Originally Posted by 86Scotty
These older ammonia fridges seem to work best on propane, decent on AC, and only marginally on DC. They are very efficient on propane so I would focus on that if you can. Good luck.
I'm not sure if this is why they don't work well on DC, but propane (absorption) refrigerators take a huge amount of electricity to run (on either AC or DC). Of course, on AC, you're usually plugged in so there is plenty to go around; but on DC they are formidable. I don't remember specifics, but if a small compressor style refrigerator would take something like 4 amps to run on DC, a propane (3-way) might take 18 amps or something like that. Not hard to imagine that not going well over a period of time on batteries
I suspect most DC use is while driving.
But like you said, efficient on propane.
But these days if a reasonable amount of solar is an option, I'd tend to opt for a compressor unit. 'Course you have the propane one, so it's natural to try to get it working.