i have a yellow top and a power acoustiks 10 farad cap and my head lights pretty much look like im turning my high beams on and off i have 2 solox 10"s with 2 hifonics brutus ran to 1 ohm and a 800 watt amp for my highs with 1/0 awg all the way around, my amps aren't even turn up all the way, there only at half way. i still have the stock ranger alt. but i dont really think i need a new one because it push 14.4 volts, so i dont know.
you need to upgrade your battery and alternator and wiring for them depending on what brutus amp you have. Most stock alternators don't run over 100 amperes, and your system if its the biggest brutus then its running much more than that and your charging system can not keep up.
A general way is to take your amps max output and divide it by your charging system (usually 13.8v) in this example, using the weakest brutus amp results in around 90 amperes drawn. and the strongest is around 350 amperes. so you need to determine how much current your actual system + car accessories are pulling and then go from there.