charging system?

[ckp543]

I have an 83 r100 rs When I turn the key on it stops at 10 volts for a half second then goes a little before 12? is it powering up? when at Idle the volt meter will begin to gradualy drop but as soon as the rpm gets around 1200 it goes back up? I was thinkin maybe battery starting to go bad?

[20774]

Don't trust the fairing voltmeter. Put a voltmeter you can trust across the battery terminals and repeat. Then let us know what you find. You might just have corrosion on your grounds, to the fairing voltmeter and/or battery.

[toooldtocare]

On my old R90S the volt meter never read more than 12 volts at any RPM. When idling it would stay around 10 volts. I cleaned every connector I could find, replaced some of the wiring, and even the fuses. A digital volt meter at the battery showed that it was about 12.5 at idle, and 14 at 3,000. I just gave up trying to fix it.

Even my current R100RS (78) the volt meter never shows more than 13 volts, but again a volt meter on the battery shows that this is wrong. When I use the turn signals the volt meter swings from 13 volts to 10 volts with each click of the turn signal relay. It reminds me to cancel the turn signals better than the light.

[ckp543]

I checked with a volt meter I'm charging fine but my batery was low its a couple years old so I put a charge on it the volt meter behaved a little better put about 60 miles on it today so I'll chalk up the volt meter as a pretty accesory that just gives a general idea!

[jforgo]

The voltmeters may not be accurate on an absolute basis. But their usefulness is with relativities, as with what happens when you increase revs, versus at idle. After all, all of mine go wildly down then up when using turn signals; I reallly doubt those two little lamps take it down to 4-6 volts, as one of my RT's shows. The voltmeter functionality is for trouble warning, not diagnostic tool.

[Bill Burke]

The voltmeters are handy to test your headlamp and other bulbs. If you turn your lights on and off or flash your brights, and your meter doesn't dip down, you know you have a bulb or switch issue.