal goes to the solenoid. So as long as it was hooked to the battery
side of the solenoid, it WAS hooked straight to battery hot. The battery
ground is the same point, electrically, as the frame. Nothing wrong with
Yes there is possible corrosion at all connections. But connecting
to the solenoid and frame ground make less of a mechanical problem at the
battery terminal bolts, especially if there are other accessories hooked
up there. Flash #412
Alterative CS Batteries
- Please see the note at the top of this FAQ about the Drop-In AGM battery. This is the only known AGM battery available for the CS models.
Finally, this section contains all the other questions about batteries.
So if your question is not about batteries only, and is not about
modifying your bike for a new battery, your question should be answered
This bike will EAT your battery unless you check the level of the
electrolyte frequently. Check it at LEAST monthly. Some try to remember to
check it after every few tanks full of gas. EDTA can make a battery last
forever IF you keep the electrolyte level up.
My Battery seems to be low on water. What shall I fill it with?
- Distilled water. And If your battery was low on
water, you had better check the voltage regulator output and also check
the specific gravity of the battery cells. You may have a bad cell and
need to replace the battery, before it takes out your Voltage
What about that Acid in a Bottle? If a battery is
low on water, why can't battery acid be added instead of water?
- Well you could use that too. BUT... The battery
companies say not to do it, maybe they are just trying to sell more
batteries. You add distilled water to the battery because once it is
filled initially with acid the particles that make up the acid are always
in the battery. The only thing that boils off is water so that is all you
add back. Put in EDTA if you want more juice.
How do I put water in those Tiny Holes?
- Recycle a translucent plastic fuel filter. Cut off
one at the widest part and voila ! A funnel just the right size.
Can I add water with the battery still connected?
- No, you do not need to disconnect the battery to top the cells up
with distilled water. However it is fairly hard to see how much water is
in the battery without disconnecting it and removing it from the bike.
While doing my routine 1000 mile battery top off, I was surprised to
find several cells almost dry. This is unusual. Whats happening?
- Do an electrical check, in case your voltage
regulator is over charging. Refer the Voltage
Rectifier FAQ for typical values. Some bikes' lighting circuit turns
on a second coil in the alternator. In your salt air environment, try
cleaning every connection and ground. If that don't get it... you're
likely due for a rectalfrier / regulator.
What about more details of Battery Maintenance?
What about the Battery Overflow Tube?
- Always put it it on. Otherwise In between the frame and the
swing arm is a plastic washer and between the bushing and the swing arm is
a foam rubber seal. A leaky battery vent tube dripped acid onto the washer
and seal and basically ate through them. I never felt any problems but found
this when I took it apart. Mark #403
- Have you ever watched a battery as
it sits on a charger? As the charge is applied to the plates, the
acid/water mix bubbles up. This type of charging goes on every time you
ride from the alternator. There is a build-up of gas inside the battery
and if no vent, the battery can swell. Also, some water/acid mix will
occasionally come out the vent from this gas release. The tip over is also
a culprit, but really not the primary reason for the vent hose. A blocked
off vent is worse than a removed tube though. The main thing is to have
the vent tube so that it is not blocked/pinched closed. Gel Cells don't
need this because of the Gel as opposed to water/acid mix. The Gel does
not give off the gas/bubbling effect like the water/acid mix. Thus no
pressure problems with a Gel Cell. Gar #673
- Had a terrible situation happen last night to my pride and joy., I'm
sick! Went for a ride down a dirt road on my 02 F650 GS Dakar with 2300
miles on it. Got home in the garage and saw a small pool of what looked
like water under the machine. Upon closer inspection I saw the wet spots
all over the fine finish on the right and left side of the engine cases.
You know the gray powder coat on each side of the engine heads and
cylinders. I go to wipe the wet stuff off thinking its radiator water.
Instead I discover its battery acid. It quickly takes a lot of l the
finish off by beautiful metal surfaces. I open the tank area where the
battery is to see the overflow tube has fallen off the fitting. Must of
been the bumpy dirt road. My work dress pants are shot and a pair of shoes
get trashed from particles of acid. Its not massive damage but lines of
corrosion running down what once was pristine finishes. My tube barely
reached the fitting. I had to pull it with some pliers to give it some
slack so it would easily fit. I think that was the problem along with a
too full of battery I'm sure. Bad combination. Biggums
- This sounds like clearly a warranty issue here. No BMW doesn't put a
clamp on this hose. None is needed. When properly installed there is no
problem. Even if the hose is not connected , which I have seen a few
times, no major mess is made. Sounds like the battery was over filled and
the vent tube was left off. I would return to the purchase dealer with a
smile on my face and suggest perhaps a mistake was made here and that
perhaps they should make it right and they should. Remember the smile,
maybe some Krispy Kreams and they should make it as good as new. Clearly a
mistake has been made here. If that doesn't work find a new dealer. If the
vent tube on your bike is not long enough most likely it is not routed
properly. There are several ways these things come routed from the
factory. You might try a different route. Be careful one route causes the
tube to be pinched by the air snorkle. But even then no leakage occurs if
the battery isn't overfilled. StuporXtech #1130 01 Dakar Or
- I had a similar event, but the reason the acid came out was because
I dropped the bike in the dirt. BMW replaced the small electrical
component cover on the right side under warranty. I put a tie-wrap on the
vent tube and washed everything with baking soda (had to re-wrap the
negative battery cable). I disagree with the previous post that this bike
doesn't need the tie-wrap. My vent tube was barely long enough to go on
the battery, so vibration probably knocked it off. I suppose you could
argue you are not supposed to drop the bike, and the acid would not come
out otherwise, but on a really rough, steep dirt road it may happen. There
are closed-cell gel batteries on the market too. Rod, CO '02GS
- The acid from my battery nearly ate a hole through my engine cover.
Now I have a sealed Hawker batter :) No more worries. Stumby (DC)
- The vent tube on my 99 came off on it's own, and when I dropped the
bike at one point, acid spilled and trashed the finish on my silver paint
too (I've since had the frame replaced for a different reason). I disagree
that the tube doesn't need a clip...either a clip, or a tighter fitting
hose. mine pushed on and pulled off way too easily. I've since also gone
with a sealed battery. Mark #403
The terminals on the GS come loose easily. Is this normal?
- In off-roading the bikes I definitely have found a
few times the loose connections in the batteries which cause 'mystery'
starting problems. It's a PITA because the covers have to come off, but
fixable/avoidable nonetheless. DHP #711
This battery problem is very common. If you look at the design of the
cables that go to the battery you will see that they have a lever effect
on the fasteners to the side that vibration causes them to loosen. Bad
design. I am sure BMW has seen this problem because all the new bikes
coming through have lock washers taped to the top of the battery as an
after thought. I have installed these lock-washers on my bike and it has
cured the problem. Stuportech
What's the Story with the squashed GS Battery Vent Tube? How do I fix
- I have noticed on many of the F650 G/S and Dakar that
Battery Vent Tube is TOTALLY CRUSHED FLAT by the air intake nozzle OUT OF
THE BOX. Another example of the tight quality control used when producing
these fine bikes. If you own one of these you might wish to check this
problem has been corrected by the person who maintained your motorcycle.
With the location of this battery I wouldn't think battery leakage would
be good. If someone over fills the battery when new with pinched vent
tube. BIG MESS. I have found that if you reroute the vent tube under the
wiring harness and slightly to the front of the motorcycle this problem
can be taken care of. Stuportech
What do I do if the battery terminals break?
When replacing the battery, both terminals partially broke. As I
applied fairly normal torque to both bolts (lubed with dielectric grease,
a little tighter than hand-tight), a side of the circle that the bolt goes
through opened up. In other words, the "O" that the bolt goes through on
the battery now looks like a "C." What's with that?
- That can happen if someone only did up ONE side with
a screwdriver or spanner, without holding the nut on the other side. Know
exactly the story. Happens if you use the "V" the nut sits in alone to
hold the Nut. HOLD the nut WITH a spanner.
Is there any way to check for a DEAD Cell?
- There is a way you can check this VERY carefully,
take off the cosmetic plastic so you can see the battery, remove ALL
battery cell filler caps. IF you have glasses, yep those things that some
of us need to see with :-) They are for protection. Otherwise, WEAR
GOGGLES!. Turn on key, hit starter, while looking at water level in
battery cells. IF one cell bubbles profusely when battery is under load
AND the others don't, THEN that cell is a dud. The battery voltage would
sag badly under load at the same time. Vibration usually is the cause of
cell failure like this. In doing the "cell bubbles check" be VERY careful.
It Can spray out of the cell under SOME circumstances. Jack, GS,
Can you (safely) add water to a charging battery?
- Batteries contain sulfuric acid. Charging batteries
generate hydrogen. One teeny-weeny spark (even static) could easily ignite
the hydrogen inside the battery, causing it to explode (with sulfuric acid
spraying everywhere). I wouldn't consider that safe. Marty #436
How do I clean up acid spills?
