What farad capacitor should i buy with two 15" kicker L7's?

ok its easy to figure out what size capacitor you need. 1 farad recommended for a 1000rms of power if you system is 1500rms you use a 2 farad cap. a capacitor is used to store current and it doesn't only store it also discharges at high rates unlike a battery. a cap. is best for b amps when you need alot of power fast