I have a five month old battery that I've had tested several times and appears good. But won't start the car, as if it were low. I've watched a voltmeter as I turned on the accessories and its starts draining immediately. The car can be jumped off from another running car. If I had a true short I'd think it would blow a fuse first before draining battery that fast. I'm out of options before I take it to the dealer and looking for suggestions.