I'm having a battery voltage problem, according to the dash gauge, when I first start the car whether it be in the morning, afternoon or night. Weather conditions haven't effected anything. I know the factory gauge isn't completely accurate, but I can tell by the way the car runs. It runs very rough, as if it were about to die, but never actually does. The lights are dim, and every time the sub hits the gauge drops and comes back up. If I'm rolling down the windows the gauge slowly goes down until I let go of the switches. All of this only happens when I first start the car. If I rev or while cruising at a steady speed the voltage goes back to normal. Last time I checked the battery with a voltmeter it was around 13.

Any ideas?

 

My dad's Camaro has a similar issue, although not as severe. In my dad's case, it is the alternator. We got a new (reman. from a CarQuest) alternator, and a few days after installing it, it developed this problem.

When the car is first started, the alt does not function (low-ish voltage, from car running on battery only). To get it to start working, we just give the engine a quick rev to about 2500rpm or so. After that, it works just fine. Now, it might be less of an issue for us because we might have a newer or bigger battery than you, so it can handle running with no alt for a little while.

So, with that said, I guess I would reccommend you check or get the alternator checked. Let me know how it works out...

 

I'm having the same issue. New alternator. New battery. Can't figure this out. After revving at about 3k for about ten seconds it goes back to normal and stays strong.