Step 1:- Remove Cap From Packaging.
Step 2:- Find a door that wont stay open.
Step 3:- Place Cap in front of door to stop it shutting.
Moral of the story is if you need to capacitate more power because you are Drawing more than 1000 Watts "RMS" Then you need to do the Big three (upgrade cables between Battery- Alternator, Battery- Gnd and Alt-Gnd) Then you will need to add a second battery in the boot.
Power caps have no place in a car, they just drain the power and cant replenish it quick enough.