How much does getting food from the fridge cost?

softdown
softdown Solar Expert Posts: 3,925 ✭✭✭✭
edited September 2019 in Off Grid Solar & Battery Systems #1
So I woke up early to 50.1 volts. Not bad. Got a glass of milk and turned on the router/tv/laptop power circuit.
Then the fridge compressor turned on and ran for much longer than I expected. Voltage dropped to 49.7 before the fridge was satiated.
Voltage bounced back up 49.9 with the laptop battery recharged and a game of Monopoly finished. 

Which left me wondering  - What does a glass of cold milk really cost in battery wear and tear?  When the panels are not producing energy of course...
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • mvas
    mvas Registered Users Posts: 395 ✭✭✭
    #2
    How long did you leave the door open?

    A quick open & close of the door?
    Then the cooling cycle should not have been that much longer than normal,
    because the "heat of capacity" of air is very low.
    After one cycle, it should be back to normal

    Did you hold the door open long enough to warm up the food?
    Now the compressor has way more cooling to do.
    It may take two longer cycles, or more.

    The longer the door is open, the more the compressor will run ...
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  • 706jim
    706jim Solar Expert Posts: 522 ✭✭✭✭
    #3
    And possibly your fridge started its defrost cycle after you opened the door. Takes more power for a while when this happens.
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #4
    The door is opened twice to get milk. Maybe for 2-4 seconds each time - wild guess there. It is likely that it coincided with a cycle that was due. I'd guess the fridge runs less than 10% of the time - but sometimes it runs for awhile. I think perceptions tend to be exaggerated upon initial wakening? 

    Been record breaking hot lately. The heat in the sunroom creeps a bit and the fridge runs a lot more when it is hot and sunny. The huge freezer could also have been running. 

    The forklift battery is doing OK now that panels are actually charging it. I expect to run the freezer from two 180 watt panels starting ~October. Technically - they are 175 since I "jumped the gun" buying my solar equipment. Builders have to be optimistic I think. But in this alpine desert at almost 8000' - I'm sure they produce more than most 250 watt panels. The valley offers great water and abundant sunshine and terrific distant scenery. Other than that? Eh. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,634 admin
    #5
    Softdown,

    I may have missed the post--What did you "fix" to get your system charging/operating properly again?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #6
    BB. said:
    Softdown,

    I may have missed the post--What did you "fix" to get your system charging/operating properly again?

    -Bill
    This is referring to the auxiliary 24 volt system. The BP panels produced measurable voltage but failed to power the charge controller. The extra couple Grape Solar panels have revived the forklift battery to normal parameters. I figure that cycling it may be beneficial but I want a power outage alarm so I don't lose a freezer full of food. Thanks for reminding me about the alarm.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • LowOnCash
    LowOnCash Registered Users Posts: 5 ✭✭
    #7
    softdown said:
    So I woke up early to 50.1 volts. Not bad. Got a glass of milk and turned on the router/tv/laptop power circuit.
    Then the fridge compressor turned on and ran for much longer than I expected. Voltage dropped to 49.7 before the fridge was satiated.
    Voltage bounced back up 49.9 with the laptop battery recharged and a game of Monopoly finished. 

    Which left me wondering  - What does a glass of cold milk really cost in battery wear and tear?  When the panels are not producing energy of course...
    Lol it has to cost something since as soon as you open the door even for a seconds the cold air pours down from the refrigerator.

    Mike
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  • PNW_Steve
    PNW_Steve Registered Users Posts: 79 ✭✭
    #8
    A few years ago I read a study comparing upright freezers with chest freezers. 

    They found that opereng the door briefly,  on a full freezer had relatively little impact on power consumption. Adding room temperature food to the freezer did make a significant difference. 

    They also found that, under identical conditions, chest freezers a very slightly better efficiency than an upright. Not enough that it would be noticed in a typical application. 

    On a similar line.  I have been shopping for a refrigerator for off grid. I am looking for something around 10cu.ft. and have been looking at Energy Star ratings to compare relative power consumption. The best I have found so far has an estimated power consumption of 328kwh a year. 

    Has anyone here found one with a lower energy star rating? 
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  • 706jim
    706jim Solar Expert Posts: 522 ✭✭✭✭
    #9
    I have an Insignia (Best Buy brand) 11.5 cubic foot fridge rated at 311Kwh/year. A slightly shallower version with the same compressor is 297Kwh/year at 9.9 cubic feet. And three months on a Killawatt meter registered slightly less than this advertised amount. I've seen this model advertised for as little as $400 CDN so should be that much cheaper in the US. Hope this helps.
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #10
    LG  has a 450l  inverter model  uses 299 kw per year.that's 15 cubic foot .  Had one for 2 years now , its great .
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #11
    petertearai said:
    LG  has a 450l  inverter model  uses 299 kw per year.that's 15 cubic foot .  Had one for 2 years now , its great .
    Good numbers for a fridge of that size. Cost? Amazon doesn't seem to list it. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    edited September 2019 #12
    Crazy -seems to only be available in Australia from what I see.  Pretty sure of that. Same with the 454L. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #13
    Im in the little islands a bit south east of Australia. Think it was around $1200  on special .  
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #14
    https://www.lg.com/nz/fridges/lg-GB-450UPLX-450l-energy-efficient-fridge 
    I see it is discontinued ,  shame . 
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #15
    petertearai said:
    https://www.lg.com/nz/fridges/lg-GB-450UPLX-450l-energy-efficient-fridge 
    I see it is discontinued ,  shame . 
    The ratings I seen were very, very good. Wonder what the story is. Sometimes I think we intentionally waste a lot of energy. White roof shingles have been a special order for a long time. They used to be standard.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • papab
    papab Registered Users Posts: 67 ✭✭
    #16
    LG got slapped for lying about there energy ratings a while back
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #17
    papab said:
    LG got slapped for lying about there energy ratings a while back
    I bought an LG 55" years ago and remember their tv's claiming to be far more energy efficient than the rest. Wondered how they did it - well they lied. Doesn't mean they make bad products though. They seem to do alright as a rule. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    #18
    I've recently  got the LG 21.8 French Door unit (LFDS22520S) USA version.  Love it.  Crazy low consumption. 587 kWh /year and at my .09 for grid power,  it will cost about $53 a year to operate. 


