A quality 12v fridge freezer that is intended for auto or off-road fridge will be a compression technology fridge. I will briefly discuss the benefits of a compression fridge over the alternative absorption technology type of refrigerator when your intended application is usage as a car fridge.
A compression fridge is designed specifically to be powered by electricity. Unlike absorption fridges which can be powered off LPG, a compression fridge uses a more efficient and expensive technology which allows them to cool using less energy. This allows them to be run from a 12v DC car battery for an extended period of time before impairing your ability to start the vehicle.
Compression fridges also cool better. Your average absorption fridge comes with caveats such as ‘able to cool so-and-so degrees below ambient temperature’. A compression fridge will cool as much as you need. They can even function as freezers. This speaks volumes to their cooling ability.
A compression fridge freezer will operate when it is not on a level surface. An absorption fridge needs to be almost perfectly leveled if it is to work correctly. For a fridge being used in a vehicle, the ability to run smoothly when going over bumps, and driving up or down hills, is essential.
The one drawback of a compression fridge is that they generally cost more than an absorption fridge. If you see a 12v fridge that looks like a bargain, beware! It is probably using absorption technology rather than compression. If it is relatively expensive, and has the capacity to freeze, you can probably safely assume it is a true compression model.
Be sure that if you are buying a 12v refrigerator for your vehicle that you purchase a compression fridge. The extra expense is well worth the advantages the compression models have over the competing absorption technology.