head lights and cap

i have a 1.5 farad cap runnin to my 400x2 ppi amp and my head lights still dimming. any advice?

first off. Your cap is like a bettery. Its able to store voltage and gives it off it quick spurts when your amp needs it and gets charged back up in a split second. The only problem is that it also draws more from your alternator because now your alternator needs to charge your battery and the cap. Now depending on how you have your sub(s) wired will affect this. Obviously your amp will need more power for a 2 ohm load than a 4 ohm load. Your alternator might not be powerful enough.

so basically a stronger alternator is needed? i have 2 w6 10s runnin off the ppi . subs are in series

Does it matter if the cap is digital?

to check what your voltage is at with the music off  and when bass hits. If your cap drops down pretty low, then your alternator isnt powerful enough

yes and yes

it drops almost a volt thats bout it

if your voltage drops but then recovers quickly than I wouldn't worry. as long as its above 12.5 volts it is fine