Battery Light Comes on...

[JaMo1982]

Hey sup ya'll. Got a quick question about my car.
It's a 2003 Ford Focus ZTS

Whenever I drive the car during the day with the a/c on, the batter light comes on. It only comes on after I hit about 60 mph and during the day. Once I go under that speed limit, the light turns off. If I try to simulate the same thing at night, the light doesn't come on. I'm just thinking of changing the battery because that's the only thing I would assume is wrong, even though I don't know why, but would it be something more?

[Sponsor]

[S2]

Got warranty left?

Could be a few things, battery, alternator, etc... best it to get the electrical system checked.