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Author Topic: DC lighting with 4 wire alternator  (Read 1118 times)


  • Bulleteer
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Re: DC lighting with 4 wire alternator
« Reply #15 on: September 20, 2013, 04:28:55 pm »
The zener will be lightly loaded, the transistor takes all the load. The capacitor will ensure I can run without a battery in emergencies.
I would ideally prefer to keep the OEM rec-reg unit, but the thing is it has failed in the past for no apparent reason, and it's a black box - Black boxes always worry me. 

I'm going to make it as simple as it possibly can be, as I said, just 3 wires on the main harness - 1 DC wire, 1 ground,  and one multicore singlestrand lan cable that brings signals to the toolbox to control stuff in the back that is controlled from the front and vice versa.
No taped or soldered or spliced connections. everything screwed or plugged in with good connectors.

I'll have to figure out how to fit several solid state relays up front, these are quite big and may not fit easily inside the headlight dome. Worst case I'll use MOSFETS instead of relays.

I'll need 1 relay for the ignition switch, 1 for the kill switch, two for the headlamps, 1 for the horn. The ignition relay will be in the toolbox, since it has to control everything else. The killswitch relay also lives in the toolbox.
The other three have to be up front.

I ordered a small digital volt/amp meter for about 8$ that can be mounted easily, it will be useful to test and monitor the system on the road - I can probably use it for various other purposes, as a thermometer or oil temp sensor or maybe even an A/F sensor.

I think I will start off using the OEM Rec/Reg and build my own system later once I have the new wiring working as intended.


  • Grand Gearhead
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Re: DC lighting with 4 wire alternator
« Reply #16 on: September 20, 2013, 05:11:10 pm »
Sounds like a fun project. Now that I think about it, I seem to remember a circuit for a honda using a transitor set-up.  I will try and find the link in my files.
 If it doesn't work, you can re-install the SCR regulator.  Be sure to take some photos and post them.
« Last Edit: September 20, 2013, 05:14:36 pm by mrunderhill1975a »