WFCO WF-8735-AD + LiFePO4: FYI on annoying 'auto detect' quirk

techietab

Posting this so hopefully others can avoid confusion and headaches.

To summarize the issue: The WFCO WF-8735-AD power center that ships with recent model 320 campers has an unreliable battery 'auto detect' feature on the DC converter. While the WF-8735-AD is technically able to autodetect the battery type that's connected, LiFePO4 mode (and associated increase in charge voltage) only seems to be activated if a LiFePO4 battery is attached in a deep discharge state. This mode is also transient, with a variety of conditions causing the power center to transition back to behaviors intended for LA/AGM batteries. This can result in chronically undercharged batteries, or worse, unexpectedly undercharged batteries. 

And here's the real fun part - you could tell what mode the power center's converter is in at glance...if WFCO had bothered to make the diagnostic LED visible from the front of the unit. Instead, it's buried deep inside, so you either need to break out your multimeter to diagnose, or you need to open up the power center and pull the converter unit out of the enclosure to observe during troubleshooting. The exposed high voltage components make it that much more fun!

Apparently, I'm not the first one to notice this. There's even a thread here on the forum that describes exactly the symptoms that this quirk is causing for me, but doesn't identify the cause: 

• https://tab-rv.vanillacommunity.com/discussion/14531/power-converter-not-charging-battery

And discussion elsewhere:

• https://diysolarforum.com/threads/wfco-autodetect-charging-issues.43124/
  
• https://www.forestriverforums.com/forums/f218/wfco-8735-non-lithium-performance-with-lithium-batteries-240825.html#post2767530
  
• https://diysolarforum.com/threads/wfco-auto-detect-converter-does-not-auto-detect.45508/
  

The latter thread references the apparently 'official' WFCO workaround for this issue, which is unfortunately incredibly inconvenient and annoying. It requires yanking the converter out to observe the diagnostic LED, hooking up a discharged battery, and turning it on and off to attempt to get it to recognize the LiFePO4 battery that's connected. Even if you do manage to trigger LiFePO4 mode, the converter may transition back to LA/AGM mode. In my case, disconnecting both shore and battery power to do some electrical work caused the converter to exit LiFePO4 mode and return to LA/AGM mode.

pthomas745

Would you be able to use the Victron app to discover the converter's mode?

stp2136

I have noticed the same problem in my 2022 320s with the WF-8735-AD converter (doesn't recognize the Li battery).  Does any one know if the earlier WF-8735/Li converter works correctly when switched to the Li setting?

Seems like it would be good if NuCamp would switch to another converter till WFCO fixes the problem as many of us are using Li batteries now.

techietab

If you have a Victron SmartShunt installed you should be able to make a reasonably confident guess about the state of the WFCO converter based on the wattage and amperage values. There's a good example with screenshots in the discussion on the Forest River forums that I linked above.

Victron SmartSolar chargers such as the stock 75/10 that's included don't provide enough information to guess one way or the other.

AldebaranJill

I never got my old (2012) WFCO to fully charge any of my lead acid batteries because it too never got to advertised spec voltage. I dont trust WFCO.

My solution was:

techietab

Yep, I've given up on the onboard converter. Installed a Victron IP22 last weekend (12v/15-30A) and it's been working great.

SLJ

Good to know. Looks like the WF-8735LiS (switched) would be a better choice for a Lithium upgrade over the -AD if you can find one.

carpense

@techietab, thank you for sharing the details of this known issue. You mentioned the problem occurs with the WFCO WF-8735-AD. 

Do you know if it is occurring in the WFCO WF-8955-AD (2021 Tab 400) as well? 

techietab

carpense said:

@techietab, thank you for sharing the details I’d this known issue. You mentioned the problem
occurs with the WFCO WF-8735-AD. 

Do you know if it is occurring in the WFCO WF-8955-AD (2021 Tab 400) as well? 

I can't verify it personally (I only have a WF-8735-AD) but there's discussion in the last of the threads I linked above that indicates the 8955 model suffers from the same issue.

dsfdogs

I had  the 8735LiS in my 320S and it worked as expected with the Battle Born battery. The control switch and accompanying led on the front panel confirmed the mode it was in. Unfortunately, WFCO doesn't appear to be making them anymore. 

I now have the WFCO 8955-AD-WAGO on my 2023 400. (This is the style given to me by nuCamp customer service. One of the changes to the 2023 model year is "switch connector type to WAGO"). I've only had it a few days and haven't tested battery charging, but this is the response from Jordan in Tech re the issue:

"The auto-detect figures out the battery chemistry from the charging cycle. It works best if you run the battery dead and then let the converter charge the battery up to 100%. It works better if you remove all other charging sources for this first charge cycle (like the solar controller/7-pin) & heavy loads from the equation, so they don't throw off the charging algorithm."

