Lights Dimming

Hey My lights have been dimming just whenever my car uses any extra electricity other then what it needs to run lol and you just see the volt gauge move pretty dramatically but never goes below 10 but anyway at first the batterry was ****** to begi with if i used any elctricity other then interior lights when the car wasnt running the battery would not have enough juice to start it so the battery wouldnt hold the charge got a new battery can use whatever power i want for like 30 minutes and still start the car so the battery is good but the lights still dim and whatnot and when the really low bass notes hit you see the gauge move so anyway cutting to the chase.....some people say install a capacitor, and some people say that it will just draw more power, and some people say get a second battery so just wanted to get some oppinions thanks.

do the big 3 if you havent done it yet (search it on here if youre not familiar)
and get a 2nd battery according to the power youre running

---------- Post added at 12:57 AM ---------- Previous post was at 12:57 AM ----------

BTW, knowing what kind of car and what your current system is helps with specifics A LOT

i have not done that yet and i have a 96 Camaro w/ Kenwood deck and 7 band eq, Boston Acoustic 6.5's, 3 10" JL's, MTX 4244 &MTX 6500d