Battery Light comes On but only a few Times

I drive a 99 Grand Am SE, this past summer I had both the alternator and battery replaced. Just yesterday, I started my car, after it had been sitting for about 12 hrs, and began to drive and the battery light came on. After driving a few minutes it went out but then came on again. I stopped my car and restarted it and it came on after a few moments but then went out and didn't come on the rest of the day. I drove my car at least 3 times after that and the light never came on. Today, I drove my car after it had been sitting for about 24 hrs. And the light didn't come on. But the next time I drove it, a few hours later, it came on and remained on for my trip, about 10mins. I checked the belts and couldn't see anything wrong. I was wondering what could be causing this. Is it because of low temperatures or because I need to run my car longer before starting to drive?