You can do it but it would be very costly, not to mention time consuming. You would have to step-up the voltage of you battery to give the ps2 120v - you would need to make/build a small transfomer. It is much better just to go and get a power inverter and that will save you time and money (electrical parts are expensive). Make sure you get a power inverter that has at a bare minimum 150watt power handling. You can wire the power inverter directly to the battery -- just make sure you have a fuse inline, and you mount the unit inside of the car. Hope this helps!