I have never touched my battery under the hood and don't plan to for as long as possible due to the fact it is under my windshield wiper fluid. However I have a back up battery in the back hooked up through a battery isolator. One time my start up battery died at my friends house with the music at a decent level so I assumed it was because my interiors were on for too long. However then it happened again when i was testing my new boxes, only this time I saw my back up battery ground came unhooked. Could this cause my start up battery to be drained...even then shouldn't the isolator prevent this.
