When it comes to Cars with the under glow, interior glow, HID headlights, audio supplies and still the basic electric procedure, how can a 12 volt battery handle all of that with out dyeing all the time?

 

Except for big subwoofers, those mods really don't use much electricity. With really big audio setups it is common to upgrade the battery and alternator. While the engine is running, the car is actually powered by the alternator not the battery.