Anybody tried a timer that turns fridge off a couple AM hours on a regular basis?

softdownsoftdown Solar Expert Posts: 3,618 ✭✭✭✭
I suspect my fridge may have an internal timer that does mtce like defrosting in the AM hours. Seems like it is almost always on for a very prolonged period somewhere between 4am and 7am.

That is also the time that may be most deleterious to the batteries. At their weakest point.
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

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    edited June 2020 #2
    Softdown,

    I have tried it with a freezer (I have Time of Day utility rate plan--Turn off during peak afternoon rates). I stopped doing it--Just did not seem to be worth it (no obvious effects on GT Inverter based billing) and worried about higher than desired freezer temperatures and food "loss of quality".

    http://www.appliance411.com/faq/howdefrostworks.shtml

    Good article on the general defrost/frost free circuits.

    My "cheap" refrigerators use a mechanical timer (not sure if 12 hour or 24 hour timing).

    A former poster here tried disabling the defrost timer/heater and found that after ~24 hours, the fridge frosted up and began to use more energy.

    Some refrigerators may use an electronic defrost timer--And if you interrupt AC power, it has been reported that they enter immediately into a defrost cycle (may be what you want, or not...).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • softdownsoftdown Solar Expert Posts: 3,618 ✭✭✭✭
    Good info BB. I'm pretty sure a few posters have tried it. We'll see if any post up.

    I suspect that turning off for two hours at a time would be safe enough. I feel aggravation when waking up and listening to the fridge cycling - again - during those hours. I don't sleep nearly as soundly as I used to. The fridge isn't what I would call loud.
    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
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    See if you can find the defrost timer for your fridge. My mechanical timer has a short shaft with a "one way turn" ramp on it. Give it a 1/2 turn and see how much it changes the defrost timing. (on mine, you can here the contacts "click" when you turn and the timer goes into defrost).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Marc KurthMarc Kurth Solar Expert Posts: 964 ✭✭✭✭

    BB. said:
    See if you can find the defrost timer for your fridge. My mechanical timer has a short shaft with a "one way turn" ramp on it. Give it a 1/2 turn and see how much it changes the defrost timing. (on mine, you can here the contacts "click" when you turn and the timer goes into defrost).

    -Bill

    I was thinking the same thing, but didn't post because I was wondering if there is a mechanical timer anymore! They used to always be behind the grille or kick-plate at floor level. I am very much against artificially holding the compressor off while hoping for acceptable temperatures. Yes, food safety - but also longevity. I have two chest freezers that run at -10F to -18F for a reason.
    The studies that I have read, show that many foods have a virtually unlimited "useable lifespan" when vacuum sealed and always held below about 0F. I tested this a little bit with some 3+ year-old pork ribs that I intentionally left in there to test later. I was betting that my dog was going to get them, but they were great after grilling. Again, in a sealed vacuum type bag and held at -10F to -18F continuously.
    I always have more questions than answers. That's the nature of life.
  • stillchillinstillchillin Registered Users Posts: 52 ✭✭✭
    I believe you will find that your mechanical timers for at least the last 30 years or longer only turn when the compressor is cycled on. So after 8 hrs of run time have been logged the timer will begin the defrost cycle, the defrost heater will be on until a thermostat attached to the evaporator coil interrupts power to the heater, the timer will still keep the refrigerator off until it goes through its preset cycle 20-30 minutes. You can look at the wiring diagram to see if the compressor and timer are energized when the thermostat calls for cooling or if the timer is always energized. Cycling the frig off for energy savings is not worth the effort in my opinion. newer models do have electronics that do this job with coil mounted thermistors to determine the defrost cycles. Hope I made this clear enough to understand.
    18- 235 W Kyocera panel, 12- 4-KS-25PS Rolls 1350 Ah, Magnum MS4448PAE, ME RC50, ME AGS, Outback FM 80, Generac 8KW LP generator, 6.5 Honda Portable generator
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    I tried a timer on manual defrost freezer a couple winters ago, shutting down at midnight, back on at 9am.  Trying to shift some load off the batteries, but had better luck increasing the Absorb time !
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
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  • softdownsoftdown Solar Expert Posts: 3,618 ✭✭✭✭
    So far this sounds beyond me - tampering with the fridge settings could backfire. Did not come with a manual.
    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
  • solar_davesolar_dave Solar Expert Posts: 2,392 ✭✭✭✭
    I was thinking the same thing, but didn't post because I was wondering if there is a mechanical timer anymore! They used to always be behind the grille or kick-plate at floor level. I am very much against artificially holding the compressor off while hoping for acceptable temperatures. Yes, food safety - but also longevity. I have two chest freezers that run at -10F to -18F for a reason.
    The studies that I have read, show that many foods have a virtually unlimited "useable lifespan" when vacuum sealed and always held below about 0F. I tested this a little bit with some 3+ year-old pork ribs that I intentionally left in there to test later. I was betting that my dog was going to get them, but they were great after grilling. Again, in a sealed vacuum type bag and held at -10F to -18F continuously.
    I am for the -10 deep freeze (wish mine would go lower) and the vacuum sealers. Two years no problem with most foods.  When the sweet corm on the cob is around cheap (like 8 for a buck) we get a couple bucks worth and blanch them then a pad of butter and a bit of sea salt.  Just pull them out and drop the bag and all into boiling water for a bit and yum in January.  You can even look around for deals on bags, we usually buy a couple boxes a year.
  • solar_davesolar_dave Solar Expert Posts: 2,392 ✭✭✭✭

