OK,, DO a search on Amazon for some of the Dometic models, you can pick up some of their NEW Older model around half price, I bought 2 last year or the year before and powerwise I think they are the best thing since sliced bread,
Look for the CDF/CF-18, CDF/CF-21, CDF/CF-26, CDF/CF-31, CDF/CF-36,,, These are mainly 12/24v models, I bought a $10 AC to DC cheap 10A converter so I could use it indoors, I love my little CDF-18L it will use between 4 and 8 Amps per 24 hours and it goes all the way down to -18*c/0*f, Truth is I have seen it go down to -21.1*c / -6*f, It has just a rotary control and Hi and Low Battery protection Cut Off, Awesome little fridge.
These model numbers will be CDF-18 or CF-18 depending what country a person lives for each model. Ok
Have a search for any of those and let me know what you come up with,