The Voltmeter FAQ
compiled & edited by Kristian #562
Please read the Disclaimer before attempting any work in this FAQ.

There are so many ideas, we had to make a Separate FAQ.

Hand-held Voltmeter Usage


To check the Rectifier, for best results, make sure the bike is good and hot. Don't check it cold. Start the bike, rev it up to about 3-4K rpm and check the voltage at which the battery is being charged. You will need a Voltmeter (VOM), with one probe placed on each of the battery terminals. The Photo shows a setting at a minimum sensitivity at 20V which is a bit too high for the range you want to measure. The next one down is 2000 mV or 2V which is the one to choose. If you're not sure, START high, then go down, so you don't blow the Voltmeter. Refer the Voltage Rectifier FAQ.


Make sure you know the accuracy of your VOM when you buy it. That doesn't mean you have to get an expensive one! As an example some meters in the 25$ range have +-2% +- 2 digits accuracy, meaning that a 15.0 Volt reading could be anything from 14.5V to 15.5V. Others in the same price range may have +-0.5% and plus minus one digit accuracy which would give you a actual voltage of about 14.8V to 15.2V. Another factor is that only some meters from 100$ and up show "True RMS", others assume that DC is DC and all AC is perfect sine wave. RakaD.

Aftermarket Voltmeter in the Clock Space on the Classic

Werner #547

If you can, or want to, live without your timepiece (clock) and opt for a Voltmeter (VM) this is what you do:

You buy a HASTINGS TA 1109 Volt Meter, because this model fits exactly into the cup holding your clock (650 Classic; I don't know about the GS - NOTE: This is your Temp Gauge location in Pre-97 Classic F's. Advise you keep the Temp Gauge and put a VM Elsewhere - Ed.).

Removal of clock:

  1. Disconnect ground strap of battery.

  2. Unscrew bolts holding fairing to tank on both sides, and lower fairing on left only. Unscrew the two Philips Head screws holding fairing to console. Do not touch flasher wires, but support sagging fairing with a wire on handlebars to take strain of flasher wire.

  3. Unscrew nut holding clock with 6mm wrench. Lift out clock partly, to see wiring set-up. Pull apart four-prong plug and single wire plug. Lift out clock with wiring harness.

  4. Take off O-ring from clock, and put it on VM. It will fit perfectly.

  5. Pull off bushing and rubber grommet from mounting hole of clock. Keep for future use, if any.

Installation of VM:

  1. Make a dry run, and see where everything will end up.

  2. You will note that the two threaded metal studs of the VM are a bit short to hold the bracket supplied by the manufacturer. Find a piece of non-conductive circuit board, and, using the metal bracket for a template, drill the two holes for the studs. Make another dry run.

  3. Before installation you have to do the wiring. You have three choices: (a) You can pull a separate wire from the VM directly to the battery. But then you must install a switch somewhere to turn it on or off manually. (b) You can use the red and white wire of the clock as a power source, but again you have to install a separate switch. (c) I chose to use the grey and yellow wire of the clock. This is the wire that powers the light in the clock. The advantage is that it is controlled by the ignition switch. The disadvantage is that since it goes through so many gadgets, there is a voltage drop of about 1+ volts.

  4. Cutting the wires: You cannot get into the clock. I tried, but broke it. So cut the wires about 1" before they enter the housing, in case you want to reverse the operation later on, then you just have to solder the wires together. I used the brown wire, which goes to minus pole of VM, grey and yellow goes to plus pole. Ignore black, which was fast forward for clock. I soldered crescent lugs on ends of wires, then connected the wires to the threaded studs of the VM, to which I also connected the enclosed light of the VM. Test the assembled unit with a multimeter.

  5. Feed wires into cup, followed by VM. Check on the bottom where wires emerge, adjust. Push down, and slip non-conducting bracket over studs, and tighten the two 8mm nuts (supplied) gently.

  6. Connect the modified four-prong plug (only two poles are active) to its female part, and the lone wire from the fast forward switch, just to get it out of the way. Test installed unit with multimeter.

  7. Connect battery, turn ignition key, and read about 11.5 Volts on the VM (there is a heavy load on the circuit with all the lights on).

  8. Start motor and watch your work of art in action. For those of you who prefer clocks, eat your hearts out!!!)

Hodger VM Installation on a GS
by Seacuke #1214

Above is the schematic for a simple voltmeter that could be used to monitor the voltage on an F650. I borrowed heavily from Forrest Cook, whose excellent circuit can be found here. In fact, the only thing I really changed from his circuit is to remove most of the bells and whistles from it.

