A:Answer Only the back USB-C port is used for charging, and as long as you have 5vdc you are OK. You will in no way charge as quickly as from the supplied HP charger, but it will charge as long as your car is on. Some newer 2014 plus vehicles have off charing, but I would not leave my laptop plugged in if away from the car for any serious amount of time. Since your laptop will not jump your cars battery.