2-Usual fridges work with the AC grid, and have a strong inrush current at start. If you want them to be run from an inverter, the inverter power will need to be oversized, could be by a 10 factor if not more.
Curious what you mean by a factor of 10? Do you mean that if the surge of a fridge startup is 900W, then one would need a 9000W inverter? That doesn't make sense, as our 800W surge works fine (until the battery gets low/voltage sag) on a 2000W inverter.
We have a 120V AC fridge "Avanti" brand that was highly raved about on RV solar forums. It draws 800W for 1-2 seconds when the compressor starts up, then instantly drops down to usually about 65-70W. I've seen it at 75W a few times and once as high as 90W, but usually around 65-70W.
Now when the fridge is first plugged in, it pulls 500-600W for about 5-8 seconds, then down to 0W, then in 2-5 minutes will do the normal cycle of 800W for 2 seconds, then 65-70W after that.
We have it plugged into a 2000W inverter. Usually no problems, but we have a gremlin either in our battery setup or cabling. I hope I now have the cabling fixed, I'll know in a few days when my wife returns to town with the trailer. And I think our battery gremlin is 1) not producing enough AH during daylight hours especially when traveling (flat roof mounted panels at 48-degrees north) and 2) not charging at high enough C-rate for a SLA battery bank, except when the AC charger is plugged in, which requires the generator (noise).
Now what I don't like about this fridge is there are zero fans in it. Using an infrared thermometer, with the fridge temp setting at 4 (midway), I will get 15-30F in the very back of the fridge, depending on where it is in it's cycle of cool/defrost. The items in the door will be about 38-40F and items in the shelves, even pushed back to the coldest back wall, will show 41-52F. Not a concern for me for camping for a few days or a week, but my food-sciences trained wife is growing grey hairs over this! I put a battery powered desk fan inside and it seems to help...a bit.
Since our system seems to be underpaneled and under-battery'd, I've thought about simply turning the inverter off overnight. Maybe crank the fridge temp up to 6 or 7 (the freezer got down to -20F when I turned it up to 7) in the latter part of the day to get it good and cold but while there's still sunlight out and then turn it down 2 hours before sunset and then shut it off 30 minutes before sunset. That's a lot of fussing around just to save some battery juice. We do have a generator, but the noise of it kinda defeats the point of the silence of solar. I doubt my wife would go for this plan, though, because likely the fridge internal temps would be in the 40's or 50's in the morning. This wouldn't fly or be safe in the hot days and nights of summer, but it could work in the shoulder seasons where the ambient temps are 70-80F in daytime and 30-50F at night.
Anyone else try or do this - turning off the fridge/inverter at night to save power?
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