Eating Celery (And batteries)

acbanks · Posted: October 25, 2009, 3:41 pm Post subject: Eating Celery (And batteries)

I've been working with this charging system all year. I've chopped the wiring harness up completely in search of tenths of volts. I now have a switch beside the battery and fresh hot wires everywhere. I've got it wired so that I can start it with just the ignition on(no headlights or lights), then add the charging system later.(ignition coil draws 2.5A, with the alternator rotor it draws 5A.) Running a new radio shack rectifier and VR292 regulator.

At idle the best it can do is 12.2V with ONLY the ignition coil and rotor pulling current. At 3000rpm it manages 13.8V, (with the old mechanical regulator it would go to 14.2V). Turn the headlight on and it's a steady ride down to 0V.

The only wire I haven't yet replaced is the green wire to the rotor, but adding a straight 12V jumper to the alternator only helps slightly(12.3V idle). New brushes, cleaned rotor contacts with 800 grit sandpaper.

At this point I figure my only option is to replace everything. Or switch to a permanent magnet setup, but even that would cost more than $200.

I live in the city, so if it can't at least hold 12V at the stoplights until I can find open road, the bike is junk to me. Any suggestions appreciated.

pamcopete

acbanks,

Well, bypassing the regulator eliminates that, you changed the brushes, so only a couple of things left:

1. Did you measure the rotor resistance? (5 Ohms)
2. If you hadn't told me that you replaced the rectifier, I would have guessed it's a rectifier problem, so perhaps a review of the Radio Shack installation might produce an answer. Generally if there is one diode in the rectifier that is shorted or not connected properly, you will get the re sults that you have.
3. What year/model is your bike.

acbanks

Rotor resistance is 5.5ohms. I just checked the rectifier diodes, working correctly. I just pulled the stator and it's wiring harness. I get about 5 ohms between each of the white stator wires. I'll clean off the corrosion there and on the plugs and see if that helps. They're the only wires I haven't replaced, since they have that protective plastic jacket on them.

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

I had a similar problem, it was a bad batery. What type of batery do you have?

acbanks

Success. More or less.

I pulled the stator off, replaced the wires going to it, and grinded clean every terminal related to it left in the wiring harness(this time with my dremel and a small bit.)

Now at 1000rpm(slowest possible idle) it will run the ignition and alternator and hold the battery at a steady 12.2V. At 1000rpm it loses voltage trying to power the lights as well.

At 1300rpm or so it will run the headlight and taillight as well, again at a steady 12.2 or so. Turn off the lights and it shoots up to 13V or more. The max I've seen is 13.8V at 3000rpm.

I think I'm going to call this good and try to keep my idle a bit high at stoplights.

Thanks for the suggestions, guys. I was really banging my head against the wall on this one.

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