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.
Items you will need: Wire cutters/strippers, Two alligator clips, Crimp tool, Battery
Strip 1/2 inch of insulation from the red and yellow wires on your car stereo’s wiring harness. These are the constant and switched power cables.
Twist together the bare ends of the yellow and red wires and slide them into an alligator clip. Crimp the wires into the clip with a crimp tool.