Fitting A Fridge Relay ?

Discussion in 'Motorhome Chat' started by Yorick, Jul 26, 2014.

  1. Yorick

    Yorick Funster

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    At the moment my Dometic fridge is wired straight to the vehicle battery as per the manual.

    Unfortunately I can be a plonker sometimes and left the fridge on when the engine is stopped resulting in flat battery. The vehicle no starty. Boo !

    So I wanna fit summat inline that will only let the fridge draw from vehicle battery when the engine is running.

    Firstly what do I need ?

    And is it a case of just fitting it to the postive wire from battery to fridge ?


    Please keep answers simple as I am a numpty with leccy :mask:
     
  2. John Laidler

    John Laidler Funster

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    If you have a dashboard cigarette lighter check to see if it only works with the engine running - ours is like this. If it is this would be a better place to take the feed for the fridge from. Alternatively, use it to trigger a relay with the fridge wired to the battery through the relay.
     
  3. Yorick

    Yorick Funster

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    The manual says it must be wired directly to battery.
    What does that mean in simple terms ?:BigGrin:
     
  4. John Laidler

    John Laidler Funster

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    A relay is usually a coil of wire which when energised closes some contacts. Sometimes they also open contacts at the same time but that won't be needed in this case. A typical use of a relay is to use a small current to switch on something taking a higher current.

    So the feed to your fridge would be connected to the relay contacts and the coil energised by a wire coming off somewhere where there is only a voltage when the engine is running.

    The problem is finding a suitable relay and a socket to plug it into. Here is a possible one: http://www.halfords.com/motoring/ga...-supplies/halfords-hef555-relay-12v-40a-4-pin
    If you look at the second image it shows which pins to use. 35 & 36 are the coil and the others the contacts. You would need to find a suitable socket although I guess you could use spade connectors. I would also add 10 amp fuses.
     
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