Help with gettin power to car

K I saw in a magazine once that this guy had I'm guessing a battery charger up so that whenever he was at shows his battery wouldn't die from having the car on and playing music, showing his screens off and such. How would be the best way to go about this or is there something specially made for this?

Thanks
Brian

You kinda answered your own question.. I have a battery charger that can jump the car too, but it plugs into an outlet. Was his portable?

yea
it was mounted somewhere and he kept it in the car so that he went to shows and would plug it in and he would have good power the whole time...because unless my car is running my cd player will start to go dead soon...especially whenever I get my subs...how would I do this?

ricochet? do you have a charger that stays on the car 24/7 or do you justplug it up when you need it?

maybe add another battery.

I meant a charger you plug into the wall at home, and connect it to the car battery if you need a jump/charge.

he might just have a converter somewhere that changes 110v AC to 12v DC that he can just hook the power wire from his battery to.