Originally Posted by JRWooden
I have just posted a poll over on F800Riders forum for the F800S / F800ST riders to use:
As best I can tell, those bikes share the same original stator & flywheel design, so we'll see if we learn anything from their experiences ... since that design point has been around since 2006 (I think?)
It was of no good use when the stator failed and battery started discharging.
I think, the led thing threshold is too low for any good info. by the time you get to the less than 12volt yellow level, your're screwed anyway..
What I think is needed is a proper voltmeter, so you can observe the "high revs charging voltage, with normal running load". Since the problem is no charging, that's what we need to be looking for. An ammeter would be the classic thing, a digital voltmeter can be installed easily.
What i did observe, while i still had enough juice to start and drive (for maybe 10 more minutes)was that the odometer resets to normal from trip A. I noticed this because i always drive with trip A displayed for gas mileage guesses. And then when you stop for gas, restart, and can't reset the trip A cause it's changed to normal, DON'T LEAVE THE GAS STATION !!!!!!! YOU HAVE A PROBLEM.
Also, and this wasn't nearly as clear as to there being a problem, the various other displays on the instruments began to boot (when key turned on) oddly. Some of the idiot lites would act differently than normal, flash oddly, meter needles not sweeping.
My performance running on battery only, seemed much better than an hour. That's a guess, without some measure of charging ability. My first failure was on a shady street on Boise City OK. Really low Lithium battery, 7.5 volts. I bought a new AGM 14BS, a half block away, put in the acid, stuck it in the bike and rode away. I went several hours, spent the night near Guymon OK, rode the next day, stayed near Ponca City OK, rode the next morning to Coffeville KS, the battery died again. I walked a half mile and bought another 14BS (walmart carries these), put it in and rode to the Sedalia rally site. There's no knowing if any of those extra batteries were getting charged by the bike, but they definately did not get a "full overnight" charge before use, i just put in the acid and drove away.