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TheLostBoy's avatar
TheLostBoy
Explorer
Jul 27, 2017

How to wire 12v Converter w/2 blue, 1 red, and 1 white wire

Hello,
We purchased a pretty old camper that we're trying to fix up and it came with a converter wired up, but it wasn't working. I purchased another from a wrecker and wired it up the same way, and it shortly blew as well (fuses became welded in the unit). I purchased one more and I'm wondering if it was wired incorrectly and that's why it was blowing them.

The "new" converter I have is quite different and it has two blue wires coming out along with one red and one white. I know the white is the negative 12v and the two blue are the positive (hot) 12v (as I'm getting about 14v out of them when I connect it to 110 AC). But why are there two blue wires, and what is the red for? Do the blue wires get connected together when putting them back on the circuit block?

With the original converters, there was one blue wire and one white wire. The white went to the negative bus/block, and the blue went to a fuse block which branched out to all the 12v circuits. What I think blew the second converter is that the positive from the battery also goes to one of the posts on the circuit block (but has a switch on the line to turn it off). I'm assuming that this was so the battery could charge off of the 12v feed when the converter was sending power, and power the lights when the converter was off. I'm not really experienced when it comes to power, but is this the right way to wire things up?

Also, the converter I have has a switch on the front that has three modes: Converter / Off / Battery
Converter makes sense (this is when I was getting the 14v on the two blue wires), but what does "Battery" do? I flicked the switch to that thinking that it might put out 12v on the red wire perhaps to charge it, but I didn't read anything (or perhaps it's a trickle charger and I'm just not sure how to set my multimeter to pick up any reading)?

To add to the confusion, there are two breaker switches on the front as well. I assumed that one was for each blue wire (like two separate circuits), so I thought I'd test it out. I killed one breaker and checked one blue/white wire combination and I was suddenly getting 2.8v or something close to that. I checked the other blue wire with the white and same thing, 2.8v! I turned that breaker back on and killed the other one and checked the blue wires. They were both getting close to 2.8v again. Perhaps I'm not understanding the purpose of those breakers? I've never seen a breaker that didn't kill a circuit completely, but these seem to cut the voltage down to 1/4.

Here is what I have right now. I think it's pretty simple, but I just don't think that it was originally set up right (as I've seen some diagrams online that connect the converter to the battery and then the battery to the circuit block, but that doesn't feel right either):




I'd appreciate any help or feedback anyone could give. I tried searching Google for a couple hours, but I couldn't find anything for my specific issue (most converters seem to just have one positive and one negative 12v output wires.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    ASounds like a B&W or Magnetek converter

    Red is positive to part of the fuse block
    Blues are battery and the rest of the fuse block
    When you are NOT hooked to shore power they all hook up together

    Two suggestions, both the same URL (Bestconvter.com) you can order a nice Progressive Dynamics 4600 to replace just the "Guts" of that converter

    And on the left side if you scroll down you will find instructions, possibly even a video on how to do the job.
  • Breakers are for 120v AC, the regular household outlets and how the converter gets power.

    Red is battery + input, blues are two seperate circuits (fused on the front of the power center), you do not have to use both, cap one off if ya like.

    Power centers with conv/off/batt do not charge batts, in the batt position, 12v enters via the red wire and goes out the blue, in conv position, the batt is disconnected and 12v converter dc goes out the blue, the white is neg/common/chassis.

    In OFF, both the converter and battery are disconnected.
  • A make and model of the converter would help. Older B&W and Magnetek models used 3 wire outputs- white red, and blue. The white is negative, red to the battery, blue to the fuse panel. There is an internal relay which switches the battery out of the circuit when power is present, and charges it.
    The wiring you have looks jury rigged, at best.

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