Actuallly i dont have a shop yet but basically a cap works that way it helps your battery by supporting your amps power w/o having to use your battery all the time. So u can play your system for a while while your car is off and not loose voltage in your battery.
Lol, that might be the dumbest thing I've ever heard. Do you know where the cap gets its current from? The alternator. When your car isn't running, the system runs directly off of the battery, so using a cap for when the car is off is basically pointless, considering that the cap will draw power from the battery when the car is off.
Actually all it does is help your battery basically to get more voltage to your amps. Trust me iv installed my fair share of caps and know how they work. Basically they are an extra battery that helps out with voltage to amps.