Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties Harley generator

Harley generator

Moderators: Curt!, Pa

Post Wed Dec 14, 2011 3:21 am

Posts: 41
Is it possible to run the lights off the generator and without a battery in the circuit? I am using magneto ignition and would like to have a simple system running just headlight and rear light but without a battery. My generator is a 32E 6V which is not working at the moment, so I might go to 12V electrics. Any advice and tips would be appreciated, thanks!

Post Wed Dec 14, 2011 8:19 am

Posts: 386
Easy with 12V but you can also rewire the 32E for 2 brush operation and it will work. You need the appropriate regulator, and your lights will dim at idle. There is a lot of info out there on this set-up. Search the forum and you will find more. I ran set-ups like that for years using a 2 brush 6V and a Harley Sprint regulator.

Post Wed Dec 14, 2011 10:05 am

Posts: 41
Thanks Robbie, much appreciated. Regards, Joseph.

Post Tue Dec 27, 2011 1:27 am

Posts: 41
Apart from blowing bulbs, would the 32E generator suffer damage if it is used without a battery and regulator? If the engine is running, does the generator need to be connected to a circuit to prevent damage to it? Thanks.

Post Sun Jan 08, 2012 12:38 am

Posts: 2677
Location: Los Angeles, CA
You run a capacitor in the system to control power surges.

Post Sun Jan 08, 2012 9:47 am

Posts: 41
Here is what I did so far: I am taking current from the relay post of the 32E generator directly to front and rear lights. I put 12V bulbs in. There is no battery, no capacitor and no voltage regulator in the circuit. The lights are dim at idle and get brighter when the engine revs, but so far I haven't blown any bulbs.

Would I be damaging the generator if the lights aren't switched on all the time the engine is running? I don't mind burning a bulb now and then, but would hate to damage the 70yr old genny :(

Post Mon Jan 09, 2012 7:03 pm

Posts: 1645
Location: Interlaken, NY USA

You really ought to run a regulator on the genny, I'm surprised you haven't blown a bulb yet. Yes, 70 volts for long periods might eventually find a weak spot in your genny's insulation, and cause it to short out.

Post Tue Jan 10, 2012 3:36 pm

Posts: 159
You'll throw the solder off the commutator eventually.

Post Wed Jan 11, 2012 12:44 am

Posts: 41
I adjusted the third brush so that even when the motor is revved up (at considerably more than cruising speed), the output does not exceed 20V. So far, the 12V bulbs have held up. But maybe its better to keep on the lights all the time for the generator's sake. Thanks for all your advice.

Post Wed Jan 11, 2012 5:41 am

Posts: 1645
Location: Interlaken, NY USA

As to keeping the lights on all the time, that may not be a great solution.
Your problems are twofold:
1)Running enough load to cause the armature to heat up and "throw" the solder from the commutator. "Might" happen if the lights are on all the time, at the increased voltage. The enemy here is heat, which is determined by power dissipated by the genny. In math terms, P=IV, power dissipated equals amps drawn times voltage.

2) Excessive voltage causing arcing in the generator, exceeding the breakdown voltage of the insulation of the windings. Not likely at the 20 volts you claim, but, that is 3 times the rated output voltage of the device.

Your call, it's your machine, and you may get many happy miles with no problems. These 32E's are a very robust design, and I've abused them most every way possible over the last 38 years, including the configuration you're running. Personally, I finally settled for a small gell cell and regulator.
Happy Motoring!

Post Wed Jan 11, 2012 5:46 am

Posts: 41
Thanks for the sound advice, much appreciated :)



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