I think something's up with my alternator. Whenever I start my car for the first time in the day or after its been sitting in the cold for a few hours, the battery meter is at about 8-10volts and the battery light comes on. It will go away after about 5 minutes of idling or 3 minutes of driving. After those few minutes it'll just pop up to the center of the meter and stay solid there. The few moments before the needle goes where it should, it will fluctuate with the rpm's of the engine. But once it reaches the point where it should be it stays there and doesnt drop back down. It did this a few times last winter when it was really cold, but it's beginning to do it now often and in 65* weather. I just replaced the battery a couple weeks ago and I dont wanna waste it. What can I check? What could it be?