If you are looking for the best 12V portable car heater, you must check out these two. RoadPro Direct Hook-Up Ceramic Heater- This is a direct-wired ceramic heater that instantly starts up heating your car and truck and also defrosts the windshield. It is connected directly to your battery and has 300 Watts of power along with a swivel base. It can also switch from heat to cool settings. Blue--net Universal Car Truck Fan Heater- If you want something to spread heat evenly in your large vehicle, you need this one. It is best for regions that face bone-freezing cold as it defrosts and de-mists the windows for you and, with its 6 ports, keeps you warm enough to drive comfortably. Compare these two best 12V portable car heaters and choose one for your car.