I told him this wasn't reasonable and per other's experiences, once in lithium mode didn't mean it would stay there.

@techietab how did you install the IP22? I read on one of the forums someone disconnected the power to the converter, removed that portion from the WFCO box and inserted the IP22 into it's space.

Thanks,

techietab

@dsfdogs, I installed it directly inside the trailer tongue box, since I've done a decent amount of driving in the rain and never had an issue with water intrusion into that space. As for removing the stock WFCO converter and installing the IP22 in its place - I'm not sure how that would be possible. The IP22 is fairly large, I don't see how it could fit in that space.

dsfdogs

@techietab how did you wire it? Is the charging component of the WFCO being utilized at all?
Thank you

techietab

@dsfdogs - The output on the IP22 is wired to the bus bars I installed in my tongue box to make cable management easier. The input (a normal 110v NEMA 5-15 plug) is loose inside the tongue box, and when I need to connect it, I run a 12ft extension cable from one of the exterior 110v side outlets on the starboard side of the camper, up through the hole at the back of the box where the propane regulator is, and plug the IP22 in. This allows me to keep the tongue box closed and locked while the IP22 is connected. 

I have not bothered to disable the WFCO charger/converter. Whenever I have the IP22 connected to power, I disconnect the batteries from the camper via the stock battery disconnect dial, so the two charging sources aren't ever competing with each other. 

stepheng

The WFCO 8735 has a 30A fuse for the charger circuit going to the battery. This means that there must be separate converter and charging circuitry in the unit.  When on shore power the converter will supply voltage to the 6 DC circuits but disconnect the battery from them and only supply charging voltage to the battery as required (bulk, absorption, float, etc).  When disconnected from shore power the battery must be connected to these 6 DC circuits to power them.  This means there is a relay (physical or solid state) that disconnects the battery from the DC circuits when on shore power and re-connects them when no shore power is present.

Anybody looked inside one of these units and determined how this works or have an internal schematic?

Ideally we could disconnect the internal charger of the WFCO 8735 and externally install a Victron IP22 in its place to charge the battery when on shore power and use the WFCO to reconnect the battery when no shore power present.

techietab

Important preface to the following for anybody that stumbles on this in the future: I have fairly good knowledge of (very) low voltage telecom/computing circuitry, but I am NOT an electrician and do not claim expert knowledge of WFCO power centers. AC current and the systems that convert it to DC scare the bejeezus out of me, for good reason. Don't construe anything I say here as advice for what you should do with your own WFCO system. Fooling around with AC to DC conversion components is a dangerous and potentially deadly endeavor.

In my (amateur) view, the WFCO 8700 series manual doesn't provide enough information to make it clear if the AC to DC converter can be bypassed without compromising the ability for the battery to feed the DC circuits. But it seems like it might be possible.

Page 4 outlines the DC side of the system. Without going to trace wiring on my 2022 320S, circuits F1-F5 seem to be set aside for feeding 12v DC to onboard systems. F6 is probably connected to the battery, with the fuse under it being reserved as a safeguard against accidental reverse-wiring the battery.

If you look at the AC side of the power center on page 6, it's implied that the entire DC side of the system is wired in via the Green, Black and White trio of wires. White seems to be joined into the AC neutral bus bar, which makes me think that interrupting the circuit by detaching or clipping the Green or Black 'from converter' wires would effectively isolate the DC side of the system from the AC side.

That said - I don't actually know if that would be effective. I have not yet bothered to trace the 'behind the panel' wiring in my camper, and I haven't tried to disconnect the above-mentioned wires.

Pending further advice from a qualified person or evidence-based claims from someone brave enough to attempt the above, I would not encourage folks that don't have intimate knowledge of such systems to fool around with this, because I have no idea what exactly is on the WFCO DC to AC converter board. Even if not connected to shore power, there's the remote risk that the board contains capacitors that could emit a deadly level of current.

carpense

We installed the WF-8955 AutoDetect motherboard assembly in our Tab 400 about a month ago to charge 2 brand new Lion Energy lithium ion batteries. Long story short, we were finally able to get it to charge using the lithium charging profile. The little blue light was on and we thought we were done. 

Fast forward a month...  We noticed the batteries were charging very slowly again.. and not to 100%. Opened up the WF-8955 and found the dreaded "green light" was on indicating the charger was back to using the lead-acid charging profile. 

