I have a very old 12 volt refrigerator
. Runs off of 12 volt and 110 volt. Has a compressor. When plugged into 110 a relay switches to run compressor off of a fairly large transformer, about size of a large grapefruit. Unplug the unit and the relay switches to 12 volt battery
Only draws about 5 amps when running, runs intermittently rather than continuous so doesn't run down the battery
the way the heating element of an absorption refrigerator
I ran it for several days in my garage mostly off of 110 but also for several hours off of 12 volt. Then took it to a friends cabin and hooked into his solar battery
bank. Ran for about 20 hours and just stopped.
Still runs off of 110 volt, doesn't run off of 12 volt. Compressor is always 12 (or 24 volt running on 12) so thermostat and compressor are both working or it wouldn't work on 110 power.
I'm looking for a couple of answers.
Has anyone any experience with these old style 12 volt compressor refrigerators with an idea of what could cause the 12 volt side to stop working. Just out of the blue. I did find a ground wire that had come unsoldered and was just barely attached. That has been attached now. Still no joy.
What sort of inverter would be required to run this off of AC inverter? I think the motor always draws close to 5 amps with the AC power going through a transformer to convert to 12 volt to run the compressor I was thinking modified sine wave would still work but have seen some stuff about modified sine wave and transformers that makes me unsure.
I am really hoping I can figure out what suddenly failed so that the straight 12 volt power didn't work while the AC to transformer power does still work. If I can't then running off of an inverter is still viable. I think the power draw is much less than a typical home fridge
I'm also unsure of the load the inverter will put on the solar
system. It is a 285 watt PV set up with 4 batteries and running on 12 volt directly the refrigerator
didn't do much to draw the battery voltage down over night. Inverter will up that load some but by how much?
We had ice for a single night at the camp, now we are wanting to make that a permanent feature. :-)