Can I use a car battery for car audio?
Unless you want to listen to music with your engine off, adding a dedicated car audio battery isn’t going to do you any good—and it may actually hurt. That might seem counterintuitive, but the reasoning is simple. The battery in your car is there to serve one purpose: to provide enough amperage to start the engine.
Do I need a second battery for car audio?
Secondary batteries are necessary when running the car stereo for extended periods of time. They are also a necessary addition for systems with such a large power draw, and systems where the electrical needs exceed the output of the alternator.