There is a company named 
Engel that makes a very nice high effiency line of refrigerators and freezers  (Some are Refrigerators only, others it depends on how far you turn the knob).
Mine is 9 years old and still going strong.. Draws on the order of 35-40 watts running, less when not running.   Only thing I have done to it is the occasional defrost and last winter I blew some dust out of it (not that it was complaining, but I felt the need) 
Can run on 12 volts or 120 volts
I can sit on it (I am over 300 pounds) some models might be the wrong size for that. 
Works very well in my opinion. 
They describe the compressor as a "Sling Motor" it compets with the Danfoss units.
Norcold and Dometic also make competiting prouducts now (did not then)   I really like this thing.   Beats the BTU's off the solid state "Koolatron" type coolers.