- First make sure you protect yourself. Rubber gloves
and eye protection are a good idea. Mix some baking soda and water (1
pound baking soda to 1 gallon water) - add this to the acid spill to
neutralize it. Check for damage to the bike - the acid may have dripped
down onto other parts of the bike.
GS battery check - can it really be that difficult?
I can't find this in the FAQs so perhaps someone can help me out. Is
there a way to check the fluid level in an '05 GS battery without a)
having to remove at least two pieces of cowling and b) remove the battery
from the bike? I tried shining a torch through the battery to check the
fluid level but without success. In theory there is no need for me to
check the levels right now because the bike has just had its first service
- but I wouldn't want to rely on the workmanship - see comment below re
brake pedal. Lep
- Buy a sealed battery... (that's what I did). billmallin
- To get at the battery you only need to undo the six bolts holding
the centre panel. There is sufficient flexibility in the soft plastic side
panels to simply spring the tabs out of the centre panel, with a gentle
bit of wiggling. You don't even need to take off the oil-tank cap.
How do I remove the battery from my CS?
- To remove the battery from the Scarver is not fun.
You have to remove the left ''fence'' (the left thingie you need when you
lock a helmet to the bike, using the ''spider''). You have to remove the
left large side of the bike, the plastic, and you have to loosen the left
- Pull off the rubber belt on the battery, remove -screw, lift the
battery up and remove the +screw, and ta-daaa the battery is out! Keep an
eye on the breath hoose, and put it back where it was when you put the new
- To put the battery in is even less fun, and do not do this
outside on gravel, because I guess you are going to loose screws, and it
is easier to find them inside!
- I bought one of those magnetic thingies that look like an antenna,
to pick up small metal parts; I needed it when I had the battery out last
year! And you need a low blood pressure, and some time, for this job.
Should I grease the battery terminals?
- Yes. Use an anti-corrosive gel, or petroleum jelly (any automotive store has it). Don't use just any ole grease. This will assist in getting long, uniform performance out of your battery. Also, make sure you tighten the connections well.
- A commonly available alternative is Vaseline.
- Another name used is a "dielectric grease".
What if I overfill my battery?
- When you add water to a wet battery cell, you are adding water. When you remove liquid from a wet battery cell you are removing water and electrolyte. This will reduce the charge capacity of the battery. Just leave it - and the battery will sort itself out.
Note: For Quick Direct Access to the Terminals see the GS Fairing FAQ.
Many Charge through the Accessory Plug, but read cautions below.
I bought a new battery. I need to charge it up. What current should I
- The rule of thumb for charging a battery,
particularly for the first time, is NEVER to use a current that exceeds
1/10 of the ampere/hour rating. I shouldnt imagine it is over 25 AH, if
that. What this would mean if it IS that high, is that charging at 2.5A
would be a FAST charge, not a trickle charge. For a 250AH car battery,
2.5A is a trickle charge, not for a motorcycle battery.
Can I charge it through the Accessory Plug?
- Maintaining/trickle charging the battery through the
accessory plug is OK, but not full charging, unless you have a small
enough charger - and make SURE you use a small charger, less than 2
How long should it normally take to charge the battery on a Battery
- For a New battery 10-15 hours on a Trickle Charge.
Fill the NEW BATTERY, delivered dry, with Battery Acid, not distilled
water, that's for topping up. Don't put e.g. a 6 amp Car Charger on it.
You'll fry it. Use a nice slow trickle Charge 600mA e.g. Don't forget to
put Acid in. Otherwise, you'll fry it.
I fiddle with electronics. Is there a Battery charger schematic
My Battery Water is always Low. I suspect the VR is overcharging the
System. Is there a solution?
Can I start a Motorbike with a Flat Battery using a Car Battery?
- Yes, however it is HIGHLY recommended you connect
the car battery with jumper cables, while the car is not running and then
starting the bike. Running the car, when starting the bike, could damage
the bike's electrical system. Using the car to charge the bike's battery
could damage the battery, because the car's charging system will put out
many more charging amps than the small bike battery will accept in its
dead condition, possibly leading to overheating and a ruined battery. It
could also lead to voltage spikes could take out the VR or BMS at the very
least. A reverse polarity hook up would definitely zap the machine.
Adding water to battery. I noticed my battery ('99F) was near the low
line. Should I ride for an hour, or so, to charge up the newly diluted
battery acid, or can the bike sit overnight or for a day or two?
- If the battery was fairly strong before replenishing
with distilled water a few days should not matter. Art #884.
How do I use a Voltmeter?
- See the How do I test it section in the
Do you have any more information on the F's Charging system?
What is best way to make Battery Charging Access?
Do I have to disconnect any battery wires to charge it?
Can I jump-start my bike (without removing the faux tank)?
- On 2004 models there are remote battery
terminals: The positive (+) terminal is under the seat next to the fuse
box - there should be a small red sticker above the terminal, and a black
cover on the terminal. The negative (-) terminal is the strange bolt on
the oil filter cover (RHS).
- If you have an earlier model, you may need to do something like
GS Charging Access. It is not advisable
to use the accessory socket to jump-start the bike: the wires for the
accessory socket are not designed to carry enough current. The accessory
socket is okay for charging as most small chargers only deliver a few
Is it okay to charge the battery on a GS/Dakar/CS bike (with an FI
- I wouldn't expect a problem... as long as you're
using a "smart" charger of the correct size. The "dumb" wall-wart style
could boil the water out of the battery if left connected for long periods
of time. Marty #436
Does an AGM need a battery tender?
- If you buy an AGM type seriously consider investing
in a good temperature sensing, automatic, AGM compatible charger to
maintain it. I read a good article in the Dec. issue of Ocean Navigator
about maintaining AGM batteries. They will probably have the article on
their web site in a couple of months. The gist is that AGM batteries
commonly fail before they should because they are not properly charged.
UNDERCHARGING and overcharging are equally bad.
What is not clear is whether our GS charging systems are getting the AGM
batteries to a full charge. The article implies that many automotive
(engine driven) charging systems do not charge batteries much beyond
80-90%. The AGM supposedly needs the full 100% charge to keep it healthy.
This is true for a conventional flooded cell battery but they tolerate
undercharging longer before failing.
AGM batteries are capable of being charged more quickly then flooded cell
types which is more of a benefit to boaters than motorcyclists. Too fast
of a charge can only happen during the last 20% of charge which is why
conventional chargers are inappropriate.
The article mentions Gel type batteries as well but only in passing. It
sounds like many of the principals are the same. bg #1002
Do I need to remove the little caps off the cells when charging the
battery? (When I was a kid, I remember watching my dad charge his car
battery and he always took the little caps off the cells when charging)
- My dad used to do the same, but then he had an
ancient charger that used to make the electrolyte boil. As long as you
don't put more than say 2 amps through your fine not
'unscrewing-the-caps', but it's wise to check the battery from
time-to-time anyway. Trevor #999
Battery never fully charged?
- If you have left your battery on a recharger of some sort for more
than the recommended number of hours, and the charger indicates the
battery is still not fully charged, you probably need to replace your
battery. Of course before you do that, check for high resistance
connections (i.e. breaks in the wires connecting to the battery
Can the battery system handle a 500mA AA battery charger?
- 500 mA = 0.5A
0.5A * 12V (nominal) = 6 Watts
This is less than one heated grip draws.
- Just don't leave it connected for days!
Can I charge my iPod overnight from the bike?
- Most likely yes - your iPod has a very low draw. Just do not
let it connected for days!
- Motorcycle batteries are not very durable parts and need tender care. The
most likely thing to have happened is that your battery is discharged and
needs to be charged on a small battery charger. A full charged battery
will go flat within 3 months, if it is not charged occasionally by riding
the bike or by using a battery charger. Do not use a charger that is rated
at more than 1.5 amps. It will take at least a full day to fully charge
your battery, if it is completely dead. If you do not have a charger, buy
a "smart" charger that will taper the charge as the battery charge rises
and then turn itself off when the battery is fully charged. Don't forget
to check the battery cables to make sure that they are tight to the
battery and clean any white deposits that may be near the battery with
water and a brush and coat the terminals with a light grease. Sometimes
batteries can fail due to an internal mechanical short or due to deposits
that accumulate on their bottoms, but this is unlikely (although not
unknown) with a new battery. Richard#230.