Called WFCO and found out our converter has an out-of-date firmware version. We need to send it back to the factory to have it upgraded. I asked if they would swap it out for a converter that is permanently set to the lithium ion charging mode. I was told they don't have one - but if I wanted, they could install a jumper that would put it in lithium ion mode permanently. 

This will take 3 - 4 weeks. UGH. Thankfully, we still have the original 8955-PEC motherboard that we previously removed - and we can reinstall it while the new unit is being upgraded.  But what a hassle. 

Before I get my hopes up, has anyone else had WFCO update the firmware and jumper the converter to permanently use the lithium ion charging mode?  If so, did it solve the problems?

JamesC

I was able to purchase the 8955LIS-MBA last fall from Amazon but I’m not sure that it’s still available. You need the kit that includes the fuse panel replacement(it has the switch on it). It’s charging my lithium battery to 100% and since I don’t plan on ever going back to lead acid I’m not sure why I would want auto detect at this time. It’s too bad the company has abandoned a good product in favor of one that is causing so many problems

SLJ

I skipped upgrading to the "Auto Detect" WFCO. Way too many problems with it. Added a Victron Smart Charger when I upgraded to Lithium. The older WFCO will supply DC when on shore power and the Victron will charge the lithiums when on shore power. When I disconnect from shore power I'll just switch the batteries back on.

KK1L

@carpense Do you have a direct contact at WFCO I could ask about the firmware and/or jumper? Or did you go in the front door?

carpense

@KK1L I called the main tech support line and talked to Janice (tech). She had a few questions for me that required me to pull the converter out. Also needed to provide proof of purchase. Hope this helps. 

carpense

Our WFCO 8955 AD Motherboard came back from warranty repair. The manufacturer:
- updated the firmware
- jumpered the board to stay permanently in lithium mode.

It’s only been a day - but so far so good! Blue light on and charging in lithium mode. 

jmcgonig

Jumped the board - would love to see/know what they did to do that

KK1L

I assume it would be too much to ask to see this picture of your updated board?

carpense

@KK1L, I’m sorry. It’s all buttoned up now. I just spent a few days camping with the updated 8955-AD. As a recap, WFCO updated the firmware and - at my request - “jumpered” the motherboard to remain permanently in Lithium ion mode. 

It ran perfectly for the entire trip. Ran in Li-ion mode. Kept the battery fully charged. It seems that the tow vehicle and solar are both doing a better job charging the batteries now. Fully charging them. 

If your converter does not have the latest firmware, I highly recommend you send it in for the no cost update. Then, if you want the converter to remain permanently in lithium ion mode, I would suggest having them jumper it. I suspect they would tell you how to jump over it yourself, but I would imagine doing it yourself would void the warranty.

KK1L

@carpense Thanks. I suspected as much. If you ever have the need to open it up again take a phone.

My guess is that the FW is required to enable the jumper to work...wherever they put it. I do have the tools to push the FW to the uP, but highly doubtful they would share. Will let folks know if I have success.

SLJ

They should just go back to having a switch. It's not like you change battery types every day.

jmcgonig

KK1L said:

@carpense Thanks. I suspected as much. If you ever have the need to open it up again take a phone.

My guess is that the FW is required to enable the jumper to work...wherever they put it. I do have the tools to push the FW to the uP, but highly doubtful they would share. Will let folks know if I have success.

Yes, please let us know if you get anywhere. 

carpense

@KK1L, I had a chance to open up our factory updated (firmware and jumper) WFCO 8955-AD.

I’m including 3 photos (2 sides and top of unit).

Gotta say, it warms my heart to see that little blue light glowing!

Let me know if these photos help at all.

DaveC

My 2023 400 with WFCO 8955-AD has the green light problem. I have tried running the battery down to reset with no change.  Victron solar controller will charge battery to 14+ volts, so I am going to leave it till winter. 

I did find a way to check green/blue without removing the controller.  Remove the drawer, undo and remove the panel above the controller. Darken the trailer and you can see the dreaded green light reflection.

  

KK1L

@DaveC You can see the glow in a darkened trailer at the venting under the WFCO unit. It is not nearly as clear as what you show.

@carpense Yes, that is very helpful. They put a pull-down resistor at the SW (assume this means switch) connection on the header. I am surprised they did not jumper it to ground. On your original image can you tell what colors the bands are on the resistor?



It does look to me like they did accomodate to assemble the unit as a LI only version by mounting the 10k Ohm chip resistor in this other location (from pull-up to pull-down)...not an unusual thing to do when designing boards.

rfuss928

KK1L - Nice catch.  
Hopefully this leads to a DIY fix when I and others make the switch to Li battery(s).  Thanks!