Re: [MV] 6v to 12v conversion info

Dave Cole (
Thu, 23 Jul 1998 14:14:29 -0400

OK, I guess I need to ask. But what is the great appeal of a one wire
alternator. If you use a late 70's-mid 80's internally regulated GM Delc=
alternator (about $30-45 buck rebuilt) it only requires 3 wires. =

1. Wire from battery to alternator - usually large red 8-10 ga wire - mai=
power wire
2. Wire from side plastic connector directly to battery - voltage sense
wire =

3. Wire from side plastic connector to ignition switch

Alternator case is assumed to be grounded to the engine block to the
battery to the (-) terminal.

That's three wires, then if you cheat, like a lot of farmers do on their
farm tractor conversions, you tie the battery sense wire from the plastic=

connector to the big "bat" terminal on the back of the alternator. This
means that the internal voltage regulator regulates voltage at the "bat"
terminal rather than the battery terminal itself, so the battery might no=
get quite as many volts, but this should be insignificant if everything i=
working ok. Then you are down to two wires. I personally wouldn't pay =
or 20 bucks to save one or two wires, but then that is me. Plus, if you
use a standard off the shelf delcotron alternator and you happen to break=

down in Nowhere, USA you can just find a local mom and pop parts place,
stick in another alternator and away you go. =

Also, anytime the diodes in a GM alternator start to fail, they will leak=

current from the "bat" terminal to ground and eventually kill the battery=
=2E =

I found that the diodes also fail when you try and jump a GM car with the=

jumper cable leads reversed, but that's another story. (;->) =

My two cents.


Message text written by
>If you use a 1 wire alternator I suggest running the wire through a cuto=

switch before the battery. This allows you to isolate the alternator when=

not running. In some installations (and each is unique even on the same =

model vehicle) when the engine is off the alternator will "reverse" the =

flow of current and drain the battery. Not a normal thing but does happen=

(personal experience taught me this lesson) and it a PAIN to do the
go where you want, and find the battery dead faaaaaaar from the barn whe=
n =

you want to go home. If it drains long enough not even a jump will help, =

the battery is just a write off.

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