2002 Saturn L200 Battery Light

My battery light will periodically turn on and off while driving. I have noticed it comes on while I am driving/accelerating down the road. It seems to (not always) turn off while I'm stopped at a light or idling. I replaced the alternator last year and the battery 2 years ago. So I'm confused as to what it could be. I'm looking to sell the car so I would like to get the remedied before I sell it.

Thanks for your help!