If you look at the amp, it will list a figure called "current drain", listed in amps. That is how much that amp will suck away from the alternator. And Carpepoon is right, never go buy what the cover says. Go by the RMS watts. Peak watts mean squat.

Scott Mabe I WILL be Phil. 1999 Contour SVT, Tropic Green BAT kit, K&N RU-3530+MAF, Magnecore 8.5mm, some audio goodies, Hightowers, Knauberized, tatoo by Parkedcar.