- I like the Deltran Battery Tender (BT) better than the Yuasa
Charger but it's really a matter of personal preference. A great article
on motorcycle batteries is on the Yuasa web site at:
They both switch between
PEAK and FLOAT conditions which either pumps the battery up or maintains
it at full charge. Either one you'll want to charge then disconnect not
leave it in otherwise the battery will sulfate. I run gel type sealed
batteries which reduce/eliminate this potential problem. I prefer the
Deltran as you can get a portable travel version and/or an international
travel version. While you can equip these with the BMW accessory plug I
always put the direct connect leads on the battery and use these for the
hook-up. David H Park. #711
- I've got 4 bikes in the garage, tightly wedged away so I can just
SQUEEZE the minivan in there during the winter months (I hate scraping
windshields). I bought 4 of the cheapie 1/2 - 1 amp "wall-wart" type
battery chargers from J. C. Whitney. When I put the bikes away for the
fall (minimum 3 months during the winter), I plug one charger into each
bike. If I were to leave them all plugged in all the time, the batteries
would fry (which is why the "Tender" was invented). What I do is to plug
all the "wall warts" into a power strip, and run an extension cord from
the power strip to the garage door opener light. I installed one of those
little adapters that allows you to take power off at the light socket.
That way the battery chargers will only be on when the garage door opener
light is on (usually a 10 minute delay every time the door opens or
closes). Between my wife and myself coming and going, the bikes get about
40 minutes of charging per day. Seems to be about right. This approach
saves (1)battery removal (2)remembering to plug it in and unplug in a
timely manner (3)shuffling one battery Tender among 3 bikes in the cold
(the 4th is 6V) (4)the expense of owning 4 battery tenders. Downside is
lots of cords strung across the garage (definitely not UL-approved!), but
not a problem since nobody spends any time there in the dead of winter.
We'll see how this system works with the new AGM battery this winter.
- I have a Battery Tender for bike batteries and a bigger charger
(somewhere) for cage batteries. What is it that the Tender supposedly does
or does not do that is not good for sealed batteries? I mean... the
charging system on the BIKE doesn't know the difference. The upper limit
of the charging system SPECIFICATION for the F650 is 14.75 V. So much for
a sealed battery's sensitive self. And if your VR needs flaying, the
battery might see 15.5 V. Flash 412 (CO)
- I use a Battery Tender Plus. So far, so good, no problems.
- My Battery Tender Plus works fine on the (easily accessible)
sealed battery that came with my Yamaha YZ1. Richard #230
- It occurred to me that Tender might have a web site, and indeed
they do. Not sure why I want the "Plus" model, but I do see the "Jr" model
works for lead-acid OR sealed. Below is some info:
OK, this is the deal on sealed batteries and "regular" chargers. The
Tender web site
provides further info on the "Plus" model. Sounds like my
BMW dealer, and the battery shop, are misinformed after all. "NOTE: In
recent years, the Sealed, GRT (Gas Recombinant Technology), AGM (Absorbed
Glass Matte), Lead-Acid battery has enjoyed widespread acceptance in a
variety of applications traditionally dominated by flooded battery
technology. The Battery Tender Plus battery charger circuitry provides a
superior configuration to accommodate the more demanding recharge
requirements of this superior battery technology. Although the original
Battery Tender battery charger will recharge AGM batteries, the full
recharge time is longer than with the Battery Tender Plus battery charger.
This is because of the different implementation of the absorption charge
mode between these two chargers." Those differences are spelled out in
detail in other documents on the website. See Utility / Frequently Asked
The main (practical) difference between the Tender "Jr" and the "Plus" is
that the Plus will charge the AGM's faster than the Jr. It will also
charge an un-sealed battery about 4 hours faster (6 vs. 10 hours to
initial peak of 14.4v). It is always interesting to read the
manufacturer's data sheets, then talk to a dealer to see just how much
they don't know about the product. Today I heard the following:
- HD dealer: "The only difference between the "Plus" and the
"Jr" is that the Plus will shut off when done, while the Jr will run
forever. " NOT! Both slip into a float/maintenance mode.
- BMW dealer: "The Tender brand will not work on a sealed
battery." WRONG, wrong, wrong.
- Battery specialty shop: "Off-the-shelf Tenders will not
work with sealed batteries because they have excessive voltage (greater
than 13.8v); OUR version of Tenders have a SPECIAL CHIP added to them at
the factory that keeps the voltage below 13.8v for sealed batteries." WOW,
good one . . .
I bought a copy of the "Jr" tonight and as I type this note it's merrily
charging away. Or, at least the little red light is on! Scott, ID
- Apparently (See the Battery FAQ for more details) Sealed AGM
Batteries have a HIGHER charging capacity than Unsealed ones. So anyone
with VR/Overcharging problems will be better off with one of those, on a
Tender, even a cheap one with no limiter ... ;-)
- 14.4V is the usual design limit for 12V vehicle systems, at 14,8V
the charging turns into electrolysis, and wrecks the battery. A battery
that can't handle 14.4V shouldn't be in your bike, but there are plenty of
sealed batteries suitable. rakaD.
- Battery/Charger Tester. This weekend I received the Harbor Freight
Tools Battery and Charger Tester that I ordered on sale for $20. It took
two weeks and I mailed my order in. This thing is fairly substantial and
consists of a voltmeter mounted to a large vented steel box in which are
some very heavy wires about a quarter-inch thick that apparently are
designed to get hot, like a toaster oven. Two large battery clamps are
attached to the side of the box. You attach the big clamps to your little
motorcycle battery (this thing is designed for car batteries), read the
voltage and flip a switch for 10 seconds. This places a 50 amp load on the
battery and heats the internal wires. You then read the voltage again and
if it is in the green, your battery is OK. If not, there is some sort of
problem. To check the charging system, you just connect the clamps to the
battery while the engine is running and read the voltage (no wire heating
this time). If it is between 13 and 15 volts your charging system is OK.
Not too high-tech, but it seems to be worth $20 (or even the normal retail
price of $28). It uses a real meter, none of that fancy digital stuff
here. Richard #230: 1997 Funduro, 2002 R1150R, 2002 Yamaha YZ1, 1993
Honda CB750 - Pacifica, CA, USA
- The BMW shop here pushes the "Accumate" charger for $59, claiming
it works for lead acid OR sealed batteries; this is why I DON'T want to buy the
Tender, according to them. But I was thinking I could spend less than $59
for on a 1-2A charger. I just called a local battery shop and it turns out
that maybe the dealer could be right after all. The battery shop guy said
they have the Tender for $30, but that I can buy one for under $20
somewhere else. The difference (I think I got this straight): Deltran, who
makes the Tender for Hawker, will put a limiting chip inside the Tender
for a few extra dollars. This chip limits the charge to 13.8v, which is
the cap for a sealed battery. A "regular" Tender will cutoff at 14.5-15v,
which is OK for a lead-acid battery. He said the sealed battery is VERY
sensitive to excess voltage. I don't know if I'll ever buy a sealed
battery, but maybe I'll bite on the modified Tender that works either way,
just in case I get tired of checking water levels. Scott, ID #1244
- I have a Battery Tender for bike batteries and a bigger charger
(somewhere) for cage batteries. What is it that the Tender supposedly does
or does not do that is not good for sealed batteries? I mean... the
charging system on the BIKE doesn't know the difference. Flash 412
- I use a Battery Tender Plus. So far, so good, no problems.
- My Battery Tender Plus works fine on the (easily accessible)
sealed battery that came with my Yamaha YZ1. Richard #230
- It occurred to me that Tender might have a web site, and indeed
they do. Not sure why I want the "Plus" model, but I do see the "Jr" model
works for lead-acid OR sealed. See http://www.batterytender.com/.
They Note: NOTE: In recent years, the Sealed, GRT (Gas Recombinant Technology), AGM
(Absorbed Glass Matte), Lead-Acid battery has enjoyed widespread
acceptance in a variety of applications traditionally dominated by flooded
battery technology. The Battery Tender Plus battery charger circuitry
provides a superior configuration to accommodate the more demanding
recharge requirements of this superior battery technology. Although the
original Battery Tender battery charger will recharge AGM batteries, the
full recharge time is longer than with the Battery Tender Plus battery
charger. This is because of the different implementation of the absorption
charge mode between these two chargers. Those differences are spelled out
in detail in other documents on the website. Cheers, Scott, ID '02
- Battery Charger Optimate III - On board
- I don't have any knowledge or experience with the charger OPTIMATE
III, however, I do have a "BATTERY TENDER" charger. I have used on a '86 Honda
V65 Magna, '01 R1150GS, '02 K1200LT, and it has worked fine. I will be
picking up my new F650GS Dakar this weekend and plan on using it on that
bike as well. The 1150GS and K12 were charge through their accessory
outlet plugs that came standard on the bikes. On my new F650GS Dakar, I'm
having two accessory plugs installed for heated vests for me and my wife
when she rides along, and will use one of them when the bike is parked in
the garage to keep the 'BATTERY TENDER' plugged into. All have been
connected to the charger while still connected in the bike without adverse
effect. The "Battery Tender" and probably the OPTIMATE III as well, are
made to produce a 'trickle' charge with a sensing circuit internal to the
charger that will keep just enough charge on the battery to keep it at
peak charge. Once the charger senses a full charge status on the battery
it will just sit there in a monitoring mode until the battery voltage
drops, then will start a trickle charge to regain the battery. Input to
the 'BATTERY TENDER' charger is 120VAC @ 60Hz, 24W. Output is 12VDC @
750mA. This model of the 'BATTERY TENDER' is very small, resembling the
type of transformer you plug into a wall outlet to power up such items as
a answering machine/phone. So really nice for packing along, or storing.
