I spoke to a student with a ghetto-blastin' truck stereo today and he has 2 batteries and a cap for each of 3 amps 1500 watts worth RMS. He says the only way these rigs work is with a cap for each amp. They deliver (discharge) power 5 times faster than a battery.

Articles for your perusal:

http://ezinearticles.com/?Understand...tors&id=374955

http://ezinearticles.com/?Car-Audio-...-Them&id=74789

http://www.caraudiohelp.com/car_audi...stallation.htm

Hope this helps.