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  1. #1
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    New guy needs some help



    Hi all
    Im not a refrigeration engineer by any means but really need some advice! I am trying to run a freezer from a battery and inverter set up, but not having any joy gettting it to run.

    Here is the freezer specs
    Voltage 230v
    50Hz
    1.3A
    LRA 9.5 - 9.7

    Battery
    60Ahr

    Inverter
    800w modified sine wave

    It will almost start up but not kick over, i think this is due to the large inductive start up current but not sure what inverter i need or what to do to over come it.

    Please any help would be amazing!!



  2. #2
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    Re: New guy needs some help

    Look for start capacitor that will fit the compressor, it will require a special relay which will disconnect it and kick in the running capacitor.

  3. #3
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    Re: New guy needs some help

    thanks for the reply is the start capacitor on the freezer? Do you know what relay i would need?

  4. #4
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    Re: New guy needs some help

    Quote Originally Posted by deckstar View Post
    thanks for the reply is the start capacitor on the freezer? Do you know what relay i would need?
    It's not that simple unfortunately.

    You need to know what make and model the compressor is.
    dependent on the type of compressor you might or might not
    be able to use a different starter to start the thing.

    Your 800 watt inverter will only deliver about 3.5 amps, your
    comp will pull 9 amp for a fraction of a second to a second. So
    you either need a bigger inverter or you need to drop the
    start current to 3 amp.

    Post the details of the comp and maybe we can advise on
    if it will start with a capacitor or not?

    Regards

    Rob

    .
    Last edited by Rob White; 06-04-2013 at 09:27 PM.
    .. ... -. .----. - / -- --- .-. ... . / -.-. --- -.. . / --. --- --- -..

  5. #5
    Join Date
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    Re: New guy needs some help

    Yes, your inverter is too small for the job + the battery won't last long enough to do any reasonable amount of work.
    To the optimist, the glass is half full. To the pessimist, the glass is half empty.

  6. #6
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    Re: New guy needs some help

    thanks for the help so far, the compressor is Embracco EMI 70UER. The battery is quite small but needs to be run on a bike as i have a portable ice cream bike so weight is a factor! What inverter would you reccomend if i was just to uprate the inverter?

  7. #7
    Join Date
    Feb 2007
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    Re: New guy needs some help

    Quote Originally Posted by deckstar View Post
    The battery is quite small but needs to be run on a bike as i have a portable ice cream bike so weight is a factor!

    Additional dynamo(s)?

    The problem you face is the huge starting current you are facing with any compressor.
    As Rob stated above, it will be at least 9 Amp and maybe even more for a fraction of a second when the compressor just start to turn over.
    To be on the safe side you would look at an inverter capable of supplying in the region of 15-20 Amp.

    Another thing you need to be aware of is the battery's capacity. 230V x 1.3 A = 299W. 299W / 12V = 25A. Therefore a 100 AmpHrs leisure battery is likely to only last a couple of hours...

    Tried to use dry ice or liquid nitrogen?


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