Your OPTIMATE shouldn't be a problem at all. Have connected the accessory
plug on the right side (flank), and it is connected directly to the
battery. Blue '03 F650GS Dakar, Washington State.
- I also use the Battery Tender, I connected a Gerbing heated
clothing plug directly to the battery, when not being ridden, I plug in
the tender. The Gerbing plug wire is fused with a 15w fuse accessible on
the 650 gs. billbotoo
- I use the original Optimate on my Moto Guzzi and the Optimate III
for my CS. I merely plug them in at the end of every ride and forget them.
Often, I leave one or both bikes for weeks without using them. The 'battery
conditioners', as they are known, have worked without problem for many
years now on a variety of bikes and there does not seem to be a
disadvantage as far as I can see. I keep an eye on battery water level but
this has never fluctuated. The batteries are kept in tip-top condition and
allow first-press starting (or first kick for the Guzzi ...) every time.
This was especially useful when I had the R100R and needed a reliable,
early winter morning no-fuss start. I recommend the Optimate III without
hesitation for the F650 range, based on my own experience. Keith,
- Have used an Optimate for years on XS1100, R100RS, XT500 (kick
start but always started first kick - yeah first kick!), R45, DR350,
R1100RT, Dakar - all without problem and especially good in the winter
when the bikes are cold and need a healthy battery (especially the
R100RS). Have two leads for mine; one with the 'cigarette lighter plug'
for the socket on the Dakar and one with 'crocodile clips' for the DR.
Plug them in and leave them. Mike, London, UK -- '02 Dakar -- '98
- Many of us have wondered how long it takes to charge up a battery,
particularly when it is in the bike. We have also wondered how much juice
is grabbed from the alternator to charge up the battery. I lifted this
response from the R1150R web site, and while it discusses the R-bike and
its 700 watt alternator and 19 amp battery, it is still interesting. I
don't know if the information is correct, but it sounds right to me: No
amount of charging or riding the bike will bring that battery back 100%
from it's impending certain death. It's too late for that scenario. It
didn't die, it was murdered. If it's just a month of on the centerstand,
the time to full charge should be about 1 hour of continuous running.
Unlike battery chargers that have a fixed low output, the Beemer's
alternator will maintain 14 volts from the start. On a "low" battery, that
associates with a 10---15 AMP charge for the first few minutes. Then the
batteries Amperage draw slowly tapers off to 2 or 3 Amps, after 20
minutes, as the battery's charge deficit is replaced. To achieve 100%, a
lot of time is required, as the closer you get to 100%, the slower the
percentage approaches 100%. All the while, the voltage regulator maintains
14.0 Volts no matter what RPM. The 50R 's alternator is so powerful
(YEAAAH!!!), you'll get at least a 10 Amp charge at an idle, if your
battery is pretty low, as soon as you come down with the start lever. In
this infrequent riding season for everyone in the Northern Hemisphere, use
your bikes running time wisely. Put the longest part of the ride at the
end if possible. Never start your bike to move it 30 ft (9.1M) to the
garage/shed, only to let it sit for a week++. That practice traumatizes
batteries. Ride it to it's final stop the first time -or- push it there.
Most of the battery sites have excellent FAQ sections on battery care. Try
- The origional Battery Tender (now discontinued) was designed for
wet cell lead batteries and is not adequate for AGM of Gell Batteries. The
AGM model which is the Battery Tender Plus works with AGM and with the
origional wet cell batteries that come with the F650. The Hawker battery
is an AGM Battery. To follow up RE: Battery Tenders the following was
e-mail sent to me when I inquired about the proper Battery Tender to
"The Battery Tender Plus was made in two models. Part # 021-0156 is the
one made for gel batteries which BMW installs in its motorcycles. Part #
021-0128 is the model for AGM batteries which Harley installs in their
bikes. The gel model charges a little slower and lower and if you use the
gel model on the AGM batteries then you might not get a full charge. If
you use the AGM model on the gel you may damage the battery.
It is true that the part number is not displayed on the Deltran Battery
Tender or the BMW version of the Battery tender. However the one for gell
cells has "Gell Cell" printed o the front of the case. The Battery Tender
Plus is the one for AGM Batteries. The Battery Tender Plus that has for
"Gel Cells" printed on the front of the case is the the one for Gell
Cells. the BMW charger for gell cells also has "Gell Cell" clearly
displayed on the front. do not use the origional Battery tender on the AGM
battery. The origional will not bring an AGM battery up to full charge.
Is it true to say the Voltage Regulator (VR) will be stressed and
eventually fail if the battery is not kept topped up? For more information
on the Voltage Regulator, see the
Voltage Rectifier FAQ.
- Eventually? - sure. But considering that we don't
know exactly how our VR (we should probably call it a VRR or RR - UFO
-unidentified frying object, whatever) is designed or exactly what is
inside it, it's hard to say exactly. What you say would be very true of a
more conventional VR, which varies the alternator output by controlling
what it does (with an exciter, field windings, brushes, more complex
parts). As far as I can tell, our VRR/alternator set-up is different than
most systems - I think our alternator runs full out (100% output) all the
time (bad for gas mileage) into the VRR. The VRR decides what to do with
the power - send some of it out (or all of it out) into the battery and
bike system, or send the excess power into an internal resistor (which
burns it off as heat), OR possibly (internally) disconnecting one of the
yellow alternator wires. I can't say that a low fluid battery is good, or
indifferent, for our VR. I'm sure it must stress something somewhere in
the VR and wiring system. I just don't know exactly what/how. Obviously
completely dry is bad, but that's an extreme.
Is the converse also true that a failing VR will empty the
- Summary: depends. :-) If the VR (RR, VRR, whatever)
fails into high output mode, absolutely yes. But it is a complex unit and
could probably fail for several different reasons, so it could also fail
low, undercharging, or fail dead. Possibly it could fail high, boil out
the battery, and then burn out and fail dead. I suspect that one reason
for our low battery water occurrence is that many of the VR's charge too
high - like mine at ~15volts. That's not necessarily a real failure,
probably just crappy Quality Control. For some once a week riders on short
trips, 15v might be just fine. For high mileage riders trying to make 1000
mile trips each week, that would be bad overcharging for the battery.
Can I disconnect the battery while the bike is running?
- One thing for sure, in almost all solid state
(Transistorised) VR charging systems, if you remove or disconnect the
battery while the system is running, you almost always ruin something
expensive in the VR! Don't ever do it intentionally in your car.
When I try to start my bike IS the Tic Tic Tic sound coming from the
Solenoid, (Large Round Object just Rear of the Battery on the
Cover with two big red wires coming out of it) symptomatic of a Flat
- Yup. It's the solenoid trying to close, and not
quite having enough voltage to stay closed. It cycles back and forth when
it doesn't have the voltage. Not good for the contacts either, can arc and
overheat, melt a few things if you do it too much. See also the Noise 8 in the Strange Noises
My bike will not start. When I turn the key to the on position, there
is a buzzing sound... Turned the key off, no buzzing, turn it back on
without touching anything and it is back. Push the starter button and the
buzzing stops and the lights dim.
- What does your Voltage Meter read when trying
to start (starter button mashed)? Read voltage directly from battery
terminals. Then read voltage between starter motor and ground while trying
to start. Remove the cables from battery and clean them up. Reinstall and
try again. Watch VM. The above will probably tell you a lot.
It's possible (kind'a long shot) that the low voltage from the first
attempt has welded or otherwise bunged up the contacts in the circuit.
More likely, the buzzing sound you hear is the relay not getting enough
juice to stay closed, turning it into a buzzer. jetdocs550
- First, check the battery. Second, toss the battery.
Third, replace it with a new one. Or just skip to step three. SScratch
- Solution. Well, off to buy a new battery. Tested battery
with key off, 12V no problem. With key on dropped to 4V. With started
pressed it dropped to 3V. Could have sworn I tested it with key on last
night and got 11.9V but it was late....
I'm having problems starting the bike. Could it be the Battery?
- Check your battery water level. If it is down, you
may have a battery with a bad cell. If the battery is not replaced, it
might take out the voltage regulator. Check the cells with a hydrometer
and check the voltage across the battery terminals with a volt meter. All
cells should have an equal charge and voltage should be limited to about
14.5. If one or two cells have a low specific gravity, replace the
battery. If the voltage is higher than 14.5 volts with the engine running,
you may have a bad regulator or stator and not replacing it may even cook
a new battery. A battery with dead cells could most certainly cause it to
stall out at idle. A battery with dead cells is flaky at best, and if
there is not enough voltage to operate the ignition system, the engine
quits running. You are also not doing your charging system any good by
operating on a near-dead battery.
