Battery charging - Yamaha 30

[Nos4r2]

Did you try it with the multimeter set to DC and if so what were the readings?

[Searider]

Set to DC I got very little - less than a volt.

[Nos4r2]

Sounds like there might be a problem with the charging loop that's in there as well. If you can, take it up to around 1500-1800rpm for a couple of seconds. If it's showing under 12.5 volts AC at that point you've got probably got a problem with the 'lighting coil' under the flywheel.

Do a resistance test down to the casing from the two poles.It should show open circuit or infinite resistance. If you get a reading of under 2k ohms then there's definitely a problem.

[jyasaki]

AC meters read RMS values. Unless the output is a true sinewave, the meter will be off.

If you have an AC generator, and you're half- or full- wave rectifying the resulting output, the reading will be all wonky as the signal doesn't go pos and neg.

A 16 volt (peak) full wave rectified signal will most likely read about 6 to 7 volts RMS on an AC voltmeter (maybe a bit more), since the meter will self-center at half the average voltage value, and read an RMS value of the resulting voltage swings. That 16 volts will most likely be fine for charging a battery, though, since the peaks are all positive, and any load will smooth out the teeth.

I would suggest putting an old battery onto the outputs, and then see what the meter reads.

jky