12 Volt Refrigerator
12 Volt Fridges – 12V Cool Boxes
In general, there are two main varieties of 12 Volt refrigerators:
Type 1: The cheaper, portable thermoelectric 12V cool boxes: you can get them for as little as $30 and they rarely cost much above $100-200
Type 2: The more expensive and energy efficient compressor based 12 volt fridges, either portable or stationary units. They normally cost upward of $500, some larger fridge freezer combos can cost as much as $3000!
The type 1 units are intended for occasional use when going camping, fishing, in the car, truck, boat, etc. They are not very efficient. Most of them can only cool their interior to about 30 deg F below ambient temperature. They are mostly made of plastic, their walls have thin insulation, their door seals (if any) leave much to be desired…
But they do have two big pros on their side: they are cheap and they are simple with the only moving part being the fan. As mentioned, they are intended for casual use and they can keep your food and beverages (yes, even beer) reasonably cool.
The Type 2 units are intended to be used where power is scarce – for instance in a remote cabin, where the electricity is generated by solar power only. They have a very efficient compressor, driven by an efficient brushless DC motor (most of them use compressors made by Danfoss: BD35F or BD50F), very thick insulation (four inches thick walls are nothing special) and very good, airtight door seals. Some of them are standard, upright refrigerators and the others are chest type. Some even have freezer compartments on top – just like standard refrigerators. Freezer only units or freezer chests are also available.
Their biggest plus is small energy consumption, biggest minus is high price ($1000+ for a relatively small 6 cu ft unit).
But in case of being powered by the sun alone, their higher price compared to cheap inefficient type 1 coolers is quickly offset and more than compensated by lower price of the smaller solar panels and batteries needed to power them.