Originally Posted by BillBoost37
Without knowing what you have that'* sucking the power that hard... it'* tough to say.
Yep, give us the juicy details and we can better help you.
Also you have to understand that the alternator provides more flowing power, while the battery provides more storage. Adding a battery does not add to your voltage, just storage.
Generally people with big audio systems will have second batteries for two reasons:
1: So they don't kill the main battery while the engine isn't running
2: The second battery is a performance battery that can charge/discharge quicker thus helping to hold the voltage up during heavy bass or power draw.
With the alternator (and some bigger power wiring all around) you will alleviate voltage drop and dimming lights. With the battery you will allow the system to run longer without running out of juice and also with a performance audio battery you will be able to better sustain those moments of heavy draw.