Smoking Power Converter

[p40whk]

Just 3 months out of warranty and the Power Converter started to smoke and melt the plastic while running the heat pump on AC this weekend. WFCO wouldn't replace it so I have one on order along with new breakers. Looks like some of the wires shorted out, not sure which ones are the culprits as it's pretty fried but I will definitely make sure my wire routing is better than this crap! The breakers did not trip when I started to smell the melting plastic!

[Marc G]

Loose connection ? Third from the right looks loose.

[nayther]

you AC power does not run "through" the converter, it comes from shore power directly to hot and neutral buses where the breakers attach. As suggested I would suspect a lose connection, either that common bus bar or at the breaker. Lucky you were in the rig when it happened, that could have been very ugly

[Scrapper]

Hope you ordered a replacement from Progressive Dynamics. 100% better than WFCO.

[p40whk]

Originally Posted by Marc G

Loose connection ? Third from the right looks loose.

It wasn't, not sure why the screw is backed out like that but I just disconnected those and they all seemed tight.

[p40whk]

Originally Posted by Scrapper

Hope you ordered a replacement from Progressive Dynamics. 100% better than WFCO.

No, just the same thing, I couldn't find a match for the WFCO so if you have a source please pass that on as I can cancel the order.

[p40whk]

Originally Posted by nayther

you AC power does not run "through" the converter, it comes from shore power directly to hot and neutral buses where the breakers attach. As suggested I would suspect a lose connection, either that common bus bar or at the breaker. Lucky you were in the rig when it happened, that could have been very ugly

Agreed, it wasn't that hot out this weekend so I was only running the AC for a short time. The attachments seemed tight when I disconnected them but there were a lot of wires rubbing against each other

[pgandw]

Originally Posted by p40whk

No, just the same thing, I couldn't find a match for the WFCO so if you have a source please pass that on as I can cancel the order.

The Progressive Dynamics PD4135 is a "drop-in" replacement for the WFCO 8735P used in the A-frames. I have done the replacement in both my A-frames because the WFCO never went into "trickle" mode, and over-charged my batteries (boiled the water) went I left the unit plugged in inside the garage for a month or more. I think each time it cost me about $150 for the PD 4135 unit.

The PD4135 cutout dimensions are not exactly the same as the WFCO but I was able to make it fit and still look good. I think I added a piece of wood trim around parts of the case.

You do have to remove every circuit and move it to the 4135, but it looks like you are going to be doing some re-wiring anyway. I used the occasion to clean some of the rat's nest of wire nut connections behind the converter by installing a couple of bus bars - one for DC negative, and one for the DC "everything else" positive circuit.

From the look of the photos, I would also consider replacing the AC circuit breakers above the burned wiring (ordinarily these are just moved over from the WFCO to the PD). Breakers are not expensive at Home Depot. When I did mine, I installed half thickness breakers so I could have a separate breaker for the converter (WFCO lets Forest River pair the converter with the fridge AC on the same breaker - which I think is stupid).

I pulled out the WFCO unit onto the floor next to the PD unit, and moved one circuit at a time, tested that circuit, then onto the next, until I was done. Total time about 5 hours - but I'm slow. In addition to the bus bars (if you put them in), you will want new wire clamps for the AC circuits - I couldn't reuse the plastic garbage clamps FR used when wiring. I also used waterproof in-line wire connectors for the DC circuits where the wires didn't go to the bus bars - the kind you use a blow drier or paint strip gun to shrink the seal onto the wires.

Finally, as you test each circuit, makes notes as to what is on that circuit. The FR labels are incomplete. That's how I found out both the A/C and heater won't work without the thermostat DC circuit. And all the little things that are on the "everything else" DC circuit.

I'm very sorry for the fire; I'm very glad the damage was limited. Hope this helps. I think I put more detail in some earlier A-frame threads.

Fred W
2019 Flagstaff T21TBHW A-frame with 2 Costco/Interstate GC-2 batteries, PD 4135 converter/panel
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time
last trip: Black Hills, Badlands, Ft Robinson, Scott's Bluff
next trip: Navajo Lake, NM

[Flybob]

This appears to be the power distribution panel and not the converter. The converter converts 120VAC into 12VDC and have no connection to the heat pump. The damage appears to be from a high resistance connection possibly from a loose connection. It is a good idea to check the connections in the distribution panel once a year.

[p40whk]

Thanks Fred for the info. The only problem with the PD4135 is that is only has 5 DC circuits and not 6 like the WFCO so I'm not sure how it is a direct replacement? I have an A122THESP which uses all 6 of those circuits so I did not want to loose one.


I already have the replacement breakers as well, the originals got pretty hot. I also labelled all of the wiring as I disconnected it so it should be easy to put the new unit in once it arrives.


Waterproof connectors will be used, great minds think alike! If the WFCO unit doesn't last this time then I'll consider the switch to the Progressive unit. Honestly, this happened because of the way FR installed it and not the controllers fault so I'll give it another chance!

[p40whk]

Originally Posted by Flybob

This appears to be the power distribution panel and not the converter. The converter converts 120VAC into 12VDC and have no connection to the heat pump. The damage appears to be from a high resistance connection possibly from a loose connection. It is a good idea to check the connections in the distribution panel once a year.

Agreed, I just used the name of the WFCO unit since it does both. None of the wires were loose in any of the bus bars so my guess is that it was wire on wire rubbing that caused the short. Either that or they stripped to much insulation off the wires when they installed it. Too hard to tell given how much all the wires are burnt.

[pgandw]

Originally Posted by p40whk

Thanks Fred for the info. The only problem with the PD4135 is that is only has 5 DC circuits and not 6 like the WFCO so I'm not sure how it is a direct replacement? I have an A122THESP which uses all 6 of those circuits so I did not want to loose one.


I already have the replacement breakers as well, the originals got pretty hot. I also labelled all of the wiring as I disconnected it so it should be easy to put the new unit in once it arrives.


Waterproof connectors will be used, great minds think alike! If the WFCO unit doesn't last this time then I'll consider the switch to the Progressive unit. Honestly, this happened because of the way FR installed it and not the controllers fault so I'll give it another chance!

I was confused at first, too. I spent way too much time figuring it out. The WFCO had 7 fuses and the PD only had 6. The WFCO has reverse polarity fuses as part of the circuits, and the PD either doesn't have them, or they are embedded on the converter board. When you go to the back of the WFCO, there are only 6 DC circuits coming out.

I just went out to the trailer and verified that my PD4135 has 6 fuses and 6 DC circuits.

I would have never noticed the WFCO failure to charge properly except that one of my dual 12V batteries got too dry and crapped out. It sucked the good battery dry, and the WFCO blew fuses. I ended up losing track of what happened, recharged the good battery with a separate charger, and re-paralleled the batteries, forgetting that one was defective with no charge. The resulting fire in the battery box was impressive, but was quickly put out by cutting one of the parallel cables.

As a result, I installed a cut-off switch, replaced the batteries with dual 6V GC-2s, installed a voltmeter, and replaced the WFCO after confirming it was locked on 13.7V. On my current A-frame, I measured the output voltage from the WFCO from the get-go. It never wavered from 13.7V, so I replaced it right away with the PD 4135.

If you aren't plugged in long term, and don't use a generator to recharge your batteries (when recharge time matters), the WFCO shortcomings I experienced won't affect you.

Fred W