Alternator problem?
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Alternator problem?
My '77 has a rebuilt alternator that is only a few years old. I'm afraid that there is a problem with it that killed my old battery. The voltmeter on the dash reads around 15.5v - right at the bottom of the upper yellow zone. Is this a bit high? I was under the impression it should run around 14.5v. The charge rate didn't change with the new battery this morning. If it is overcharging, is there any way to adjust the internal regulator output, or do I need to go get another alternator?
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
It should be around 14v max. I'd measure the actual voltage with a separate meter to see if the output is really 15.5v. If it is, you will "cook" your battery and have double the expense. I don't know about *adjusting* the regulator output, but I think you can get it replaced depending on alternator type.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Tested the alternator today, it is putting out 14.63v at idle. The Haynes manual says 14v-15v is okay. I'm going to take it to the parts store for a more detailed test.
