Running fridge on solar panel

Discussion in 'Tech/Mech General' started by ojibway, Jun 6, 2013.

  1. ojibway

    ojibway Funster

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    Hi Funsters,
    our son has a caravan :Rofl1:
    He is going to leave it on site for the summer and wants to know if he can leave the Dometic fridge/freezer running off 2x leisure batteries and an 80watt solar panel. There is an electric hookup but the site doesn't want people leaving appliances running whilst away. The alternative, he reckons, is to run it off gas.
    Personally I think he can run it off solar+batts as it will not be opened whilst away and it will be on hookup on week ends.
    Any advice welcome!
    Mike and Annie
     
  2. chaser

    chaser Funster

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    Hi
    Doubt it they don't run of the leisure battery, normaly they only work on battery when the engine is running on motorhomes , but caravans may be different but even so it won't run for long on battery anyway, why does he need it on
     
  3. GJH

    GJH Funster Life Member

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    An absorption fridge pulls 85w. On a 12v supply that is about 7 amps. The solar panel isn't likely to be putting in more than 4 amps at best. The length of time the two batteries will last depends on their capacity but unlikely to last long enough.
     
  4. cmcardle75

    cmcardle75 Read Only Funster

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    Not a chance. The fridge will require orders of magnitude more power than an 80W solar panel will provide over the course of even a sunny day. You might get away with 10 panels and a very large battery bank, in summer.
     
  5. SomeoneElse

    SomeoneElse Funster

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    The fridge in my autoquest was rated at 120W on 12V so running it 24/7 on a 80W panel is a non-starter.

    A general rule of thumb was that one watt permanently for a year costs £1. I suspect its a bit more but you get the idea. The same fridge was rated at 150W on mains, so let's say £200 for a whole year.

    You need to talk to the site owner as I'm sure he is trying to stop people permanently running 2KW heaters in their awning. That would cost 10 or 15 times as much. Running a "small" fridge doesn't sound unreasonable.

    Gordon
     
  6. ojibway

    ojibway Funster

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    Thanks everyone.
    I thought he might get away with it as a fridge does not "run" constantly. Our little compressor fridge runs off the leisure batteries only, when we are not on hookup (and that most of the time as we use aires mostly) and you hear it kick in every once in a while. It doesn't seem to use much power. We have two large gel batteries.
    Why he needs it running? Well, he's a lad, innit:Wink:
    Mike and Annie
     
  7. pappajohn

    pappajohn Funster Life Member

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    big difference between an absorption fridge and a compressor fridge.

    Absorption fridge runs constantly if 12v is present, ie: engine running.....that's 168amps in a 24 hour period if it draws 7 amps per hour....

    compressor fridge is intermittant and will draw maybe 1/4 to 1/3rd of that in the same time period.
     
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