The cost of all the parts I used to create this circuit follow:

LM3914 IC $2.25
3 Yellow LEDs (5mm) 3 x $0.19
3 Red LEDs (5mm) 3 x $0.19
4 Green LEDs (5mm) 4 x $0.19
Potentiometer, 200 Ohm $1.15
Potentiometer, 5K Ohm 2 x $.59
Resistor 4.7k $.10
Resistor 1.2k $.10
IC Socket, 18 pin $1.49
1" x 1" & 4" x .5" PC Board ~ $1.00
Total Cost $9.17

The output of this voltmeter is a bar of LEDs, each LED representing 1/2 a volt, with the entire scale ranging from 10.5 volts to 15.0 volts.

Here's a picture of the whole unit, with a pen in the foreground to show the size.

The Adjustments

Alternative Lighting

Installing the Hodger Volt Meter


Datel Volt Meter on a CS
by RideFast


Parts List      
Part Price   Purchased From
Datel Volt Meter [DMS-20PC-0-DCM]
Quick Switch Wire Crimps [5 pack] $2.39    

Total Cost:



Installation Notes:


Windshield Removed Bracket Removed Cut Out Make Sure it Fits Running the Wires Wires Crimped


Riderwearhouse Voltmeter

Datel Voltmeter
by Abe #963.

Custom Dynamics Voltmeter Installation

by Richard #230

Kuryakyn Voltmeter Installation
by Richard #230

I finally received my Daring Kuryakyn Products ( "Universal LED Battery Gauge # 4219 (part number 604219)" voltmeter last night. The total cost to my door was $34.30. The voltmeter is housed in a small, very light chrome plastic case. It is 45 mm long, 25 mm tall and 12 mm thick. It has two wires about 12 inches long that have no connectors attached. It has 9 LEDs with an automatic "day/night" brightness control. The gauge is calibrated in 1/2 volt increments from 8-16 volts. Green LEDs for 12.5 to 14.5 volts, yellow LEDs for voltage above or below those values and extreme high or low values result in flashing red lights.

Frankly, the device doesn't look too weather-tight to me, as it has a big hole in the back where the wires come out. The instructions claim a 30 minute installation time, so it should take me 60 minutes. My plan is to hook it up to my new Ninjatte this weekend, as it has a nearby accessory power access just under the front fairing. I'll report back next week, if I haven't burned down my garage (I'm not too good with electrical stuff).

On the Kuryakyn meter all of the lights light up when it first comes on, then all of the lights to the left of the highest voltage reading light up. The top of the case is curved and there are imprints under the LEDs that mark their voltage. It is quite bright and gets even brighter in the sun. What I thought was a hole in the back of the meter (under pool lighting) was really sealed with a clear sealant. My only problem was that the spare accessory connectors that I hooked the meter to were not switched by the ignition circuit and resulted in the meter being on all of the time (it made a great garage night-light). I then realized that a few days of this would drain my battery and installed an in-line on-off switch to turn it off. Why didn't I just find a wire that was switched by the ignition? Because I had already cut the wires too short and couldn't reach the headlight wires. Now you know why I don't give electrical advice. I have a couple of comments about the Kuryakyn voltmeter after having used it for a day:

The voltmeter acts like a battery tester when you first start the engine. If the battery was bad, the voltage would drop below 10 volts, when the starter is engaged and the red LEDs would come on and you would know that it was time to look for a new battery. When I first turn the ignition on the meter reads 12 volts. When I hit the starter button, the voltage drops to about 11 volts (yellow LEDs), under the load of the starter. Then when the engine starts, it rises to 14 volts (2 green LEDs lit), where it stays until you shut the engine off. Even when the engine is off, the meter reads 14 volts. After a few hours with the meter connected, the voltage falls to 12 volts (keeping in mind that this is only an approximate value - typically a fully charged battery would show 12.6 volts).

I do not recommend that the meter be installed in your line of sight. The LEDs are very bright and can be distracting even in the daytime - to say nothing of what they look like at night. I would prefer the lights to be only half as bright as they are. Other than that minor problem, I recommend the meter. I consider it to be a useful tool to keep you appraised of your bike's electrical system's condition and it should keep you from being stranded by a dead battery or bad voltage regulator/rectifier. My radio station engineer friend tells me that each LED uses about 20 ma, so the 5 lights that are lit when the ignition is off would use 100 ma per hour and would drain the battery of about 1 amp/hour every 10 hours. The bike that I have it hooked up to only has a 6 amp/hour rated battery, so if I left the meter on I would be push starting after about 2 days.



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