Charging System Failed Again

[glider]

OK, it's time to get some answers. If they changed the stator and now the battery , chances IMO are that there was one or the other that wasn't bad to begin with.

And what next are they going to replace if this doesn't cure the problem. I would have a sit down with the owner and get some answers myself.

 

[gs34]

I agree 100%. I would want a lot of answers.
If your battery holds 12.65 volts and starts the bke repeatedly, I would request that the old battery be load tested while I stood there and watched.
I smell a rat in here somewhere....what you are saying doesn't add up.

 

[masterguns]

Re: Charging System Failed Again (CONCLUSION (I hope))

Surprisingly, when I arrived at the dealer to p/u my scoot and all along expecting to pay for a new battery and it's installation, the Service Manager met me at the door with the following explanation. Seems they mis-diagnosed it needing a battery. Rather the rectifier was shot. All I could say is that this made a lot more sense to the battery being bad. However, rather than being billed for a 155.00 battery, I had to pay for a slightly higher rectifier. On the ride home everything appeared to be again acting normal, voltmeter reading 14.2 or so. All you guys were right on and I thank you all for your input. I am once again a happy camper and my baby is back resting in the garage. Now it is suppose to rain all day tomorrow. Bummer.

 

[gs34]

Re: Charging System Failed Again (CONCLUSION (I hope))

Well. Imagine that!
Glad you finally got that resolved. Sometimes it can be a real challenge.

 

[glider]

Glad you got it hooked up again. It was probably the regulator all along. I suggest when changing one to do the regulator and the stator both.

 

[NEWHD74FAN]

Way cool that you got the problem sorted. When troubleshooting, the 11.0V at idle was a dead giveaway that the battery was okay, but reving engine, the voltage rose properly to 14.2V AND was able to start the bike hot several times (just not overnight).

Something was "shunting" the current (think volume of water analogy) and dragging the charging voltage 11V (14.2V is normal) down (think water pressure analogy) sapping the current from the alternator as well as the battery.

If a bad rectifier, it would cause irregular half wave DC pulses (low alternator output) or "leaky" (shorted) shunt regulator (parallel across the battery) would drag voltage down (11V in your case) rather than 14.2V, so 2-10A could flow into a mostly charged good battery, the rest flows through the regulator.

Why do you think that finned heatsink on the regulator is so large? It has to regulate a lot of current if alternator at speed puts out 20VDC, so it has to drop 6V at 30A or 180W (mighty big light bulbs' worth of heat), the rest goes to charging your battery, running your accessories and the headlight, fuel punp etc. Mighty big job for an 8 year old charging system.