Charging question

I have a 1991 R100RT w/ 34k miles on it. when riding the volt meter will stop working. I've installed another volt meter, but it loses power also. If I blow the horn or flash the lights everything starts working normal again. Where do I need to start looking to cure this problem? Also in the near future I would like to upgrade the charging system. What is the best choice for this upgrade? Thanks for any and all info.

My guess would be that the issue has to do with the grounds. I'm assuming this is the stock installed voltmeter which has a wire that runs through a connector block and then goes to the #58 fuse on the circuit. The grounds appear to be common with the clock and the LH indicator. I'd try and trace the wiring as far back as you can go. Alternatively, you could wire the voltmeter directly to the battery. Where it is plugged in now probably reads 0.5v low if not a little lower. Running the power lead all the way back to the +terminal on the battery tells exactly what is happening at the battery.

There's been some discussion about charging systems in the past. You can also read about a comparison here:

http://bmwmotorcycletech.info/AftrMrktAlt.htm

Be sure and check the Resources and Links thread in the Charing and Electrics section for more information.

Thanks, the enduralast looks like the one for me. I'm going to keep looking for a bad ground...

20774 said:

Alternatively, you could wire the voltmeter directly to the battery.

Click to expand...

Ideally that is how they should be wired. Depending on the current draw, most will have to be switched off with a switch. Mine is on all the time...it only draws 2 mA.

20774 said:

Where it is plugged in now probably reads 0.5v low if not a little lower.

Click to expand...

If it is the same analog meter I had on one of my previous BMWs, it can be adjusted to read correctly for the location it is tapped into.