Without getting technicall. Most of the car audio batts will fix the "lights dimming" thing, the difference between the smaller ones and larger ones is the "storage capcity" So 32HZ, full volume for 10sec. may be ok for smaller batts before they are completly drained. but Play "White Girl" by Jeezey and ur FK'd, because you will discharge ur battery quick, and not be able to recharge it before the next bass note comes in because ur alt isnt big enough. If you want to cheat, go with larger batteries and several of them to gain mass storage. You'll get more time under a load to Jam out. But once you see voltage drop you gotta lay of 'em becuse your alt cant charge fast enough. The correct way to handle all of it, is to have an alt matched to your amp current draw while using the batteries as power storage. This way The bass hits........batts start to drain.......that 2 seconds where the bass stops.......batts are charging... and quickly......then bass hits again..... and you still have juice left.. Just understand that lower bass notes demand more "current draw" (take more power), so if thats what u want, u gotta get the ass behind the amps.