Good thought... don't own a trickle charger though... do I need to go get one... can I just leave my car running for a long time?

On that note, what do i need to do to prevent my battery from dying so quickly when the car is off with the stereo running? I'd like to be able to use it for music when I'm camping and whatnot for more than 15 minutes

Maybe add a capacitor or second battery? Has anyone done this with good results?