I am pretty sure that it is running off of the battery. The belt is not getting wet and I am metering the larger red and black on the alternator and getting those readings. The smaller connection into the back of the alternator (red and purple wire on a plug) both the purple and red are putting out 12 volts. If i put the positive lead to the purple and the negative lead to a engine bolt I get 12 volts and the same on the smaller red wire with engine running 2500 rpm and at idle. I left the meter hooked up to the alternator with the engine running 2500rpm and at idle and still getting the same readings at the alternator. Could i have a bad new alternator? As far as the stereo goes I only have a deck and it is isolated on a switch, no amps or subs.