- [After chain replacement on a 97 F650ST] Might be
worth looking to see if the countershaft cover "pinched" the ignition
ground wire that comes down alongside the oil filter cover. I have to
assume that the cover was removed and replaced to change out the chain.
Also, LOOK at the battery water level, check the battery connections, and
don't forget to check the position of the "engine cut off switch."
- See also the
Hard Starting and Poor Running
My ABS light came on while riding and stayed on. Now the bike won't
- If your ABS light comes on while riding, it can be
due to battery problems. The ABS system requires a certain ammount of
power to operate. If there is not enough, it switches itself off. If you
are riding in cold weather, and / or have lots of accessories and your
toaster plugged into your bike, try switching a few things off and ride
for a little before stopping. Otherwise you may not be able to start the
bike after turning it off. If you can not start the bike, check the
battery levels, and pop it on the tender (assuming your at home).
Stalling, difficulty starting and hesitation when applying generous
Can a battery get too weak to start after only 12 days of non use
except for a quick 10 sec. start to move to from the driveway to
I ask cause I just came back from a quick night ride. I haven't been
riding and was wired. Figured I was due a short ride before I went to bed.
Anyway my bike wouldn't start. It kept cranking but wouldn't catch. I left
it for about 10 seconds then tried it again and it finally turned over.
They way it sounded when it turned over is like like it was almost at the
brink of turning over then it just caught. Sorry I can't explain it any
better. Oh yeah...The bike is only 3 months old. That is why I am
surprised. Should a battery tender be purchased in my near future?
- If you have an alarm running 12 days may be enough
to drain the system. The short run takes a chunk out of the stored power,
the alarm drains a bit more and the battery won't give any current. I
doubt this should be the case. Turning but lack of spark is an ignition
rather than battery problem. A flat battery will either click the starter
relay and do nothing or turn the engine lethargically until it dies. Check
the battery voltage (engine off) flat (11.8 ish), charged (12.5 ish) and
engine running (14 max). Given the age of the machine, I'd say BMW owe you
a battery and maybe a voltage regulator. If they change the VR you want a
battery too. If they change the battery, check the date of production and
get them to give at least a 12 month warranty for your bikes use (they may
try and call it a consumable and not cough up when the VR boils its
fluid). Battery tenders are great, but you need to be careful still. Get
the tender and a timer plug. Use the timer plug so the tender only comes
on 1 day a week. If you leave the tender plugged and powered, it will hold
the battery at 12 volts plus rather than cycling low and high. A "trained"
battery will then fail to push a current without this higher voltage.
Andy Leeds UK #982
- I agree with most of the comments (not sure about
warranty coverage - good luck), but one aspect was not covered. You say
the bike/battery is only 3 months old, and the bike was parked for 12
days. The 12 days parking shouldn't be too bad as long as the bike was
above freezing (and it's summer, right?), but how often or how many miles
did the bike run in the previous 3 months? If it was a new battery, most
likely undercharged by the dealer (as others have pointed out), and you
only had 900 miles of charge time in the 3 months of ownership, and then
parked it for 12 days....likely the battery was not well charged to begin
with. If you started it up slowly, with the headlight on for a minute
before starting (as you have to do to cycle the computer), the headlight
is a large drain on the already weak battery. If I had to start the bike
with a weak battery, I think I'd try to reach up and unplug the headlight
before starting, it might give you a little extra juice. (Not sure how
difficult it is to reach the GS headlight plug, but it's easy on the
Classic.) Yes, I realize (on the GS, unlike the Classic) the headlight
relay cuts out while actually starting, but I think not while the bike is
waking up while you cycle the computer. That could be 30-60 seconds of
drain on a weak battery. Do not drain the battery and recharge it - lead
acid batteries do not do well under those conditions, you are thinking of
NiCad batteries that must be cycles up and down. Different animal. A
battery tender will help. Todd #389
If I've allowed my Battery to Drain Water/Get Low (Due to e.g. VR
Problems, Poor Maintenance), will it ever fully recover?
- Keep an eye on your battery, even if everything else
checks out OK (you DO need to the check the voltages) keep in mind that
you have just brutalized your battery and it will never fully recover, so
expect to have to keep a closer watch on it. Todd #389
- Once you've let a battery go flatline, you've seriously reduced
the life of the battery. Follow that up with 2 or 3 weeks to croak all
over again, and you're set. Sadlsor #1444
Ever heard of a sudden battery failure? Sudden Battery Death? Battery
- Yup. My R80G/S started up just fine one morning using the electric
starter. At lunchtime, I went to run a couple of errands. Three stops and
three starts with no problems. Sitting at a stoplight, idling, it burped
and died. Refused to crank. Pushed it over to the side of the road to
trouble shoot. Eventually, I figured out that I had neglected the battery
too long. Topped it up with some distilled water. Roll started the bike.
Had to roll start it at work, too. Got it home and found that a cell was
D-E-A-D. Flash #412
- I am in Mulhouse, France and yesterday I had my first breakdown.
Yesterday I was riding on the Autobahn in Germany when I after several
stops stopped for gas (the third time that day). I turned off the ignition
switch and filled her up. After I had paid the gas, the bike wouldn't
start at all. The neutral and oil light on the dash board didn't light at
all. A friendly German helped me to start the bike by using starting
cables and we connected his car battery to mine. The bike started right
away. When the bike was at idling one could see that there was no power in
the battery, since the neutral green light and the front head light was
rising and falling in strength. I continued another 200Km to my
destination. When I arrived at the destination I had still no power in the
battery. The bike is performing as usual except for the starting
- The battery is new and has only been used for 10 days or
so. The water level is at the high mark.
- The VR tested OK last week. It tested about 14.1V at 1500
- Yesterday I drove at high speeds ~130km/h for long periods
~700Km. I used my Aftermarket heated grips a lot. I used it many times in
the start-up mode (60W, max time 5 minutes is stated on the switch). After
the breakdown I switched the heated grips off.
- I don't have any more electronic accessories, except for
a accessories connector.
I am going to buy myself a multimeter and starting cables this
afternoon (some of the things I didn't thought would be necessary on the
trip...) and measure the battery, which is charging right now. I have just
printed out the Electrex fault finding guide, and will start with that
tomorrow or on Monday when the battery is fully charged.
I am thinking that it can be one off the following reasons for the
- Faulty Battery (unlikely since it is new).
- Faulty VR (possible)
- Faulty Alternator (never heard of an alternator going bad,
so I don't know)
- Something (heated grips? or else?) is drawing a lot of
I have done some more testing today and it looks like it is the
battery that is bad. I charged it over the night and put it on the bike
this morning. Nothing happened. No power at all. After checking some
cables I connected a friends car battery to mine. With this connection the
power is back and the bike starts. However as soon as I remove the
connection to the car battery the voltage over the mc battery drops to
3-4V. If I remove the mc battery and just use the car battery everything
is fine. Including the VR which measures 14-14.5V at rpm from 1500 to 6000
in this mode. Another thing I noticed is that when I try to charge the mc
battery the voltage rises to 14.8V, but the current is only 5mA, when it
should be 500mA. Well as far as I can tell it is the battery, but why is
it already toasted? It is only 10 days old. Did I just get a bad battery
or is there something else that is ruining it? Tomorrow I'll see if I can
get hold of a new battery. I'll check back then to report.
Finally: All motorbike shops are closed on Mondays for some reason,
but I found a Battery at a auto accessories shop. I have put it on charge
now and YES it takes a charge. It charged 0.4A when I started, and was
after 2 hours down at 0.36A or so. I'll charge it until I leave for Geneva
tomorrow. In Geneva I'll spend a week visiting a friend and do some
daytrips around Switzerland. I'll keep a close look at the Voltage in the
next few days. The lesson learned I guess is to install a voltmeter on the
bike. I do that when I return home. Perhaps it could be mentioned in the
Battery FAQ, that it happens that batteries are bad when one buys them and
can fail pretty quickly...Another thing one can have in mind when one
doesn't have an multimeter is that the charger (at least mine) gets hot
when it is charging successfully. That way one doesn't have to measure the
current to find out. I checked the new battery today after riding 300Km
yesterday on highways through Switzerland to Geneva (where I am going to
spend the weekend). The ride was good and I didn't experience any problems
with the battery. The DCV measures today 14.3-14.4V, which I think is good
(I have flayed the VR before). Regards, Spakur #1117, Icelander in
Malmo, Sweden, 1995 Classic Red F650 with 65.000+ KM
- I've seen new batteries which would not take a charge. Get a
statement from a local dealer or service shop that your battery IS bad so
you can collect the money from the seller. Hey its probably the least
hassle thing to go wrong in the electrical department. Just make sure
before heading for remote parts that everything is OK. Good luck and good
trip! echo, F650GS Dakar, Camden, New Jersey.
