How does Converter get it's hot power?

Discussion in 'Wiring' started by McMike, Oct 12, 2020.

  1. McMike

    McMike Member

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    I have a 08 Palomino with a WH8725 converter. The converter has four fuses for appliances. Plus a polarity fuse. The fuse #1 is behaving strangely, pulling it cuts off all power to everything.

    So I traced the wiring and what I determined is the hot (black) wire from the battery is spliced into the load wire for the fridge, but it is downstream of the fuse. What I can't figure out is how the power is supposed to get to the converter.

    There are five wires coming out: Blue, Yellow, Green, Red - for fuses #1 to #4. Plus white common ground. So, where how/where is the 12v power supposed to get into the system?


    converter wiring.JPG
     
  2. WrkrBee

    WrkrBee Well-Known Member Silver Supporting Member

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    The way I read it, power has to feed through Fuse 1 to power the other circuits. Also, the Fridge circuit is not protected. Power from the battery should go to the + bar in the converter.
     
  3. rabird

    rabird Howdy!

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    Last edited: Oct 12, 2020
  4. McMike

    McMike Member

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    converter wiring 2.JPG converter wiring 2.JPG converter wiring 3.JPG So,
    My unit has fuse #4 (red) wired to the furnace and water pump.
     
  5. tfischer

    tfischer A bad day camping beats a good day at the office Gold Supporting Member

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    The label on the back of the converter should have wire color info
     
  6. McMike

    McMike Member

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    converter wiring 4.JPG View attachment 69730
    Aha. Okay. Kinda embarrassing but long story but I just found the stickers...

    The sticker on the back says fuse #4 red = power + appliances. I assume that's the converter manufacturer's sticker.

    The sticker on the front says fuse #1 blue = battery + fridge. That's the trailer maker's sticker.

    In both cases, either fuse #1 or #4, it appears that the battery hot wire indeed splices into an appliance load connection downstream of the fuse.

    Seems like a weird design to me. But I guess that's the way it is done.
     

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    Last edited: Oct 13, 2020
  7. tfischer

    tfischer A bad day camping beats a good day at the office Gold Supporting Member

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    Pretty sure I have this exact same converter (or one very similar) as I had to replace mine a few years ago. I'll be popping it up in a few days and can report back on what I have. I'm almost certain it's the red wire that connected to the battery.
     
  8. MNTCamper

    MNTCamper Well-Known Member

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    Both my original 2001 converter and my newly installed WFCO (8735) had the red wire to the battery. That is the way it should be wired from the factory and it sounds like your wiring was doctored up in a bad way. I would disconnect and pull the converter out and look at the back wiring and also pull the instructions for it from the web.
     
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  9. Treecatcher

    Treecatcher New Member

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    One of the small annoyances for an electronics tech is that while household AC power uses black to identify the "Hot" side, white for "Neutral" and green for "Ground," automotive DC power uses red for "Hot" and Black is the "Ground" side.
    That's the default color scheme, but a manufacturer might use nonstandard colors. I'd guess the yellow, blue, red, and green were used to make tracing each circuit simpler.
    The photo shows a heavier white wire marked +Vcc connected to a 30A fuse, feeding four smaller fuses to four +13.6V circuits. +Vcc usually means a main +13.6V source, so I'd guess it's the main output from the converter.
    I'll toss out a guess that they used a white wire for Vcc to keep it from being confused with the auto's +13.6V battery line, which would be red.
    Why the label calls that white +Vcc line "Negative" has me baffled, though.
     
  10. stierheim

    stierheim Member

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    My take:

    1. While a little unorthodox, there is no safety issue in this style of wiring provided that:
    a. The battery is fused or has a circuit breaker at the battery of 30 amps (assuming 10 Ga wire to the battery via that splice and ground)
    b. The line to the fridge should be inline fused based on the size of the wire from the splice to the fridge. If it is a 12v option fridge, then it should be 14 Ga wire or larger and fused at 15 Amps (close to the splice) or what ever the fridge manufacturer requires.
    2. The converter is improperly fused (under fused which is not a safety hazard). The converter is a 30 amp unit and the circuit to the battery should be fused at 30 amps or the converter may blow the fuse when the full charging output current of the converter is supplied to the battery. In your case circuit #1 (the top fuse) should be 30 amps vice 15 amps (assuming 10 Ga wire to the battery via that splice and ground).

    3. Circuit #1 is also the battery input circuit and it protects all of the other circuits (it acts like a main fuse). Having a 15 amp fuse in circuit #1 is nonsensical to the 20 Amp fuse in circuit #2. A main fuse or circuit breaker rating should be greater than or at least equal to the protection provided to the largest branch circuit the main is protecting. Changing circuit #1 fuse to 30 amps will correct this.
     
  11. SteveP

    SteveP Well-Known Member Platinum Supporting Member

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    You are assuming not only that the manufacturer did it right but that it hasn't been jacked with in the last 12 years. You have the converter's manufacturers documentation, both in the manual provided by Rabird and the pic you posted in post #6 that it's wrong. You have battery power direct to the fridge circuit with the only protection being the inline fuse at the battery positive. Assuming that is fused at 30 amps, if you have any wiring in that circuit or the fridge itself less than 10 gauge you are at risk.

    There should be no appliance branch circuits off of the battery wire, which should be moved to fuse #4. The furnace and water pump should be moved off of fuse #4 to fuse #3. 15 amps is plenty for all 4 items on that circuit.
     
  12. Novarich

    Novarich Active Member Gold Supporting Member

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    Sounds like someone modified the circuit. Does the converter function properly when on shore power and the battery disconnected? Does it supply 12 volts when on shore power and switch over to battery when unplugged? Are they using the line to charge the battery if your converter does not have the function built in? Is it the only wire connected to the hot side of the battery?
     

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