The initial cooling process can take anywhere from four to six hours so you will want to turn the fridge on at least a day before you leave for your trip, and let it get to temperature before placing food items in it. Place any food you are planning to bring with you and store in the fridge in your home fridge or freezer first. You will want to place food that is already cold or frozen in the fridge to avoid it having to work harder to cool the items inside.
Do not overpack or stuff the fridge completely full. A fridge needs to have space between food items to allow air to circulate through the inside.
Boost air circulation by purchasing a battery-operated fridge fan and placing it in the front while angling it to blow air upward. The fan can improve circulation and reduce cooling time up to 50%.