Do not leave your fridge running on the 12V connection on car battery for more than 2 hours. When you are driving put the fridge on a colder temperature, that can then be raised when you a stop. Use the 220V connection whenever it is possible. If necessary, use ice to keep your fridge cold when you have no electricity source. Make sure that the vents of your refrigerator are well ventilated or this may cause damage to the refrigerator.