In article ,
"Kim Inglar" wrote:

Why do you use a capacitor? what is it good for? And do you realy have nead
for it if you have large batteries?


They attempt to hold the voltage steady. Unfortunately they have
minimal value for car audio amps. If the voltage is drooping from thin
wire, the better solution is bigger wire. If the voltage is drooping at
the battery, you're drawing too much current for a capacitor to be
useful. (You probably need a more efficient system if you're loading
down the battery!)

A capacitor doesn't do anything to help the alternator. They don't
store nearly enough power for that.

One farad is the capacitance where 1 amp causes a 1 volt/second change.
A 1/60 second surge at 60A would drain a 1F cap 1V or a 2F cap 0.5V.