thats alot of power taken away from the bayttery and workin the alrernator.. try a battery thats bigger than your cars battery, but can still fit. my autoshop teacher said running 1000 watt amps with a tiny civic tape player battery is like death to the alternator. or try running 2 small batteries, it will hold power longer and have less stress on the alternator... its your decision i guess.. would you spend a few bucks on a bigger battery or 2 batteries; with less headlight dimming, or would you want have less weight on the car and pay a couple of hundred bucks for a alternator in the long run. or you can try alrernators with better amps