- After you put the New Battery back in CHECK the Voltage again. IF
The VR went bad that MAY have been the reason for a toasted battery. Just
so you don't get stuck in the next town with another dead battery! btw
echo's right. I hade TWO batteries that didn't take a charge. Filled them
up and put them on a charger and 12 & 24 hours later DEAD!. No Charge. The
3rd one worked. Kristian#562
Pop! Smoke! Dead Dakar! - (battery area - anybody had it happen?)
- Sounds like it might be the same issue several
Inmates have had of the wiring harness wearing through. Marty
- Not to throw out the proverbial red herring, but on
the Blackbird that phenomenon was spelled v-o-l-t-a-g-e r-e-g-u-l-a-t-o-r,
as in FRIED. Sadlsor #1444
- Have you checked your battery drain tube to make
sure it hasn't come off and let acid dribble onto the harness? That will
do it and has on several bikes. You may have to pull off the snorkel and
maybe some radiator shrouds to see it. bg #1002
- Solution. Or, maybe it's just a loose battery
connection. I've seen that happen on trucks, when you hit the starter
everything goes dead. Tighten up the terminals, and everything works fine
again. Something easy to check first, anyways. And, when your in there,
you can look for any inappropriate melting... dmemt #1464
Is it possible for a brand new battery to go bad, or might there be
another reason like a short somewhere?
- Yes to both. Marty #436
- Connect a multimeter set to 20 volts DC scale, across the positive
and negative terminals of the battery. you should see about 12.5 volts or
so. Next, turn on the ignition and recheck voltage.....it will drop maybe
to about 12 volts. Press starter button, the voltage reading will drop to
about 11 to 11.5 volts WHILE cranking. IF the voltage reading goes down a
mineshaft, then you have a bad battery, if not then you have a possible
wiring/switch/solenoid problem. jack
My bike is dead (no headlight, brakelight etc), but a multimeter shows
the battery is good.
- Remove the wires from the terminals, clean the
battery terminals and wire terminals until they shine. Take a look at the
level of electrolyte in the battery and if it is not between the lines add
DISTILLED WATER. Reassemble and try ignition again.
If it still won't start, get a meter. Set the meter to read voltage. Read
the voltage on the battery, ignition OFF. If it says less than 11 volts,
you may have a dead or bad battery. First try putting it on a charger for
several hours. Repeat this test. If it is STILL below 11V, you have a BAD
battery. Replace it. (They're about $25 at Sam's Club or WalMart. Check
the FAQ.) Otherwise...
Turn the ignition on and read the meter again with it on. If you lost
three or more volts, you have a BAD battery. Replace it. Flash
- Solution: I pulled my battery and confirmed that it was
low on water. Instead of filling it, I took it to my local dealer and had
them check it out. The guy tested the battery and he also was getting a
reading on his meter. So, the battery had enough juice to register a
charge, but not enough to start the bike. bsktbee [Ed Note: This
most likely would have been identified in the above answer]
- See also the Hard
Starting and Poor Running FAQ
What are the normal voltages of the battery?
- This depends on many different things. For example,
if you do a lot of short trips with heated grips and high beams on, then
your voltage will be lower. Do you leave the bike on a battery tender?
What sort of battery do you have? etc...
Generally to measure the battery voltage correctly, you should not check
it immediately after riding. Give it a few hours for the battery to reach
room temperature. The voltage reading will depend on many factors, so
check it regularly so you know what is normal. Keep records, so when it
does change you know there is something wrong!
When the bike is running (rev the engine to 3000rpm, turn off all
accessories) you should see about 14.5 volts at the battery. Take the bike
for a 10 minute ride and then check the voltage again. A drop in voltage,
or high voltage could indicate a failed VR. Based on comments from
Richard #230, mark #403
(See the VR FAQ)
Battery life when riding short distances?
- The life of your battery depends on several factors
including its charge state, how often you recharge it, and what
accessories you use. If you are riding lots of short distances the battery
may not have enough time to recharge. You have several options: try using
fewer accessories (turn off your fog lights and microwave five minutes
before arrival at your destination) or better yet
ride the bike on longer trips. Failing that you could try keeping your
bike on a battery tender each night.
See also Battery Life.
Can a battery tender "boil off" a wet cell battery?
- I hooked up my wet cell one night and it started to
gurgle almost right away. I didn't think much of it and opted to rely on
the float feature to turn off the tender when the battery reached an
optimal charge. I guess it never did. In the morning, the charge light was
lit but it wasn't gurgling. I thought, "OK, maybe the light is broken.
I'll check it after the Mardi Gras Rally."
I fired up the bike and flogged it for a couple hundred miles to just
north of Lake Ponchartrain. I ran my aux lights the whole way (oh, and my
Scott's oil filter, too. There's no relevance there but I thought it
really important for you to know). I shut the bike off and fell asleep at
the Crack House on Lake Datgurlneesumbeeds. In the morning, my bike
wouldn't start. I peeled the hide off my bike and checked the battery. It
was bone dry. NothingClever #1441
What would cause a battery to bulge?
- (for a conventional wet cell battery) Only two
things I know of that will "bulge" a cell; freezing or frying. My guess is
the cell is shot. Do you use a tender? They are great for covering up bad
cells... for awhile. I'd also suggest you consider an AGM battery upgrade.
No acid spills and more capacity. dmemt #1464
- (for an AGM) Just replaced my AGM battery (in a
Classic, 2.5 years old) - while I was doing my service, I saw the telltale
sign of a bolt covered with that white powdery stuff caused by leaking
battery acid. Sorry - when they get a bulged
case that cracks, they "seep". What caused it to bulge? Got me... typical
voltage regulator overvoltage (common to Classics - see VR FLAY in FAQs)
or a combination of high mile days across the Great Plains in 100F+
weather in conjunction with the location nearly atop the muffler pipe?
Do I need to do the Flay to keep my new battery in good
Can I remove my Battery while the bike is running?
- There is a long and detailed discussion on this
however the short answer is NO, it is not a good idea and could lead to
all sorts of damage to your bikes electrical system. In otherwords - if
you choose to disconnect your battery while your bike is running, do so at
your own risk!
GS clock reads funny when inserting a new battery?
- If you GS clock reads funny when you insert a new battery, check
the voltage on the new battery. It is probably low.
Getting Home With a Dead Battery
- I talked to a local dealer here in Geneva and he stated
that if the battery is dead on a GS, it isn't possible to get back home. This he said
was because of the F.I. The classic will however get you home. Is this
correct? Regards, Spakur #1117, Icelander in Malmo, Sweden, 1995
Classic Red F650 with 65.000+ KM
- I believe that statement may be true, Spakur. My understanding is
that BMW FI computers must be supplied with a certain level of voltage or
they will go on strike. If the voltage into the computer is either too
high or too low, the thing shuts down to protect its small brain - leaving
you to push, if you want to get down the road. I am not sure if the
Classic can run with a completely flat battery. My experience with my
Honda Nighthawk (which certainly is no more hi-tech than the Classic) is
that when the battery dies, the bike will not start without being jump
started from an outside source. Push starting will not get it going. Once
started, it will keep running as long as you keep the revs up. Let them
fall to near idle and the engine dies, leaving you stranded again.
However, if the failure was due to a fried VR, you might be risking some
of the bike's electrical components by running it that way, as the high
voltage may fry something. Richard #230: 1997 Funduro, 2002 R1150R,
2002 Yamaha YZ1, 1993 Honda CB750 - Pacifica, CA, USA
- My vote is the dealer is wrong. Wrong in the sense that the
engine should start with a jump and run on the current produced by the
alternator. That's what it does even if the battery is good. You cant
start the engine by bumping it into gear on a coast, but you can jump it.
You cant roll start my ST1100 with a dead battery either and its
carburetted. Why? There must be some exciting current flowing through the
coils for the alternator to produce electricity. That may also be the case
on the GS. echo. F650GS Dakar, Camden, New Jersey.
- There must be some exciting current flowing through the
coils for the alternator to produce electricity. Nope. Unlike
alternators with excited fields, our alternator has permanent magnets. You
move any wire (circuit) through a magnetic field and you get current flow.
Excited field alternators are MUCH more efficient than permanent magnets
ones. The VR is used to control the current to the field. Essentially, you
turn OFF an excited field alternator when you don't NEED the power.
