Also it not a good idea to mix batteries in a car. IE:-Optima(gel type) --Standard (acid type) as the car will charge the weaker battery first and wont fully charge the optima, There are new Batteries from PULSE the will in the standard location with a higher reserve for stereo's, I have a optima tha i have had for 3 years now and i can have the stereo running @ 3/4 volume at shows for over 4 hours and still have no worries starting.