    Softdown I just don't think it's worth the recover run it would take on the fridge, they seen to just use about the same all the time. I know it's tough off grid.
  • Marc KurthMarc Kurth Solar Expert Posts: 964 ✭✭✭✭
    edited June 2020 #11
    solar_dave said:
    I was thinking the same thing, but didn't post because I was wondering if there is a mechanical timer anymore! They used to always be behind the grille or kick-plate at floor level. I am very much against artificially holding the compressor off while hoping for acceptable temperatures. Yes, food safety - but also longevity. I have two chest freezers that run at -10F to -18F for a reason.
    The studies that I have read, show that many foods have a virtually unlimited "useable lifespan" when vacuum sealed and always held below about 0F. I tested this a little bit with some 3+ year-old pork ribs that I intentionally left in there to test later. I was betting that my dog was going to get them, but they were great after grilling. Again, in a sealed vacuum type bag and held at -10F to -18F continuously.
    I am for the -10 deep freeze (wish mine would go lower) and the vacuum sealers. Two years no problem with most foods.  When the sweet corm on the cob is around cheap (like 8 for a buck) we get a couple bucks worth and blanch them then a pad of butter and a bit of sea salt.  Just pull them out and drop the bag and all into boiling water for a bit and yum in January.  You can even look around for deals on bags, we usually buy a couple boxes a year.

    Yes!  I too buy foods in bulk/in season/on sale to stock up. Peas, spinach, squash, green beans and broccoli all do very well over the long haul. Plus, I do a lot of Sous Vide cooking so that I can get accurate cooking temps with large cuts of meat like Tri-tip and Briskets in the 10-25 lb. range, then seal in smaller portions in the freezer. I live in ranch-country, so trusted sources of beef and chicken are big with me.
    I always have more questions than answers. That's the nature of life.
  • softdownsoftdown Solar Expert Posts: 3,618 ✭✭✭✭
    I'm talking about an approx. two hour period with the fridge turned off. The "recovery" would likely mean ~ 10-15 minutes of extra run time by my very rough guesstimation. The attraction is that the period would, at least partially, be powered by solar rather than batteries.

    I'm not keen on messing with fridge defrost settings. But I still may try the timer idea.

    BTW - found I still had a small freezer hooked up to the main system to avoid disconnecting power while cleaning. 6AM power readings have been 50.4 and 50.3 volts since fixing that. Kind of obsessed with my AM power readings. If I could avg. 50.4 volts, or better, that should give me another year, or more, of valuable battery life.
    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
  • wellbuiltwellbuilt Solar Expert Posts: 763 ✭✭✭✭
    I don’t have a timer on my frig but I make a bathroom run at 430 am and I will turn off my frig  , then turn it back on at 700 or 8 when I get up 
     every thing stays frozen and cold  this time of year I’m getting a few 100 Watts by 7/8am 
     in the winter I start the generator first 
     I don’t think it saves a lot of power . 
     I don’t store food  long term 


    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
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