If you want more power in your car but don’t want to waste your cars battery, how about installing your own power panels?
This project is all about taking apart the inverter and hook up the internals to the cars battery and by adding some 12 volt cigarette lighter outlets on the other side of the panel. The inverter also came with a USB port you will be able to get some pretty good power out of this thing. You should easily be able to charge other power-hungry devices instead of just your mobile phone.
This is a little harder but it will give you quite a fair bit challenges.