Ok guys, I have searched the old posts and cant seem to find what I need. Using an internally regulated 3 wire alt as a 1 wire. It drains the battery. If I unplug the small short wire going inside the alt drain is gone. So I think I can either put a diode in that short wire so current will only flow one direction or take the wire to the switch so it is disconnected when switch is off. Is this right?
I thought they had to be coverted to 1 wire with a plug setup that probably contains a diode. Never saw a viable reason to run a one wire alternator unless it was on a farm tractor with a magnito like they were originally designed to be put on. Every 1 wire alternator designed for 1 wire hook up has a plug similar to the one in this photo This is pretty much a standard 3 wire hookup with light. This I believe is what you are asking about.
I never saw the attraction of a 1-wire alternator outside of stock cars. Most wiring kits are set up for a 3-wire, but you can do them as a 1-wire losing the exciter wire, IIRC.
The alternator will work better (as designed) if you leave it 3-wire and connect properly. Just two additional wires and a diode and/or a 194 bulb. You can change the regulator to convert to 1 wire, if you insist on one-wire.
If you run the #2 terminal of the plug to a junction block as close to where all the accessories are connected you get the added benefit of voltage sensing. Voltage sensing detects a drop in voltage where ever the sensing wire is connected and boosts alternator output to compensate for the voltage drop in long runs of wire. If connected at the alternator, it is sensing voltage right at the alternator so you could have less then optimum voltage down the line where it is being used.
If you wire the 3 wire alternator like Mr48 shows you will only add 1 wire. If you ran that wire through a bulb you would gain an idiot light. Or you could use the diode. Either way it is only one added wire.
You could wire the exciter wire to the accessory terminal on ignition switch without diode or lamp in series. Also the sense wire should be routed TO the closest it can be to the battery. That way the battery will have correct charging voltage.
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