Electrical charging system question, Alternator? Options

[rjames]

I installed a brand new battery and a new voltage regulater last week in the car. My volt meter is showing 12.5 volts at the terminals. With the car running and the lights and fan on my volt meter fluctuates between 12.7 and 12.9, then slowly starts to dip, getting as low as 12.5 before I decided to shut the engine off because I could see that the battery was slowly draining.

Would it be logical that the alternator might need replacing? The alt. belt also seemed tight (not sure exactly how tight it should feel though.) I can check the electrical connections (have to find them first though.) The connections at the battery all look good though.

It doesn't look like a fun job to replace the alternator, but I'm up for the challenge. Anything else I should look for before I go this route??

Thanks!

PS: Forgot to add that the alternator light on the dash comes on when starting the car, but goes off right away once it's started and doesn't come back on at all when driving.

[rjames]

OK, now I'm totally confused. I switched the relay board for another one that I was given awhile back. As soon as I plug it in I start the car, and measure 13.7 at the battery terminals. I think my problem is solved! After driving around for a few minutes at fairly high revs I check the voltage again, and now I'm back down to 12.5-12.7 and the turn signals don't light as bright verifying that yes, I have dropped back down to a lower voltage.

Relay board? Maybe? Could the alternator work well when the car starts, but gets 'tired' and can't keep up the charge? This would happen with the other relay board at times where it would show 13.7ish right when starting the car (after it had sat for awhile) and then drop down to 12.something after a couple of minutes.

Should I just change the friggin' alternator already? Could the alternator be working correctly for a minute or two when cold and then lose some of it's charging ability soon after?


Jeez, I'd rather be installing my sway bar then messing with this electrical crapola.