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Long story short, had my alternator quit working. It's a 3G 130A. I had it rebuilt, and initially upon starting the car it outputs 14-14.3 volts according to the gauge on my Holley HP. As the car gets hot when driving, especially in stop and go the Voltage eventually will drop do low 13's. Which I understand at this point, the fuel pump is getting warm, the cooling fans are on, my electric waterpump is on. The alternator is only about 1cm away from the header (forward facing turbo headers) so maybe its getting too hot? The 13ish volts I know isnt too low, but after a drive and the car at an idle sitting with the fans running it pops the 150A breaker I have in the trunk right before the wire goes to my cutoff switch. I have 2ga wire running from the alternator to this breaker, then to the cutoff switch. Why am I blowing a 150A breaker with a 130A alternator? Why would it be even remotely close to pulling that much amperage. I'm running a Mark 8 fan with a DCC controller, Mezeire electric waterpump, Magnafuel protuner 750 and the Holley HP efi system. I dont see the electrical load being that high to pop the breaker.

Battery is a 850CCA AGM, battery cable are 1/0 ran from battery to solenoid and ground from battery is 1/0 and ran to the back of the head.

So the only thing I can think is the heat from the header, or maybe I need to run a ground to the framerail from the motor as well?

Any ideas/suggestions
 

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With the system warm and running at a good fast idle or simulating "low cruise," turn on some load, whatever you have, fans, headlights, etc and see what the DC voltage is

Then switch your meter to AC volts THAT'S RIGHT AC volts. and check a couple of places, at the battery and alternator, and post what you read.

I don't even recall what max allowable should be but "very little" a few millivolts

An open or shorted diode, or other internal problems like a shorted phase winding, will cause a bunch more AC ripple
 

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With the system warm and running at a good fast idle or simulating "low cruise," turn on some load, whatever you have, fans, headlights, etc and see what the DC voltage is

Then switch your meter to AC volts THAT'S RIGHT AC volts. and check a couple of places, at the battery and alternator, and post what you read.

I don't even recall what max allowable should be but "very little" a few millivolts

An open or shorted diode, or other internal problems like a shorted phase winding, will cause a bunch more AC ripple
I had this happen to me and I had the Local starter/alternator shop test mine. It would be totally normal until about 50 amps load then one of the diodes would loose connection and it would go wacky. they tested it a few times and under 50 amps it would be just fine. They resoldered the diode connections and it was perfect after that.
 
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