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 this FAQ.
Last Updated: 13 June 2007, by Winter #1935

• Introduction
• Battery List / Battery Selection Questions
  • Unsealed Batteries
  • Sealed Batteries
  • Battery Selection Questions:
    • Terminal Semantics - Which side is RIGHT and Which is LEFT?
    • Are the reversed terminals on some Batteries hard to rectify?
    • Is the battery ground on the positive or negative side?
    • Is putting a SEALED Battery in Sideways (Stand it on End) OK?
    • What CRITERIA should I be looking for in a battery for the F?
    • What is AGM and how is that different from Maintenance Free?
    • Is BMW installing AGM batteries in newer (2004 onwards) F650s?
    • BatteryWeb Misc
    • What about Walmart batteries?
    • How reliable are AGM batteries?
    • Has anyone heard of or used BigCrank Batteries?
• Modifications and Installation
  • Battery Removal - Disconnecting and Reconnecting
  • Fitting a Westco in a Classic
  • GS/Dakar Tray Modifications
  • Any problems with the oil reservoir melting the side of the battery?
  • Hawker (SBS8 and PC310) Sealed Battery
  • Odessey PC310
  • Has anyone had luck installing the SBS 8 in a 2002 GS
  • Does the adapter just fill the extra space, or is it also needed to make the electrical connections work?
  • Exide / Yuasa Sealed Battery
  • GS Charging Access
  • GS Battery Drain Tube
  • Hooking Tender to Alternator or Battery
  • Alterative CS Batteries
• 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
  • EDTA
  • External Battery Links
  • Battery Guages? See the Aftermarket Voltmeter FAQ

For other related FAQs:

• Classic (and some GS) Hard Starting Poor Running FAQ
• GS specific Hard Starting / Poor Running FAQ
• Electrical Misc FAQ

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 alternator.

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).

Battery Selection Questions

Here is a tip: A good place to compare battery designations, sizes and configurations is in the JC Whitney catalog (http://www.jcwhitney.com). Their 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

• 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

• 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.

The negative terminal of the battery in an F650 is connected to the chassis and therefore called "ground." Flash 412 (CO)

• 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.

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 substitutes.
• 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.

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

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 #230.

• No, this is not true for the new F650s. The 2003 and 2004/05 models come with the same unsealed Yuasa battery.

• 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. John
• 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? Thanks again!
  
  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.

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, #1244

• 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.

• 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 section below.

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.

Supertech, Brian#179, Andy #982,

• Always, Yes Always disconnect the negative terminal first and ALWAYS, when reconnecting, connect the positive first. ANY Battery, Bike or Car.
• 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 negative terminal.
• 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 Panels?
Sure. See the GS Fairing FAQ.

• 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 http://www.batteryweb.com/motorcyclepanasonic.cfm .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 #631
• 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 #436
• 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. Alan #442
• 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

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 F650GS

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 view):

1. Remove seat. Remove the center tank panel, and the right side panel. Remove the battery (negative terminal first).
2. 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 step).
3. Using a torx driver, remove the screw from the plastic relay cover. Remove relay cover.
4. Using a socket, remove the two nuts that hold the metal bracket near the plastic relay cover.
5. 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).
6. 
   

   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 dmemt #1464):
   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 dmemt #1464):

   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)

7. 

   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).

8. 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.
9. 

   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.

10. 

    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.

11. 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:

1. The nuts on the bottom of the bracket are epoxied on. I "broke" them loose with an 11mm box wrench and a hammer.
2. 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.
3. 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.
4. 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 problems.

Note: In TWO instances the YTX14AHL-BS has been installed with minimal changes:

• 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 position. McGuireV10
• 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 nothing! Ed@Ford

Method 4 (by billmallin, #1629)

1. 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.
2. 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).

3. 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).
4. 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 fit.

Feedback

• 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

(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

• 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, http://www.touratech.de/english/products/enter.html (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. Hawker 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. Mason #631
• 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 #926 Calif.
• 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. http://www.touratech-usa.com/shop/BMW_F650GS.lasso, http://www.hepi.com/default.htm. 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). andy112652 #1481

• 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

• 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:
  1. Pull the right side faux tank panel off
  2. 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.
  3. 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 so far.
  4. 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).
  5. 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.
  6. 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 #1441

• 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 #1618.

• 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, Glide OR
• 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

• 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 well).
• 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 (CO)
• 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 F650GSA.
• 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 CA
• 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

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 there?

• 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 #951
• 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. Todd #389
• 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, CA #782
• This picture shows the battery tray, and the drain tube in its "normal" position. Winter #1935

• "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 #1549
• 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 differences).
  
  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 that.
  
  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

• 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 here.

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 Regulator.

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?

• There's some really good detailed discussion in "Everything you never wanted to know about batteries."
• Here's an article on MC batteries worth reading: http://www.mcnews.com/articles/battery.htm
• A FAQ on MC battery care here: http://www.exideworld.com/faq/trans/faq_motorcycle.html, http://www.bmwmotorrad.co.za/workshop/battery1.html. (Ian #1062)
• Great Information. http://www.gsbattery.com/MB/index.html

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) '01GS
• 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 that?

• 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, Oz.

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 #1629
• 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. Trevor #999

How do I remove the battery from my CS?

1. 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 flasher.
2. 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 battery in.
3. 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!
4. 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. Liv, Norway

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 use?

• 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 amps.

How long should it normally take to charge the battery on a Battery Tender?

• 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 anywhere?

• For those interested in burning solder, here is a link to a 3 amp battery charger/float charger circuit and instructions: http://www.uoguelph.ca/~antoon/circ/lader.htm (Northwet). And for those electronically-minded riders, look at this home-brew charge minder: http://www.electronic-circuits-diagrams.com/carsimages/carsckt1.shtml (Ian #1062)

My Battery Water is always Low. I suspect the VR is overcharging the System. Is there a solution?

• Yes there is. See first the the VR FAQ, then have a look at the Flaying the VR FAQ.

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 VR FAQ.

Do you have any more information on the F's Charging system?

• See the Electrical Misc FAQs - DC Electrical Basics.

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 amps.

Is it okay to charge the battery on a GS/Dakar/CS bike (with an FI computer)?

• 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) Fizz

• 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 terminals).

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: http://www.yuasabatteries.com/motor_battery.asp 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. Marty #436
• 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. DaveJ#888
• 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 Questions.
  
  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:
  1. 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.
  2. BMW dealer: "The Tender brand will not work on a sealed battery." WRONG, wrong, wrong.
  3. 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 #1244.
• 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 (CO)
• I use a Battery Tender Plus. So far, so good, no problems. DaveJ#888
• 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 Dakar
• Battery Charger Optimate III - On board http://www.accumate.co.uk/it010003.html. stream2003
• 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, chiefkeefe
• 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 DR350. EssexDakar
• 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 this: www.yuasabatteries.com/faqs.asp. Richard #230
• 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 use:
  
  "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. Hunkystuff

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 battery?

• 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 Airfilter Cover with two big red wires coming out of it) symptomatic of a Flat Battery?

• 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 FAQ.

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 #1546
• First, check the battery. Second, toss the battery. Third, replace it with a new one. Or just skip to step three. SScratch #1082
• 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." Marty #436
• See also the Hard Starting and Poor Running FAQ.

My ABS light came on while riding and stayed on. Now the bike won't start!

• 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