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Alternator/Charging system circuit

Old 08-16-09, 03:20 PM
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Alternator/Charging system circuit


I am looking for information, on how others have wired up their Alternators, on a race setup... I have an ARC Switch panel, remote mounted battery behind pass. Seat, and am running a Series 6(FD) Alternator. The EMS is Haltech, so the stock harness has been removed.

Engine is 13BRE, with Mazda racing Alum pulley set(serpentine) and I believe are slightly underdriven. I previously had a S5 engine as the chassis is a FC3S 2nd Gen. So the pulley ratios, as I have noticed, are slightly different from the FC to the FD. The car will still charge at idle, but I have been having issues with it continually charging.

If I drive the car for a short while, the Alt. will cut out, and voltage will drop as a result. I have put an LED inline from a separate switched power source, to the excitor on the two pin plug. This will get the Alt to charge, but after some driving.... cuts out.

Any input on this would be great, and if anyone can post up their charging circuit, with wire gauges, dummy lights, etc... sparing no detail, that might help me find something I possibly missed.

Thank you in advance.
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Old 08-17-09, 01:51 AM
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it almost sounds like an alternator fault,once the alt is charging(as in been excited thu a light or led)it should keep charging even if the two pin plug is disconnected as long as there is a good engine earth and a good positive supply to the main stud(with wire cable heavy enough to support 120amps)if there is an intermitint break in the main feed this would cause problems,ive always just wired my alt dirrectly to the battery thu a fuse link,hooked up a 12v 2w warning lamp to the "L" terminal with a switched(eg ing switch) feed to the other side of the light,if the last wire in the two pin plug is listed as "S" the this can be wired to the alt main positive stud if its listed as "I" then it goes to the same switched feed as the warning light,hope this helps!
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