Whenever I turn my car off and have the music playing my low battery warning comes on after15 minutes or soand not long after my car wont turn over. IF i boost it its fine after that but it always does this when turned off. I got a new interstate battery about a month ago. Any ideas?

 

These cars are not meant to play the radio long after the car is off.
There is anywhere from 15 to 20 computers pulling juice with the key on like that.