12v Ignition feed for stereo on 24v truck

outdoordan Jan 9, 2019

  1. outdoordan

    outdoordan Member Supporter

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    I've been trying to wire in a stereo. Fun.

    Real mish mash of wires behind the dash. Got several permanent 24v and a couple of 12v feeds but cant find a 12v switched feed off the ignition.

    Can anyone point me in the direction of an easily found 12 switched feed?

    Thanks
     
    hopeless wanderer likes this.
  2. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    I’ve no idea Dan but if you get stuck just wire to a 24v relay and use the contacts to switch your 12v positive.
     
  3. outdoordan

    outdoordan Member Supporter

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    Thanks StarCruiser... not sure how to do that but will look into it.
     
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  4. hopeless wanderer

    hopeless wanderer Well-Known Member I am in england

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    I was looking into this as I'm just about to get a 24v vehicle. It's gonna be a different story for my solar needs but for the stereo I thought id grab one of these.
    https://www.amazon.com/Nextrox-Conv...&sr=8-1&keywords=24+volt+to+12+volt+converter
     
  5. outdoordan

    outdoordan Member Supporter

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    Just bought one. Think I have a switched 24v feed so in theory just plumb it into that and away we go. Going to bang in a couple of fusible links as well.
     
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  6. hopeless wanderer

    hopeless wanderer Well-Known Member I am in england

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    Let me know if it works well and I'll get the same.
     
  7. outdoordan

    outdoordan Member Supporter

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    Will do. As it happens the stereo that I was trying to fit last night was bust. I tried another today with a permanent feed to red and yellow spliced together and it worked fine. It stays on when the ignition is turned off/key out... but I wanted that anyway. Just have to remember to turn it off.

    The fix for this is just a single fused lead off positive of the second battery, through bulkhead to stereo. I may well use the 24v to 12v step down elsewhere or fit it if it looks like I'm having any problems with battery draining.
     
  8. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    Use the dropper. Don’t just use one battery or you will get charging problems. If it was ok to just use one battery, nobody would use a dropper.
     
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  9. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    Intervolt do a good dropper that will charge a leisure battery at 12v 25A.
     
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  10. outdoordan

    outdoordan Member Supporter

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    Thanks. I'll fit the gadget in the next day or two when it gets here.
     
    StarCruiser likes this.
  11. Ben Stratford

    Ben Stratford Well-Known Member Supporter I am in england

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    Agreed, do not take anything from the second battery as a 12v feed or you will be replacing both batteries for fun.
    Ask me how i know!!
     
    outdoordan likes this.
  12. outdoordan

    outdoordan Member Supporter

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  13. outdoordan

    outdoordan Member Supporter

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    Spill the beans Ben...
     
  14. outdoordan

    outdoordan Member Supporter

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    Fitted this afternoon. took this before i tidied it up. multimeter read 25v in, 12v out. piece of cake to fit.5amp, 60watt big enough to run the stereo.

    Left the 12v feed from the battery to the fag lighter in situ but will replace with another beefier one of these as soon as I can.

    32828655318_48cccba8f6_k.jpg step_down_24v_12v by Dan, on Flickr
     
  15. Ben Stratford

    Ben Stratford Well-Known Member Supporter I am in england

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    My 60 is 24V. I kept getting flat batteries, predominantly the near side which had 3 feeds from it. The cable connecting it to the main battery and the connectors were all dodgy too.
    The feeds were upsetting the balance between the batteries leading to one going flat every two weeks and the other overcharging.
    Anyway, after renewing the cables ( thanks to starcruiser for making me some new ones ) and the battery cable clamps and removing the 3 feeds and fitting new batteries again and a new voltage regulator, its been s trouble free 12 months ( kiss of death no doubt! ).
    I installed a dropper ( grateful donation from member -thanks Rich ) and all is well. The feed for the dropper came from the cigar lighter which is switched by the ignition key to a relay to activate the dropper which feeds the rear view camera.
    I did fit a voltmeter to the 2nd battery again via a relay and another to the alternator so i can see whats going on.
     
  16. outdoordan

    outdoordan Member Supporter

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    One thing I've noticed. When I first wired the stereo in on the 12v feed there a was perfect radio reception. Now with it wired in off the 24 >12 dropper its pretty crap... lots of interference. The dropper is installed under the dash. Wanted it to be easily accessible just in case it cooked... if its unshielded it might be worth installing yours in the engine compartment?
     
  17. outdoordan

    outdoordan Member Supporter

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    I have to fit a second dropper for the fag lighter urgently now... long story.

    Only used for charging phones. Does anyone know will 5amp 60w be enough?

    Thanks
     
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