battery and alternator

Start with the Alternator like VM said.

Then take a total amperage draw from your system (just add the fuses) add 50 amps to that (for the car and possible misc equipment on it.). If your alternator output is higher than the total, a cap will not be required but recommended. If your alternator is less than the total but within 30-35 amps upgrade the cap. If more than 35 amps below the total, then upgrade the battery next.

We recommend 1.5 Farads for every 1000 watts. Industry "standard" is 1 Farad for every 1000 watts. It doesn't as big a strain as many would have you believe. It'll actually help out and give you a 70 amp boost for a second without fluctuating the voltage. Second, draining it completely doesn't deep cycle them unlike regular car batteries. So you can keep up the pump on different days will minimal if any effect. Batteries give you a long boost time, but they unfortunately deep cycle and lose some energy capacity (averages 10-20% drop in capacity, If 2 or more cells go bad in the battery, then the battery will need to be replaced or it can cause problems for the vehicle).