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One wire Mopar Power Master alt.


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7:44 AM
Jul 19, 2008
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I have been running the Power Master one wire internal regulator one wire alt for about 2-1/2 years now. At 8 months it stopped charging so I checked it out and the internal reg was bad as its easy to test. They sent me a new one and all was fine until last week when I ran my 63 for a bit and noticed it was charging at 18 volts !! Unhook the green wire that the internal reg sends voltage into the field as the other brush is grounded. It stops charging and of course if I jump volts into the field it charges a ton. So I call them and its out of the 1 year warranty but Power Master says if I send them the alt they will check it and replace the reg but I pay shipping and the part. I said no thanks and decided to just wire the external Mopar electronic reg back into it. So I pull one of the ungrounded insulated brushes from my original alt and put both insulated brushes in my 100 amp alt. I wired it up using a relay so I took power right from my battery cable coming up from my trunk mounted battery. That way the reg and the field get 12 volts right from the battery and not through the ign switch so the reg has a better battery volt sense. Then I wire the relay to the ign switch key on volts so of course it turns on when the key is on. And it works great and charges just the same but since I have heard of others having trouble with the internal reg I figured after two gave me trouble I will just wire the external reg back in. Works great and I still get to use the Mopar alt so it looks more stock and original then using a jap or GM alt. Its nice that at night with the lights all on and the electric fan on the volts still stays at 14.2 at idle when the stock alt it would drop some at idle at night in gear with everything on. Course as soon as you hit the gas it would come back up and it never gave me any charging trouble with the stock 35 to 40 amp alt but I like that this one will charge more at idle and always stays from 14 to 14.5 all the time. Ron
Hence why still preffer external stock regulators against those who preffer internal just to save ONE or TWO wires from the harness over the engine. For me it makes no sense just because a… “cleaner look”? Because there is still a harness running over the engine with in some cases 6 wires more!!! Black ( alt post ), violet ( temp sender ), Brown/Blue ( + coil ), tan and brown ( dist if ECU ), black traced yellow ( - coil ).

on firewall, just saving the mounted reg and couple of wires leaving the harness tape.

Easier to service and solve problems on the road
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I really dont care if it was internal regulator or external as the wiring for the external did not bother me at all. I just like the 100 amp Mopar alt they sold and since it happened to be one wire so be it. But as said it seems that internal reg they use in that alt is not perfected yet. If that alt had come as needed the external alt I would have bought it that way. And since the alt still works perfect I feel better going to the well working external reg. This way I still have the high output 100 amp alt. Ron
Sure, is just about prefferences :drinks:

Is good it can be rewired to get it external as it came originaly. I have seen those how are feeded by a wire coming from inside
i have been running the same one wire as you got . what size wire did you use to go from the alt to the battery . i used 8 gage wire from the battery to the alt . and a 12 gage wire for the ground .
i have been running the same one wire as you got . what size wire did you use to go from the alt to the battery . i used 8 gage wire from the battery to the alt . and a 12 gage wire for the ground .

I actually used normal size battery cable (6 gauge) for my alt output wire and have 3 body to eng grounds. One is 6 gauge and the other two are 10 gauge. Cant have to many grounds as I like to have more then one just in case one would break or come loose. My battery is in the trunk and I put two insulated post studs on my firewall and ran the battery cables from the trunk right to my post on the firewall. That way I have a direct hot and ground right on the firewall and the feed for the car hooks to the pos post. The ground also has one come off the ground post stud on firewall to bellhousing for eng ground and one to the fenderwell for body ground. I dont have a pic host right now but I will try to post a link. I also use a relay to rewire the external reg on my 100 amp alt so it gets a good battery volt reading right off the pos stud on the firewall. And for my starter I ran a seperate battery cable that I use a Ford style starter solenoid in the trunk so the battery cable to the starter is only hot when the eng is cranking. I have also bypassed my amp gauge and have put a voltmeter in the car. Ron

See if this works.
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for sure 6 awg wire if your battery is in the trunk