I've arranged to get battery charged tomorrow. If I do so and the red battery light goes, does that mean I need to change the battery and it's not the alternator? I agree with you, I'll get the battery tested regardles. However, the manual says, "Red: stop the car as soon as possible. the battery is not being charged. The alternator V-belt is defective or there is a fault in the alternator charging cicuit. Consult the nearest BMW Service."