12V conversion wiring shortcut

mkirsch · Jul 31, 2012

I want to do a quickie 12V conversion on Dad's W400.
1. The battery's shot.
2. The old charging system isn't working 100%.
3. All the parts to convert to 12V, including the battery, cost about the same as the big honkin' 6V battery.

If I simply take the wire from the GEN terminal on the regulator, and move it over to the BAT terminal on the regulator, will that effectively bypass the regulator?

I would then transfer the wire from the A terminal on the generator to the BAT terminal on the alternator and use that as my main charging line.

From Bob M's schematics, it looks like it would work.

Phil Tibbetts · Jul 31, 2012

Spring for a single wire alternator and all you need is a wire from the alternator to battery nothing in between. then replace your amp meter with a volt meter. I like the volt meter better than the amp meter. IMO

MCOHIO · Jul 31, 2012

A properly working 12 volt generator will put out well over 12 volts during operation. I have had a few that tested 19 volts. You need the regulator to keep from over charging your battery.

Phil Tibbetts · Jul 31, 2012

One more thing don't forget the ballast resistor between ignition wire and coil.

John T · Jul 31, 2012

If I simply take the wire from the GEN terminal on the regulator, and move it over to the BAT terminal on the regulator, will that effectively bypass the regulator?

YES that by passes the Cutout Relay portion of the Voltage Regulator (its between BAT and GEN). If you do that the hot ungrounded battery feed via the ammeter which is present on the BAT terminal, is then connected to whatever you then connect that terminal to, such as say the output of an alternator...........

DONT FORGET MOST ALTERNATORS ARE FOR NEG GROUND so if the tractor were at Pos Ground??? you would have to swap ammeter leads or it will register bass ackwards

If a tractor has a coil ignition and you changed polarity, the coil leads would also need swapped HOWEVER if youre already at neg ground (like on most 12 volt tractors) neither of the above swaps are necessary

John T

mkirsch · Aug 1, 2012

Thanks John T. I didn't want to cloud the question with all the pesky details.

Any one-wire alternator: $150
Remanufactured three-wire alternator: $30

I also plan on:

1. Adding a ballast resistor to the coil supply wire.
2. Running a wire and diode from the 12V side of the ballast resistor to the alternator 1 terminal for excite.
3. Connecting the alternator BAT terminal to the alternator 2 terminal.
4. Reversing the connections on the coil.
5. Converting to - ground.

12V conversion wiring shortcut

mkirsch

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Phil Tibbetts

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MCOHIO

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Phil Tibbetts

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John T

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mkirsch

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