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

TheLostBoy
Explorer
Explorer
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.
13 REPLIES 13

TheLostBoy
Explorer
Explorer
MEXICOWANDERER wrote:
For SCHOOL purposes measure voltage blue wire to blue wire.

I do need a lot of schooling, but I thought the white wire was negative, so would it work to measure the blue to the blue (both positive, no)?

MEXICOWANDERER wrote:

0 voltage? It won't hurt a thing to parallel them.

I don't think I'll need to. One will be enough as I'm just powering some lights and a water pump. Very small camper.

MEXICOWANDERER wrote:

Be aware in a saturated transformer system adding ANY FORM of capacitance on the ouput will automatically raise voltage. When these brontosaurus walked the earth giant stereo systems for cars did not exist. Connect a boom-thump audio amplifier to a ferroresonant charger and the regulated voltage will soar. Been there done that...

Yeah, I don't think I'll be doing that then. I'm sure the voltage coming out of it will be enough and it will drop when I start drawing. Though, I might try that trick you mentioned of connecting the light, THEN testing the output (if I have time).

TheLostBoy
Explorer
Explorer
red31 wrote:
note the little window at the bottom right that has fuses.
one for each 12v circuit so you can use 1 blue for 1 circuit and the other for something else

Yeah, that PDF almost looks like the one I have (minor differences like button sizes/colour), thank you! I don't think I'll need the other circuit then. I really just want to run my lights and one water pump for the sink.


red31 wrote:

also note it is not suitable for charging.

That's good to know and I think THAT is the cause of the issues I've been having as the batter has previously been connected to the 12v output on the converter. All I need to do now it add some other switches or some way I can put in a battery charger so it doesn't damage anything else.

red31 wrote:

Extra breaker for optional 120vAC circuit. (for a battery charger!!!!)

Why you get 2.8v without power????, was battery hooked up, were you holding your mouth right?

Huh? I don't follow. The second breaker is for a battery charger? How would that hook up?
I got 2.8v when I had one of the blue breaker switches on and one off (didn't matter which one I had turned off) and I got it off of both of the blue wires (using multimeter on the blue and white 12v output wires). Does that make sense?
...Holding my mouth? Not sure what that means? Is that a joke that I missed or should I not be breathing something in?

MEXICOWANDERER
Explorer
Explorer
For SCHOOL purposes measure voltage blue wire to blue wire. 0 voltage? It won't hurt a thing to parallel them. Be aware in a saturated transformer system adding ANY FORM of capacitance on the ouput will automatically raise voltage. When these brontosaurus walked the earth giant stereo systems for cars did not exist. Connect a boom-thump audio amplifier to a ferroresonant charger and the regulated voltage will soar. Been there done that...

red31
Explorer
Explorer
http://www.progressivedyn.com/pdfs/688%20owners%20manual.pdf

note the little window at the bottom right that has fuses.
one for each 12v circuit so you can use 1 blue for 1 circuit and the other for something else

also note it is not suitable for charging.

Extra breaker for optional 120vAC circuit. (for a battery charger!!!!)

Why you get 2.8v without power????, was battery hooked up, were you holding your mouth right?

TheLostBoy
Explorer
Explorer
MEXICOWANDERER wrote:
Connect blue wires to a 12 volt light then measure.

Do I connect both of them, or do one at a time? And if I do only connect one wire, do I measure on the blue wire connected, or on the second, unconnected wire?

MEXICOWANDERER wrote:
These suckers have more Ripple than a Downtown Central liquor store.

Ha! That's good, I gotta use that.

MEXICOWANDERER
Explorer
Explorer
Flaky at best these converters slump their voltage when connected to a load. They cannot be analyzed disconnected. Connect blue wires to a 12 volt light then measure. These suckers have more Ripple than a Downtown Central liquor store.

