Small Dorm Room Fridge Power Use

[John "T" Nordhoff]

I had a pleasant surprise regarding the power required to run an additional small dorm room type 120 VAC Fridge I recently installed in my motorhome. To have room for DRINKS ONLY I recently bought a small Haier 1.7 Cu Ft. fridge from Wally World for $80 bucks for the RV. Sure its small, however you can pack nearly a case of beer/pop/water in it plus the first wife even keeps a small sack of ice in its freezer. So we do a lot of extended dry off grid camping and I wanted to know how much power it consumed to determine if I had enough solar and battery capacity to run it continuously. I currently have only 200 watts of solar panels but am adding an additional 240 watts this spring before we head West. I have Four Golf Cart Batteries in Series/Parallel for 460 Amp Hrs total. My buddy has a plug in Watt Hour Meter so I plugged in the fridge (it was already cooled down) and let it run 24 hours with normal open and close use to get drinks when needed.



The results were:



236 Max Watts (That's when it starts) after start up it draws from 1 down to less then 1/2 amp during a typical four minute run cycle.

0.364 Killowatt Hours of use in 24 hours



364 Watt Hours divided by 12 volts (inverter input from battery bank) = around 30 Amp Hrs of energy to run it 24 hours



Subject, of course, to how many panels you have and the sun and angle etc., if your solar system could pump say 5 amps for 6 hours in a day into your battery bank that would be enough energy (30 Amp Hrs) to run the fridge.



Of course, the inverter is less then 100% efficient and there's other RV energy use such as water pump and vent fans and furnace and LED lighting and computer and cell phone charging and small TV/Radio etc.



Still, it looks like as long as I have decent sunlight for a few hours per day I can easily meet my energy requirements, fridge included, especially after I add more solar panels. I was just surprised at how little energy the small fridge requires and am a HAPPY CAMPER



John T

[Rich Thomas]

Hi John T, Hope your having a good winter season. I like the Idea of the small fridge for drinks, it would take a load off the main unit when camping with kids plus you could probably stick it out side in the shade and save on air conditioning too. I don't have any solar panels but I like your forward thinking and appreciate the info.  

[Lakota Wolf]

I have an haier mini,, 24x24 and a 24 x 36 mini fridge I run 600W of solar thru, and the battery bank can be stressed if you dont have a day with good sunlight. If the power level drops to low, the larger fridge is kicked off line, followed by the smaller one in extreme cases. But so far so good. I would recommend running 600 watts if you have a high demand such as other electronics etc, and like John mention numerous times a GOOD set up of battery banks.

[david craft]

Good discussion...i had a customer in one time. A retired mechanical engineer who built his own solar setup. A big rotator handle on the ceiling and analog meters on the wall for voltage and amp readings. One large panel, 110 watt, 26x62 inches, pitched up to catch direct sun. When rotated to the sun it put out 7 amps. I would imagine if left flat onthe roof you would look at half that output, possibly a little less. However the fridge in the wee hours of the night, when ambient temps are cooler would have less draw presumably. Assuming no midnight foraging...