    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #19
    MrM1 said:
    I've recently  got the LG 21.8 French Door unit (LFDS22520S) USA version.  Love it.  Crazy low consumption. 587 kWh /year and at my .09 for grid power,  it will cost about $53 a year to operate. 


    That may be efficient for a fridge of that size and build. But I think most off gridders shoot for closer to 400 kWh/year. You got a big fancy fridge I think. I have one - in the city with grid power. I don't sweat leaving the freezer door open while stacking milk so it can pre-freeze my milk before the trip to the boondocks. 

    $50 is pocket change compared to off grid battery strings. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    edited October 2019 #20
    For me,  even off grid,  the difference of 0.5 kWh per day would not be a huge deal breaker.
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #21
    Well it might be for me unless the fridge was quite spacious. I grew up wanting a few things including a big fridge and freedom. Can't complain about my Samsung though - it might be 16.9ish going from old memories - which are surely off. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #22
    LatinaSound said:
    Maybe it started its defrost cycle after you opened the door and this can consume more power. 
    I read that it has two small 300 watt compressors. One for the fridge, one for the freezer. So they stay on much longer than a single large compressor. Still seems to drop system voltage from ex: 50.8 to 50.6 when running. The voltage bounces back when the compressor shuts down of course. 

    It did seem to stay on for an unusually long period that morning though. It does seem to have defrost as I do not find frost on my frozen food. Seems to be a good fridge overall. It is Energy Star rated though not as good as several current offerings. Thinking it was made around 2008? Sat unused until ~2015 when I paid ~$400 for it. It was an $800 fridge in 2008. 

    Has a plastic milk and container holder that is prone to cracking though. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Wyantee
    Wyantee Registered Users Posts: 1 ✭
    edited December 2023 #23
    It's an interesting question you've got there! The cost of getting food from the fridge can vary depending on factors like your solar setup and the energy efficiency of your appliances. When the fridge compressor kicks in, it does draw a significant amount of power.
    If you're curious about the energy consumption, you might want to consider checking out products like barley powder. While it may not directly answer your question, incorporating energy-boosting supplements like this into your diet can help you stay energized while managing your power usage.

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  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    edited December 2023 #24
    Wyantee said:
    It's an interesting question you've got there! The cost of getting food from the fridge can vary depending on factors like your solar setup and the energy efficiency of your appliances. When the fridge compressor kicks in, it does draw a significant amount of power.

    It is interesting but the thread is nearly 4.5 years old. Truth be told there is very little energy invested in the air within a fridge. Lots of energy invested in the contents of it though.
    Welcome aboard!
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  • Graham Parkinson
    Graham Parkinson Registered Users Posts: 175 ✭✭✭
    #25
    Our LG 19 cu ft inverter french door fridge (bottom freezer with ice maker and cold water dispenser in door) use 365 kWhr/yr off grid. 

    No compressor startup surge either and it doesn't seem to care if power goes off and on throughout the day, just picks up gracefully and continues.  Makes a lot of ice - we are very happy with it and have had it for about 4 yrs now.

    Offgrid in cloudy PNW

    Full Schneider system with 18 REC 420W panels, 100A-600V controller, XWPro, Insight Home, six Discover AES Rackmount 5kW batteries, Slimline enclosure, Lynk II, AGS, H650,  H2200, H3000 (On Victron AutoTrans with Gen Line 2 wire AGS on AC1), Kubota 4500, Onan 7500 (on second AGS and AC2).

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  • JRHill
    JRHill Registered Users Posts: 372 ✭✭✭✭
    #26
    We have 2 Maytag chest freezers (mid sized) and a two year old Samsung 21.1, all energy star rated. I couldn't be happier with their lack of power draw. It brings a smile after having any of them plugged into a kill-a-watt for a week and doing some division. For us, even in the summer with temps in the 100s and no A/C, there isn't much change. But at time of the year we don't pay much attention to power demands. It's this time of the year right now that efficiency is so very much needed.
    Off Grid. Two systems: 1) 2925w panels, OB VFXR3648, FM80, FNDC, Victron BMV-712, Mate3s, 240 xformer, four SimpliPHI 3.8; 2) 780w, Morningstar 30a, Grundfos switch, controller and AC/DC pump, 8 T105. Honda EU7000is w/AGS. Champion 3100. HF 4550, Miller Bobcat.
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