Adding 12v Accessory with Ignition Switched Power

Discussion in 'Marine Electrical / Electronics' started by ArchHibb, Jan 6, 2019.

  1. ArchHibb

    ArchHibb Captain

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    I want to add a 12v accessory with on/off power controlled by the ignition. I realize there's a million different ways to wire boats, but usually the engine start circuit is separate from the main DC panel, so I supsect the engine/starter circuit is the only one that is controlled by the ignition key.

    Can I connect a relay to the on/off side of the ignition key and use that to control a separate 12v circuit?
     
  2. djmarchand

    djmarchand Captain

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    Yes, no problem doing what you propose.

    David
     
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  3. captjohn

    captjohn Captain

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    Just make sure the load you are adding isn't too much for the ignition switch. If it is, try a switch with a higher current rating.
     
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  4. Keelboater

    Keelboater Captain

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    [​IMG]

    Something like this perhaps? Current does not flow through the switch so acceptable load depends on relay and wire size.
     
    Last edited: Jan 7, 2019
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  5. ArchHibb

    ArchHibb Captain

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    ^That’s what I’m thinking Keelboater, thanks! That way the accessory circuit is isolated from the ignition key circuit and has its own circuit breaker protection.

    Is this how you are wiring your Aqualarms?
     
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  6. Keelboater

    Keelboater Captain

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    The alarms are very low draw so it's not necessary to go this route. Some of the installation is not even tied into the ignition and provides 24/7 coverage.
     

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