Charging System Flow chart

Redmachine76

I have a 1998 Ultra that now has an intermmitent charging problem. The stator and regulator seem to check out as OK. If I let the bike sit for a few days and then start it, all seems to be Ok until I run the rpm up over 3000. At that point, the red warning light comes on indication some kind of system problem, the charge rate drops off to zero, and I get no charging until I let it sit again. At this point the stator is still putting out the suggested AC voltage, the regulator seems to be putting out 15 volts, but not charging. Are there other parts to check?

Hoople

What would that voltage be and how did you check it.?

You said the regulator seems to be putting out 15 volts.
At what RPM did you measure it.

Jack Klarich

Is 15 volts high and what is the state of the battery, if its low and bad like a car charging system it could never catch up and cause damage JMO

Redmachine76

I charged up the battery overnight so its putting out 12.5. The fact that the charging system worked until I revved it up and then I got the computer system light concerns me. Whern I turn on the key I dont get any blinking light codes, seems to check itself out and be fine.The Computer board is new, maybe 10,000 on it. When I revved it up the charge went up a little, but then shut down. Is there any computer involvement in this system?

I measured it at 2000. Next time Ill have a meter on it and watch what happens at 3000. I have run it up without the regulator attached and I get increased AC Voltage from the stator, I saw it rise to 50 or 60 volts AC

Hoople

Have you actually taken a voltmeter and checked the voltage across the battery while at idle, 1500 RPM, & at 3000 RPM. If so, what readings did you read. If not, I would say that would be where I started testing.

To check the stator without a load gets involved. Don't put a lot of value on those readings.
That stator is 3 phase and you would have to check it across wire 1 & 2, 2 & 3 and 1&3. Just go with checking the output of the regulator for now using a DC voltmeter.

Redmachine76

Yes, did that...It was reading 14.5 until I revved it up, jumped a little then at 3000rpm it shut down the charging, then it was reading 12.3 or so. Im going to get it going again after it sits a while, try to get it charging and have a buddy change the rpm while I watch the charge rate. It would seem to me that either the new regulator is also bad or there is some breaker or some other device that is sensing a problem or high voltage. Im stumped

This is a 1340 Evo and only has 2 leads...well thats all I can see...

Hoople

OK.. Then it is not 3 phase. You still can't put too much weight on those AC readings.

It sure looks like it is pointing to the regulator being bad. Like Jack said earlier, 15 volts seems very high to me also. The regulator may be shutting down to protect the ECM from excessive high voltage.
I would say 14.5 should be the Max I would like to see coming out of the regulator.

Makes sense there would be something in place to protect the ECM from dangerous voltage runaway.

I wish I could see the schematic of your bike. I would like to know if you have fixed Maxi fuses or resettable CB's in the charging circuit. Before I replaced any parts I would check the prints to see exactly where the B+ regulator output wire goes to. With that info you will know where/why the shutdown is taking place.

Redmachine76

Ill check the schematic and see where it goes. Thanks!! I may be back!