hk300

I would like to leave my DCF813 impact wrench in the car for emergency use but I would like to keep my battery at home for my other tools. I hooked up the DCF813 to 12V from the cigarette lighter but it didn't work, only the LED lit up briefly and the motor didn't move at all. I notice the battery connector has two more contacts which I suppose is for voltage or temperature sensing. So my question is what else could I do to make it run on car supply?