You don’t have to install a car stereo into a car to make it work. You just need a power source. In the case of car audio gear, you’ll need a 12-volt battery, like those used in car electrical systems. With the battery and a few simple parts and tools, you’ll have the car stereo powered up and ready to go in no time. Tips Writer Bio

How to Run a Car Stereo Directly Off a Car Battery - 49