Generator/regulator question

notjustair

Well-known Member
It's time for me to switch the 58 GMC grain truck over to an alternator. It still has its 12 volt generator and Delco Remy regulator. The truck is all original but gets used so it needs an upgrade. Right now it's my water truck for remote stock tanks and I can't leave it idle with the lights on. The generator also needs a rebuild as it has an intermittent short and I'm not putting the money into it.

Anyway, I'm going to put a 10si on it. I don't want to cobble the wiring. Can I run a wire from the alternator over to where the regulator is and use it as a junction to the wiring loom? I was thinking about disconnecting the field and arm wires, leaving the "bat" wire attached to the regulator and putting the line from the alternator under the same screw with a crimp on spade. This way all of the wiring would be fed the same as it always has. My question is whether having only the battery terminal hooked up at the regulator could cause a parasitic draw?

I could run new wires but everything there is in good shape and functions correctly. I don't want to cobble up an otherwise original truck with 77,000 miles on it. Someday at my farm sale some nut like me could buy it and return it to original if I haven't gone through and cut up the original wiring connectors. When I switched one of my old tractors over I did something similar - I used the existing wiring to make all of the connections. I'm just not sure about using the battery terminal as a junction block if nothing else is hooked to the regulator.
 
(quoted from post at 23:32:36 10/04/16) It's time for me to switch the 58 GMC grain truck over to an alternator. It still has its 12 volt generator and Delco Remy regulator. The truck is all original but gets used so it needs an upgrade. Right now it's my water truck for remote stock tanks and I can't leave it idle with the lights on. The generator also needs a rebuild as it has an intermittent short and I'm not putting the money into it.

Anyway, I'm going to put a 10si on it. I don't want to cobble the wiring. Can I run a wire from the alternator over to where the regulator is and use it as a junction to the wiring loom? I was thinking about disconnecting the field and arm wires, leaving the "bat" wire attached to the regulator and putting the line from the alternator under the same screw with a crimp on spade. This way all of the wiring would be fed the same as it always has. My question is whether having only the battery terminal hooked up at the regulator could cause a parasitic draw?

I could run new wires but everything there is in good shape and functions correctly. I don't want to cobble up an otherwise original truck with 77,000 miles on it. Someday at my farm sale some nut like me could buy it and return it to original if I haven't gone through and cut up the original wiring connectors. When I switched one of my old tractors over I did something similar - I used the existing wiring to make all of the connections. I'm just not sure about using the battery terminal as a junction block if nothing else is hooked to the regulator.
hould be just fine. The BATT terminal on the VR is connected to nothing inside the VR unless the generator applied enough voltage on the ARM terminal to pull im the cut out relay. You could ever utilize the generator ARM to VR ARM wire to connect alternator output to the VR's BATT terminal, and save running another wire.
 
Been working since 58 seems like if the gen was refreshed it woulkd probably last for another 50 pluss yrs with no wiring changes ect cant cost that much to refresh the gen.
 
YOUR QUESTIONS:

"Can I run a wire from the alternator over to where the regulator is and use it as a junction to the wiring loom?"

YES, the wire that's attached to BAT on the old VR is what leads up to the battery and/or ammeter if so equipped and is where the big main output stud on an alternator would be wired.

NOTE when I make such an upgrade if not already there, I like to upgrade that wire to at least 10 gauge.

"I was thinking about disconnecting the field and arm wires, leaving the "bat" wire attached to the regulator and putting the line from the alternator under the same screw with a crimp on spade. This way all of the wiring would be fed the same as it always has."

WORKS FOR ME subject to the upgrade above

"My question is whether having only the battery terminal hooked up at the regulator could cause a parasitic draw?"

If alls well in the old VR ??? that shouldn't create any parasitic draw. The VR's BAT terminal doesn't electrically attach to anything until such time the Cutout Relay closes which shouldn't ever happen in your case.

John T
 
This diagram, compliments of Farmall Bob shows how to do it on an Farmall Super M. The wiring basics would be the same on your truck.
05-12vAlternatorConv-rev4_22_08.gif
 
If it has a 4 terminal regulator with L terminal, the L supplies power to light and ignition switches. Move this wire from L to BAT output to power the switches
 

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