Permanent magnet alternators run full blast all the time. Burning gasoline
to produce electricity you have no capability or intention of using which
then MUST be turned into heat that must be dissipated is NOT the most
efficient use of fossil fuels. Permanent magnet alternators are cheaper to
BUILD. Excited field alternators are cheaper to RUN. Flash 412
- If your battery is more than 3 years old, you might find a newer battery a
bit more tolerant of overcharging, even if the old battery is perfectly
good. Todd #389
- The battery of my F650 "Classic" lasted at 7 and half years. Batteries
have a life time and the minimum is about 2 years. Fede
- I mistakenly unpacked my battery and filled it with acid, before I
realized that the battery in my bike just had loose connections. I have
been charging it for the past year, waiting for the original 6-year old
battery to expire, but it just won't die. Richard #230, Pacifica, CA
- Mine is 30 months old, 13k miles. NormJ #473 Seattle
- PS the OEM battery lasted 25 months and 45,000 miles +, I would have
expected the OEM to last longer since I rode the bike a lot and kept the
battery charged. davemishalof, Inmate # 717 - '01 F650GS
- Like Richard, I am still running the original battery on my 97 with no
flaying or mods of any kind. I think the secret is that I commute 40mi.
every day, year round when there is no ice on the roads. Letting them sit
around unused seems to kill them. I also have never let the water
(distilled) get low. I admit that this is the longest I've ever had a
battery last and still work like new. (now I've tempted the gods -next
time I hit the starter button you know what's going to happen) Mcguiver,
16 Oct 2002
- I can't brag about my original Japanese-made battery anymore. It bit the
dust this weekend, after going 6 years and 30,000 miles. I should have
knocked on wood last week when I again told someone how long my battery
was lasting. Anyone want to bet that its American-made replacement won't
last that long? Richard #230
- Never brag about stuff---it immediately results in whatever you've been
bragging about going "belly up." Oh Bummer! I just bragged about my
beautiful mother in law.
- Battery died at young age. Yup, this tragedy happened right here among us.
At the tender age of 2 years and 2 months (roughly speaking) and 14500
miles, my battery went out without any warning. For the record / FAQ /
other people to keep in mind:
its_xls, 2001 F650 GSA -- San Jose, CA.
- There was no warning whatsoever, the battery went flat during an
attempt to start the bike. Previous starts showed no problem (no slow
cranking, weak lights, etc). During that last attempt, it cranked for a
split second, then the lights on the "dash" went dim. After that no more
- Jumper cables hooked up to the battery -> Could start the bike and it
runs fine as long as the jumper cables are connected. Disconnect the
jumper cables (even with engine revs ~4k) and the engine dies immediately.
- The voltage was very low (ignition off - ~9V, ignition on - ~4V).
- Dealer claims the battery did not accept any charge at all (which I believe).
- Some of the cells were low on fluid, even though I had topped it off
just about 500 miles ago.
- Having the battery replaced by the dealer is very expensive. I really
suspected something else because of 1), 2) and 5) and thought everything
would be covered under warranty. So if you have the same symptoms, check
the battery first.
- This was probably a case of a battery that was not constructed properly at
the factory. Some Yuasa batteries have been noted for having weak
connections between the cells. When they break, they do so suddenly and
one of the cells fail to take a charge, while the others get overcharged
and then fail too. Hopefully your next battery will not have this problem.
One of the new "maintenance-free" batteries may be the way to go for a
replacement. I haven't heard about any similar problems with sealed
batteries - yet. Richard #230: 1997 Funduro
- Same thing happened to me. Steve#417(in,us)
- About your battery problem I've experienced nearly the exact same thing,
and I actually ended up several thousands of km from home with a wrecked
battery as well as a toasted generator. >"The water level is at the high
mark".< The above may have been your problem.
This short circuit will lower the battery voltage and fool the regulator
not to limit the charge, which will be brutal enough to eventually kill
any remaining cells. Spakur
- At first the level is at max without any bubbles in a cold battery.
- Then the battery warms up and bubbles appear due to charging, this makes
the acid level rise.
- Finally acid exits the cells and if the drain is jammed for instance,
acid will interconnect some cells, causing a short circuit.
- At first I was about to tell you that the cells are sealed from each other
BUT, with the common vent system they are not. I will investigate and test
this with a battery I have, where the one of the pole connections are
damaged. (I had planned to repair it and keep it as a spare, but it is
more valuable as a test item. The ventilation hose on my GS was pinched
and absolutely blocked when the bike was new. Thanks for the hint!
haakon#626 (Norway,12-1999- F650GS)
- I still think that motorcycle batteries are sort of delicate and can be
damaged by a sharp hit that might break an internal connection that was
not welded properly at the factory. Goldwing-sized Yuasa batteries are
infamous for this kind sudden of failure. Richard #230
- Most modern street motorcycles will not run without the battery. The
battery is like a dam placed over a river. During the winter it keeps the
lowlands from flooding and during the summer it provides water that would
not be there otherwise. Think of low rpms as the summer and high rpms as
the winter. Most bikes will run at high rpm without the battery, but will
stall immediately when the revs drop. Keeping the engine running without a
battery, or with a dead battery installed, will likely burn up the VR
quickly, melt the alternator wiring and burn out more than one electrical
component due to high voltage - if run for very long without a working
battery. Richard #230
- Hadn't checked the fluid level in my classic since mid winter (original
Yuasa '00), so after this morning's ride I pulled the side cover to take a
peek. There were no signs of battery problems and other of life's problems
had me somewhat neglectful for the last few months. I consider myself
lucky after finding the front cell dry (bone) and the other five under
half full. I topped each to max and plugged in the BT. Within 10 minutes
the green light started flashing indicting 80% charge and it's been
flashing now for about seven hours. Hopefully, by morning it will be
steady green indicting full charge. Sometimes we get away with being
un-attending. The only thing I can think of is that the daily use of the
Bat. Tender kept it from crapping out. I thought they die without fluid.
Guess not always. I don't get it. With a dry cell and the others very low,
it was still STRONG. I guess they are making better products these days
with newer technology and serious competition that was not there 20 years
ago. Yup! Steady green. Amazing. Thanks Deltran. I'd like to see the day
when a maintainer comes with the bike (built in chip or something) and
those lights are in the dash. I have a hydrometer and WILL check it. I'm
really PO'd at myself for not checking it in four months. How stupid! In
low light I just put a flashlight to the side of the battery. Helps a lot
to read the fluid level. Art884 No. NJ, LT - SE - GSA
- I had that same thing happen a couple of times. I actually checked once
and all the cells were less than half full. I'm amazed that the thing
lasted as long as it did. I just replaced it this year. ('99-'03) For
those reasons I decided to go with the original Yuasa, just wish time and
necessity hadn't force me to pay for the BMW box at the dealer. Same here, in fact
the first time I discovered it that low was the day following riding w/DHP
and Jimmy Lewis when, because of the instruction nature of it, I had
stopped and restarted my bike at least 50 times. Never missed a beat!
David#476, '99 F650, R60/5, K75RTA, Las Vegas.
- You can't depend upon the Battery Tender's green light. The battery could
still be on its way out. You can have a good voltage reading, but little
capacity in the battery. Use a hydrometer on your fully charged battery.
If you see any readings that show a difference between the specific
gravity of the cells (such as all cells fully charged, but one only half
charged), start thinking about investing in a new battery. The old one is
on its way out and will expire within the next few months. Play it safe
and replace it when you get a chance. It is very likely that the cell that
was dry is damaged and will place a strain on the rest of the battery
cells and your charging system. Richard #230
- Funny I had the same thing happen this past week. My F650 was barely
turning over with the electric start, was considering buying a new battery
but instead invested in a bottle of distilled water and learned how to
take my battery out. A little water went a long way, it now cranks with a
second or two every time I start. I just hope it lasts... can't believe I
was looking into buying a $70 battery when all I needed was a little
water. Thank you FAQ's! Mike-GeekSupreme
- A recent discussion on batteries that appeared on the IBMWR List indicaters that premature failure of sealed AGM and Gel Cell batteries is not all that unusual. According to one of the List's frequent tecchie contributors Tom Cutter, AGM and Gel Cell batteries are designed for maintaining a moderate charge and begin to get stressed when higher starting voltages are required. From what I recall of the discussion, the connections between the battery cells can often burn like a fusible link when higher (starting) voltages are required.
According to Tom, while touring the Panasonic factory that was making sealed batteries, he learned that there are no quality control standards for the fabrication of the metal linkage between cells. This would seem to indicate that the longevity of AGM and Gel Cell batteries is a hit and miss proposition, with some dying early in their life and others lasting for a number of years. As an example, the stock BMW AGM battery in my '04 R1150 GS died at just over 2 years and 60K miles of use. I have recently installed a Westco AGM battery in my '97 F650. I am hoping that by changing to a new battery every 2 years, I will at least reduce the possibility of ending up with a dead battery at night, in the rain in Bullet Hole, Wyoming BeemerGary #1605
What on earth is EDTA?
