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A refrigerator on a $45 HF inverter?

Discussion in 'Home Power and Microgeneration' started by Toller, Aug 27, 2005.

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  1. Toller

    Toller Guest

    Harbor Freight has a 800w, 1800w surge, inverter on sale for $45. At that
    price I would like to pick one up as backup for my generator, if it will
    safely run my refrigerator.
    My frige is a medium quality 2 year old Kenmore. There are no digital
    displays, or anything like that. (I am not sure how the water filter
    indicator knows to go red in 6 months...) It draws 13a for a second or two
    starting, then drops to 1.5a.
    I am concerned that:
    1) the claimed 1800w surge is fantasy
    2) that the modified sine wave will damage the motor

    $45 is a great price for a backup I hope to never use, but not if it will
    trash a $1000 refigerator.
    What do you think?

    My $100 shopvac will shut off if the motor gets too hot; do $1000
    refrigerators do that?
  2. Vaughn

    Vaughn Guest

    My 1000 watt square wave inverter and my 'frig do not like each other.
    Sometimes it will start and sometimes not. I suspect a larger start cap on the
    compressor would fix, or reduce, that problem. But why?

    How big is your battery anyhow? Figure 19 amps drain (@ 80% efficiency)
    from the battery. If you have an 80 amp-hour battery and you confine yourself
    to a safe DOD, then you are looking at perhaps 3 hours of operation. I looked
    at those numbers and decided that I don't really care to operate my 'frig off of
    my battery bank. Most refrigerators can go 24 hours without power before bad
    things start happening. You should be able to run your generator during
    daylight hours only and still keep things cool enough for food safety.

  3. Toller

    Toller Guest

    I am concerned about the generator breaking; if I can get backup for $45...
    I had in mind letting it go for 12 hours, running it for an hours to cool
    off again, letting it go for 12 hours...
  4. Vaughn

    Vaughn Guest

    For the full 800 watts you are correct (based on 100% efficiency).
    However, the OP's refrigerator does not draw 800 watts. 1.5 amps X 120 Volts =
    180 Watts

  5. Guest

    Rather than this why not get a propane fridge?

    Serious question. Trying to learn something
  6. Steve Spence

    Steve Spence Guest

  7. Guest


    But why do you prefer the electric over propane?

  8. Steve Spence

    Steve Spence Guest

    Sears 18 cu. ft. fridge/freezer $410

    AC Delco 2500 watt Inverter (BJ's Wholesale) $269

    Walmart 115ah Deep cycle type 27 batteries (qty 6) $360

    schumacher 40 amp smart charger, walmart $100

    later, add a solar panel and a charge controller, and you are on your
    way to being off-grid.

    more on this type of setup in the next issue of ESSN magazine (free) in
    4 days (always published the first of the month) at

    Steve Spence
    Dir., Green Trust,
    Contributing Editor,
  9. Steve Spence

    Steve Spence Guest

    Propane is the only solution where electricity is in short supply.

    The electric one has an interior light, keeps a more stable temperature,
    and I can make my own electric, I can't make more propane. Propane
    works great in power outages for storms.

    It all depends on your situation.

    Steve Spence
    Dir., Green Trust,
    Contributing Editor,
  10. Guest

    How is it a dead loss?

    Can you explain to someone who is trying to learn?

    Thanks so much!
  11. Toller

    Toller Guest

    I have a tiny propane refigerator at my dock to keep drinks in. Because of
    the lake, it is very mild down there, yet I go through 20 pounds of propane
    in a month. The electricity to run one the same size would be darn near
    Also, it cost $500. An electric would be $70. And, I doubt the propane
    fridge will last nearly as long. (though I am hoping to be surprised.)
    Still, it is amazing that you can cool with a flame.
  12. Guest

    Greta example. Thanks!
  13. Steve Spence

    Steve Spence Guest

    not a great example. In an off-grid situation, the equipment to generate
    that electric would out price the propane for a long time. It's all
    decided by if you have the up front capital for enough solar and wind
    generation to keep a fridge going, or if you can only afford a tank of
    propane every once in a while.

    Steve Spence
    Dir., Green Trust,
    Contributing Editor,

    Greta example. Thanks![/QUOTE]
  14. Steve Spence

    Steve Spence Guest

  15. Steve Spence

    Steve Spence Guest

  16. Steve Spence

    Steve Spence Guest

  17. Steve Spence

    Steve Spence Guest

  18. Steve Spence

    Steve Spence Guest

    A typical electric fridge might use 3.9 kWh (13306 btu) / 24 hour
    period, or .24 gallons of propane (21745 btu).

    Propane 91,330 btu/gallon
    Electricity 3,412 btu/kWh

    If I paid $1.66 / gallon for propane I'd pay $0.40 / day, my neighbor
    who pays $0.15 / kWh would pay $0.58 / day.

    Of course, a $8000 pv system might keep this fridge powered for "free" ...

    Steve Spence
    Dir., Green Trust,
    Contributing Editor,
  19. ....
    This is why it's important to measure things. My fridge happens
    to run about 1.5 kWh/day and I always thought it was fairly
    typical. :)

  20. Steve Spence

    Steve Spence Guest

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