I'm asking a question here. ok ... Is the alternator suppost to charge the batteries during or after heavy use? stereo or regular vechicle activities? I'm wondering how it (alternator)can stop voltage drop when its job is to charge the batteries. I have five batteries, 2 in front, 3 in rear, on a 200 amp alt. Over a year with no problems. I'm asking this because it might help the op to understand his problem. Plus I would like to the way this works. I'm an electronics tech. but I'm kinda drawing a blank on this one for some reason. Can somebody please help?