Join Date: Jul 2005
Location: Winston-Salem, NC
Alternator, voltage output question.
Ok, so I installed a March under drive serpentine setup. My voltage used to run 14+ volts(while driving) with the under drive pulleys it was around 11 volts(while driving). I swapped out the alternator pulley for one that was the same size(actually a little smaller) as my old one and I wired my alternator to be a 3 wire, yet I still only run about 12.5 volts(while driving). My water pump pulley is the same size as the old one and the crank pulley is only 1/4" smaller, so it shouldn't be under driving the alternator any more. Last night I had it out after dark and my gauge was showing about 11.5 with the headlights on.
When the car is running I have 12.4 at the battery and the alternator. Pretty much every where else is getting 11.9-12.1. I drove the car about 175 miles with it under driven and only putting out 11.4 at the alternator. Do you think I damaged it. It is a Powermaster, I don't know what amp. I looked a part number on it, but can't find one.
I wired the 3 wires up with the one blade looped back into the charge stud and the other is being fed from a switched source from the fuse panel and has a 3amp diode. I have a 4ga wire from the charge stud to the starter lug, cause my battery is in the trunk. It hasn't left me stranded yet and starts fine. I just figure it will preform better with more voltage.
Can anybody find a flaw in anything or is the alternator going/gone bad? I can get the alternator check at pretty much any parts store, right? When tested it should put out, what? 14+ volts. Thanks all.