I have a 2 new interstate group 41 batteries and the stereo is hooked up exclusively to the aux. battery. That battery goes completely dead overnight without any other usage beyond the clock on the stereo. Do I have a short? Has anyone encountered this before? The battery is new and was tested at the Interstate battery dealer when I purchased it. It is annoying considering I know the battery is going to die from being 100% discharged too many times.