Battery lamp keeps coming on

I have an 04 325ci and red battery light keeps coming on from time to time. The car still runs and after I drive it for 5 mins or so, I turn off the car and turn it back on and the light stays off for a few days until it decides to come back on. I don't notice a loss in power either. What could this be?

__________________
This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW Alternator Troubleshooting and Replacement

[Wayne 962]

I'm not sure - it could be the battery, or it could be the alternator. I would probably replace the battery first and see if that fixes the problem. If the battery is original, it may be time to replace it anyways.

- Wayne