Pb is the symbol for lead on the periodic table. Your battery gets a
certain amount of lead in its plates when it is new. Some of that
dissolves into solution when you pour in the acid. Some of it turns into
lead sulphate when things are not working quite right. (Adding EDTA
prevents that.) If you allow the extra liquid to boil off the lead stays
in the battery. The liquid does not actually boil in that it never gets
that hot. It DOES electrolyze into hydrogen and oxygen and the vapours go
away. Anyway, if the lead stays in the battery, you haven't lost anything
when the level draws down except for water, which you happily add back in
(in the form of DISTILLED water). Removing electrolyte is not a good idea.
There is Pb (lead) dissolved in the electrolyte and you'll diminish the
capacity of your battery by removing it. The battery on the F boils off
electrolyte fast enough that it won't be overfilled for long.
The EDTA somehow keeps lead sulfate from forming (or keeps it soluble).
The lead sulfate is formed from the lead + the sulfuric acid in the
battery. Lead sulfate is insoluble in the electrolyte, and sinks to the
bottom of the cell when it flakes off. When the pile of lead sulfate gets
big enough, it bridges the gap between the plates, and you get a dead
cell. If it doesn't flake off, it reduces the effective surface area of
the cell, slowly reducing its capacity.
EDTA works by binding divalent cations (lead in this case) therefore
inhibiting the formation of lead compounds. For already formed lead
sulphate...the reverse reaction is probably enhanced (not sure).
Tetrasodium-EDTA is relatively water soluble compared to disodium EDTA. If
you dissolve it in water first you can then add it to battery electrolyte
which is approx 4M sulfuric acid. I don't know how long it stays in
solution. If you dump the powder straight into the battery very little
will go into solution. If the 'powder dumping' approach yields results it
suggests that very little is actually needed. As per Google, In general,
use one tablespoon per cell in a golf cart battery such as a Trojan T-105.
There are approx. 40 tablespoons in one pound. George#384
http://www.deathstar.org/~flash/edta.html for a heap more information
EDTA - a Critical Voice (long) - from OyvindSn, Norway
I posted a question regarding EDTA as a battery preserving agent on a
boat-related newsgroup some time ago. A gentleman by the name of Frank
(For the entire discussion, go to EDTA - a Battery Preserving Agent?
I spent over 20 years in the battery industry, starting at the Exide
battery research center in Yardley Pennsylvania. Battery additives and
rejuvenators have been a hot item as long as batteries have been in
Sulfation is the most often mentioned failure mode that these additives
are supposed to correct. The problem is that the formation of lead sulfate
is the normal manner in which a battery delivers its energy. The active
materials in a charged battery are PbO2 (lead dioxide), with a valence of
+4, in the positive plate and a porous form of lead called sponge lead,
with a valence of 0, in the negative. On discharge the active material of
both plates becomes lead sulfate (PbSO4) with a valence of +2. On charging
the lead sulfate is converted back into the respective active material.
Both the PbO2 and Pb on the plates are conductive, the lead sulfate
discharge product is essentially non-conductive. As long as the crystals
of lead sulfate formed during discharge are very small, their proximity to
conductive portions of the plate permits them to be converted back to
active forms. Destructive sulfation occurs when the PbSO4 crystals become
larger and more difficult or impossible to be converted back into active
This occurs through a phenomenon called Ostwald Ripening. OR causes
crystals to become larger over time. The best way you can see this would
be to take a small jar of water and add sugar till no more will dissolve
and then add another spoonful or two. At first when you stir it the powder
in the bottom will swirl around easily. By the end of the day a crust will
form on top of the sugar so the powder will no longer swirl. In a few days
you will see crystals growing. Over time they may get to be a quarter inch
or more in size. In your battery the PbSO4 crystals will be quite a bit
smaller, but if you were to take apart a sulfated battery and dry the
plates you would see them sparkle as light bounced of the crystal
This sulfation is essentially irreversible. Battery manufacturers have
tried to combat it since the beginning of the last century. Besides tying
up active material the, sulfation also consumes the sulfuric acid
electrolyte. As the battery degrades the acid concentration drops and the
internal resistance of the battery goes up. This rise in internal
resistance further limits the power output needed to start your vehicle.
Most battery additives act to decrease the internal resistance which means
that, for a limited time, you can more efficiently access the remaining
power in the battery. Depending on the application (initial condition of
the battery, power requirements, temperature, etc.) you may get anywhere
from a week to several months of additional use out of your weakened
One of my first jobs when I joined Exide in 1969, was to analyze a new
battery additive called POW'R. When I complete the analysis I discussed
the results with one of the Old Timers who had been designing batteries
for over 40 years. The major ingredient was magnesium sulfate (MgSO4)
otherwise known as Epsom salt. He said Epsom salt was the old standby for
additive charlatans. It gave a quick reduction in internal resistance but
could do nothing to renew an ailing battery. There was enough cobalt (Co)
in the additive to give it a blue color. My friend said that cobalt would
reduce the voltage required to charge the battery which might help if the
car's charging system was weak. The downside was cobalt also causes the
battery to self-discharge more rapidly and accelerates corrosion of the
positive grid. There was nothing else of any value (?) in the stuff. At
the time it sold for $7 a bottle (maybe $30 adjusted for today's
At that time I told him that a lot of people thought it was possible to
make a really long life battery but that the battery companies didn't do
it because they wanted to keep sales up. He said there were 5 major
companies. The company that could find a way to make a demonstrably better
battery (for a price) could blow the others out of the market. If you
could dominate the market why would you sit on the idea? He said that he
could make me a 15-year car battery The only problem was it would cost
five times as much as current batteries and weight 250 pounds.
As to EDTA in batteries, it will increase conductivity of the electrolyte,
which may give you a brief reprieve as noted above. In addition, it may
increase battery capacity for a time. As a salt of an organic acid EDTA
will again become an organic acid when placed in the battery. Organic
acids readily attack the metallic lead of the positive grid structure. A
small amount of organic acid can consume a large amount of lead grid
because the reaction recycles the acid back to its original form to
continue the attack. The corroded grid material will be able to withstand
a few charge-discharge cycles but will fail fairly quickly. Over time
(dependent on depth of discharge, frequency of use and temperature) the
positive grid will corrode through and the battery will fail.
In other words, a battery that is close to failure might be brought back
for a limited amount of time. That will give the battery a chance to
finally fail just when you need it most! If the battery is known to be
weak, it is best to replace it as soon as possible rather than hoping you
won't be in the middle of a serious situation when it does fail. The only
valid use I can see for battery additives would be to have some Epsom salt
in your tool kit so that you can try to get one last start out of a bad
battery when caught unaware.
Epsom Salt. The FAQ (battery section) mentions that it is a good idea to
bring in a long trip some Epsom salt with you in case the battery dies. It
seems that adding the salt to the electrolyte can give you some extra life
in case of an emergency. Since the salt is cheap, has multiple uses and
can be found in any CVS/Walgreens/Osco, I was thinking to add a small
ziplock with some salt to my spares. Any experience with that ? Which
quantity should I add to each cell ? What's the chance I'll end up in jail
if a cop finds me with a small ziplock full of white crystals?. My idea is
not to rely on the magic properties of the salts, BUT a small ziplock
takes no space in the tool bag. My assumption is that IF I am stuck in the
middle of nowhere and the couple of grams of salt I have in my tool bag
can give me an extra kick to get to the next gas station. Why I shouldn't
try using them ? Thanks Giovanni '97 F650, Waltham, MA.
I doubt very much that this works. If the battery goes bad you want
a NEW working battery on a trip so you don't get stuck in the middle of no
where. Since you should be able to get s jump start if your battery is
toast and that should get you to a new battery source I see no reason to
add Epsom salt or carry same...sounds like a good way to have an
explosion! But it would be interesting as a experiment at home with a
known dead battery. F650GS Dakar, Camden, New Jersey.
Let's see if a PhD in chemistry can help...not likely, but I'll
take a stab at it. BTW, I've never heard of this fix it. The acid used in wet
cell batteries is sulfuric (H2SO4), while Epsom's salts is magnesium
sulfate (MgSO4)..sorry, don't know how to put in subscripts. Anyway, if
the battery was dry, and not just low on water (and therefore much more
concentrated sulfuric acid), one could add water and Epsom's to get the
active electrolyte, sulfate, nearly correct (the Mg is not good in this
respect) and then if you could push start, in principle you could get the
battery to charge. Don't know how well it would work in the face of lots
of Mg, but I guess it's possible. However, if the battery was merely low
on "water", I'd never add the Epsom's, but rather just add deionised water
(to prevent the addition of undesirable ions like sodium, magnesium, etc).
OK, there's my attempt. I can draw a mess of equations, but too difficult
on this mode of communication. Cheers, Greg '02 F650GSA, Norfolk,
|Note: In some states / countries, the adding of
epsom salt (or for that matter, other additives) to batteries may be
illegal. Ensure you follow the manufacturers instructions and all
appropriate laws. But this was common sense right?|
External Battery Links
Order will grow out of confusion... Winter