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I went to the 5er yesterday and turned all the AC loads on. My base AC consumption went from 13W with just the fridge on (compressor not running) to 53W. I think that is due to the 2 TV's that are never really off, the Roku 5.1 sound system (5 speakers always on) and maybe a bit from the microwave display. This means that my 5er, just sitting there doing not much of anything, is drawing 40W on the AC side. DC side is another 60W. So 100W at idle. 2400 W/h a day. That's a lot. My 10,700Wh of batteries would be completely dead in 4 1/2 days.
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2015 Chevy 2500HD 6.0 4x4 CC SB
2021 Salem Hemisphere 290RL > GenY
1600W Solar > 10,700Wh LiFePO4 > Victron MultiPlus II
... I guess I wouldn't be surprised if fewer/longer cycles were slightly more energy efficient due to startup transients and reaching steady state performance.
Bingo. The heat loss will be the same, but the energy consumed will not be the same as the longer cycles will be the difference. More run time and less equalizing.
There is some difference in the air exchanged when the door is open. That might be a wash with less air with a full fridge, but more condensation if it's humid.
Don't know what brand and model of fridge you have in your RV as you failed to post that information.
I did a power usage study on my Samsung RF197 a few months after having it installed. We were full-time RVer's at the time so the fridge was generally full all of the time.
I used a Kill-O-Watt P2 to do the study and I did this on two different months to get a comparison.
I determined that the RF-197 which has a normal type of compressor uses 1800 Kilowatts of power everyday. That equates to 160AH of Battery usage per day just for the fridge.
The newer Samsung RF18 now comes with a DIC aka digital inverter compressor which runs all the time either on idle or ramped up when cooling. I don't own one so I have no idea how that compressor affects the kilowatts used per day.
Copied from a Samsung Web Page about Digital Inverter Compressors. "The Digital Inverter Compressor enables the new Samsung French door refrigerator to maintain a more consistent temperature and use electricity more efficiently. The resulting Energy Star rating qualification means you save 25% more energy than the minimum DOE standard for fridges in its class. The compressor also helps preserve your home environment, running more quietly than conventional compressors."
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2006 42 FT Monaco Dynasty Countess III (Codymobile)
2002 40 FT Monaco Windsor PBT/Owned for 18+ Years
1992 36 FT Airstream Landyacht (bought 2001)
There is a lot of variation, depending on the design of the reefer. Most big, energy star units are actually powered by a built in inverter running the compressor at variable speed. As such they actually run all the time and don't cycle like grandpa's reefer used to. My unit is a 22 cuft Frigidaire and it runs an average of 96 watts...all the time. Cycle is a little complicated with peak load of 600 watts during the 15 minute defrost cycle. After that it draws around 150 watts on compressor high, catching up from the defrost cycle and then drops to 50 watts for the rest of the time. This then repeats about every 8 hours. This turns out to be around 110 AH per 24 hour period. I can go a while on my 4 FLA battery bank.
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Scott Brownstein
Palm Island, Florida
2015 Georgetown 335DS
I finally got around to setting up my Victron system so I can do remote monitoring. Got some data on the 18 cu ft residential fridge. It took four hours of compressor time for initial cool down. Averaged 115W for that four hours. Then it went to maintenance and seems to have a 50% duty cycle. 15-30 minutes on followed by 15-30 minutes off. Average 90W while compressor was on and 0W when it wasn't. So that is 45Wh. For my 12.8V system, that is 3.5Ah. This kindof irritates me because the fridge/freezer were never opened the whole time. Seems like a lot of Wh for a fridge that was never opened. Glad I have a lot of batteries and solar.
This is AC not DC? Or does the residential fridge have DC option? I would of thought with inverter and AC it would have a larger AH draw.
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2010 Cameo F34CK3, 500ah GBS LFP, 1280w solar, Magnum PT100 SCC & 3012 hybrid inverter/ charger, Installed 4/2016 been on 24/7/365, daily 35-45% DOD 3,046+ partial daily cycles.
Turns out these residential fridges do defrost cycles, too. Four hours long.
That is a pretty long defrost cycle, although but then it is only a 125 watt heater. On my Energy Star 22 cu/ft, defrost is only 15 minutes...but it is 600 watts!
Still, for an average of 95 watts or so it is worth it for such a big unit.
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Scott Brownstein
Palm Island, Florida
2015 Georgetown 335DS
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