voltage across battery when charging ?

[mpj76]

I once had a very old style (1970's) 130 amp alternator with an external voltage regulator. During my heater core swap job, I drove the car without the instrument cluster connected for about 2 days. Turns out that the alternator was excited by a charge on the same ciricuit as the cluster. Without this circuit closed, I had to blip the throttle to about 4-5000 RPMS to manually excite the alternator. I could also excite it by running a lead from the + battery terminal and touching one of the terminals on the regulator. If you're running an adequate gauge of wire and have good connections, you may have a similar problem.