will my solar panels run the Dometic fridge?

Discussion in 'Tech/Mech General' started by Dogeared, Jul 27, 2014.

  1. Dogeared

    Dogeared Funster

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    We have recently added a second battery plus 100w solar panel to the motorhome.

    Will the fridge (once cold) be able to maintain the temperature via the solar panel system.
     
  2. Techno

    Techno Funster Life Member

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    Not really
    To be in with a chance you need enough solar to match the fridge consumption
    My fridge can draw 14 amps my solar can/has produce'd over 21
     
  3. funflair

    funflair Funster Life Member

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    Yes you can BUT certainly not all day, which is essentially the same answer as Tecnhno's not really. You won't have the power to run it all day even if the sun is out so what you need is some way of controlling when the batteries will run the fridge and when to go back to gas, our solar controller (Votronic) does this for us as it has a AES output which switches the AES fridge as long as it is connected to the S+ or D+ with additional diode.

    Is it worth messing about doing it with a relatively small solar array of say less than 200watts? Most likely not, I only did it because the controller I fitted had the feature and I just wanted to see if it worked ours might spend 50% of a sunny day on solar so some gas saving I guess but not a lot in the great scheme of things.
     
  4. JJ

    JJ Funster

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    To keep things straight forward.

    The answer to the OP's question is

    No.



    JJ :cool:
     
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  5. funflair

    funflair Funster Life Member

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    That's one answer, or YES but not for long is another, I prefer to supply the facts as I see them from personal experience.
     
  6. voyagerstan

    voyagerstan Read Only Funster

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    i'd go for no too.(n)(n)(n)STAN
     
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  7. Wissel

    Wissel Read Only Funster

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    No, your solar panels will not keep up with your fridge.

    If you have 200Ah of batteries and abide by the 50% rule you have about 100Ah of usable power, but this depends on your charging system.

    If you have a good smart charger then you can fully charge your batteries. If you have the usual split charge system this will only charge your batteries to 80-85%, so say 170Ah or 70Ah usable.

    If, like in the post above, your fridge uses 14Ah your batteries will be dead in around five hours, maybe a couple more with the solar panel.
     
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  8. Dazzlin

    Dazzlin Funster Life Member

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    I'd go for yes, like funflair but only for a limited time during a sunny day.
    I run ours but only on manual.
    Need to sort out summat like wot techno's got. (Only had battery alarm go off once!)
     
  9. John Laidler

    John Laidler Funster

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    If the wiring in the OP's MH is anything like ours you can't run it from the leisure battery/solar panel even if you wanted to as the fridge is wired only to run on 12v when the engine is running. Of course if you re-jig the wiring you could but why would you want to unless you were trying to flatten the leisure battery in the shortest possible time. This assumes the 'fridge in question is a 3 way one. If it is a compressor 'fridge then yes, you should be able to run it off the leisure battery/solar panel combination for possibly several days especially if the sun is big round and shiny all day.
     
  10. funflair

    funflair Funster Life Member

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    Good point made here, your fridge needs to be wired to run off the leisure batts in the first place.

    Martin
     
  11. John & Joan

    John & Joan Funster

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    VWAlan runs his home fridges from his parked unit in the UK in summer. He has 800w of solar on the roof and very large battery banks. He runs the fridges on an inverter. He also has a domestic fridge freezer in his unit, which is run on solar during the winter touring Spain etc.

    So yes it is possible but not with 100w solar and 200Ah battery.
     
  12. mitzimad

    mitzimad Funster

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    i dont think dometic make a compressor fridge so im assuming this is a three way absorbtion fridge which should only run on 12v whilst driving
    also the 12v side has no thermostat so if you did run it from the leisure battery it wouldnt regulate temperature and therefore be permanently on
     
  13. tonyidle

    tonyidle Funster

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    I suppose my question is: Why would you want to?
     
  14. funflair

    funflair Funster Life Member

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    Why not, if there is sunshine to spare why not run the fridge on it instead of gas, and I would imagine but don't know for sure that the back of the fridge runs cooler one 12 volts than on gas as there is not the heat in the exhaust gas to get away from the condenser 12 volt fans etc, important in hot climate when the sun is at its best. You know it makes sense.
     
  15. Reallyretired

    Reallyretired Funster

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    Simplest, though not the most efficient, is to run it on mains via an inverter, however you really need more than 100w solar, and a cunning way to switch back to gas automatically as otherwise you will forget and flatten your battery.
     
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