In my last car I had a yellow top (Optima) with a high output alternator and was running a 1000w amp (subs) and a 400w amp cranked up all the time. Surprised I'm not deaf. This set up was for 4 years and the battery never failed. Had the system blasting at a wedding for hours with the car off before the voltage got too low to support the subs. Charged right back nicely, too.