again second battery post

What runs the electronics while the car is running?                        Alternator.

The battery basically comes into play only when the alternator cannot supply the power, generally your electronics should be running off your alternator, if the alternator cannot supply all the power the battery will eventually drain and die. When you see lights dimming its because the alternator is overworked and you are starting to draw from your battery which rests at a lower voltage resulting in lights dimming, bass getting muddy, and amps getting hotter.2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

yes, all car batteries rest at 12.6 volts (6 cells at 2.1 volts each), what you need to do is get  a high-output alternator.

sprahl ur way off... u could hook two batts together and run them at 24volts.. but u wouldn't have any wiring in your car left... a car is only made to handle the 14 volts.. and if u make a bad attempt to use some sort of rectifier it wouldn't work as u stated urself that its for ac to dc current...  but u could add another battery in parrallel with original and if you ahve enough output from ur alternator u won't expierence dimming lights and what not...  S.O.B custsoms.. South Omaha, Nebraska