Yeah, the refrigerant needs to drain or you’ll run the compressor dry - not good. I like the old-tech, but when I build again, I’m going with something more compatible with photovoltaic power. Something like: http://www.sunfrost.com/
Save your money on the fridge and just get a regular one. If you watch the rebate programs that the utility companies are being forced to implement, you could go with a grid tie photovoltaic system for almost nothing.
I installed a 10kW PV system and aside from my own sweat installing it, it cost me nothing after rebates. It supplies all of my electrical needs, including heating, hot water and air conditioning. My electrical bill in zero and I have a big ol GE, side by side, Arctica fridge.
I think propane is the best bet for refrigeration off the grid