No knowledge about the car charger, but I believe my inverter, only about $99 or so at Frys, is just as fast as household ac. I can also charge several devices at a time, camera battery, iPhone, Surface, camping air mattress air pump, because each device takes a very small amount of current, and I don't have to buy and store several devices. I just use the ac charger that came with the device. The inverter I have is about the size of two paperback books one on top of the other, and it stays out of sight in the console of my Taurus until I need it. Good investment of a hundred dollar bill.