TheLostBoy
Explorer
Explorer
Ok, I thought it would just be simpler to answer all questions in one post with quotes from each responder below:

Chris Bryant:
"A make and model of the converter would help"
Sorry, should have grabbed that info. I'm at work now, but I have the photos that the fellow who originally sold it to me sent me:


It looks like a Progressive Dynamics power converter (can't read the model number, but I'll try to grab it tonight if I can remember)

"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."
White and blue made sense (though, not why there are two). It was the red that I had no clue about. Thanks! I'll try connecting it to the battery, and I really hope this guy has a charger built in, that would be REALLY handy.

"The wiring you have looks jury rigged, at best."
Yep! This is how I got it and I'm trying to clean it up.


red31:
"Breakers are for 120v AC, the regular household outlets and how the converter gets power."
If the breakers are for the 120v power coming in, how come killing one of the breakers doesn't cut the power completely?

"Red is battery + input, blues are two separate circuits (fused on the front of the power center), you do not have to use both, cap one off if ya like."
Thanks, I'll probably just cap the second blue wire as I don't think I need two. This was one of my biggest questions.

"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."
Darn, I was hoping that this unit would also charge/maintain the battery when 120v power is connected.

"leave the ground block alone"
I don't know exactly what a ground block is. Sorry.

"disconnect the battery and toggle switch, the power center conv/off/batt will do that function. Connect the batt + to the red on the power center, connect one blue to the fuse block in lug, connect the batt - to chassis or ground block. "
I think I understand what you mean (I think fuse block lug is the bolt at the bottom, and ground block is the negative terminal bus/block, right), but I'll draw up a diagram on what I think I need to do.

"the switch (conv/off/batt) isolates the converter power from batt power."
This is not what I thought it did when I first saw it. I thought there was a charger built in or something."


wa8yxm:
"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"
From what others are saying, the blue goes to the fuse block and red is battery. I did look into a brand new converter, but this camper just isn't worth putting that kind of money into it (we bought it for $1200 and are just looking to fix it up to use for a few years)


MEXICOWANDERER:
I'm getting almost 14v on the blue wires. Should I be concerned? Is there anything I could put on it to regulate it back to 12v (like a resistor)?



Ok, here is what I've drawn up and am going to try (assuming I don't get any negative feedback or recommendations to do otherwise) and to use as a reference for anyone else who stumbles upon this issue with similar questions.
I've left out the 12v branch circuits from the positive fuse block, as well as some of the other 120v outlets, which some may see in the original photo, to keep it from getting too messy.

red31
Explorer
Explorer
the blue output wire(s) are fused in the power center, of course additional fuses along the circuit can be use, the switch (conv/off/batt) isolates the converter power from batt power.

http://d163axztg8am2h.cloudfront.net/static/doc/20/1d/eecf501c1dfabda57921104d5ac5.pdf

MEXICOWANDERER
Explorer
Explorer
Hello: A general question...

Old old Magneteks. Not as old as me but nevertheless impressively obsolete...

Did not these units have a heavy wire or wires to power the fuse panel thereby power the camper loads, lights, water pump? This circuit could never see a direct path to the battery.

A separate circuit, one wire feed the battery. This circuit came from a huge ceramic bleed resistor inside the converter and the most I have ever seen for a charging rate was about three for four amps. I named it "The resistor bleed circuit".

Thus the two separate output wires could not exchange duty. The load wires could not connect to the battery and verse visa. Extrapolating, the OP's two wires are to feed a load fuse panel, while the remaining red wire is connected to the battery? White of course going to chassis negative?

EXTREME care must be taken with these old systems because as the ferroresonant voltage control capacitors age, finishing voltage goes up up up. I have seen 15+ volts and the only way to fix this is to replace all the unit's large capacitors.

I can only wish my own finish voltage ended going up up up...

red31
Explorer
Explorer
leave the ground block alone

disconnect the battery and toggle switch, the power center conv/off/batt will do that function. Connect the batt + to the red on the power center, connect one blue to the fuse block in lug, connect the batt - to chassis or ground block.

wa8yxm
Explorer III
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.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

red31
Explorer
Explorer
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.

Chris_Bryant
Explorer
Explorer
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.
-- Chris Bryant