I have seen the light! WFCO "AD" fix

[jlankford]

The blue light, that is.

Many of us know that the WFCO auto-detect converters have issues with properly detecting an LiFePO4 battery. But most of us probably didn't know that WFCO has a service test method for overriding the auto-detect algorithm and forcing the converter into LFP mode.

After one year with our r-pod and almost as long with the upgraded LFP battery bank, I have never seen the telltale blue LED that indicates the auto-detect worked. Typical charging current from this converter has been less than 10amps. I would briefly see as high as 22amps after a reboot, but that would quickly drop back to ~9A after less than 5 minutes. All cable connections are good, the factory used 10awg cable, and the total path resistance between my converter and battery is 0.031 ohm. Note that the resistance of the 10awg copper alone is about 0.022 ohm, so not much left for crimp connections, switch contacts, etc. My TT doesn't have a frame ground problem.

Another forum member recently posted that WFCO sent them a service pin jumper to override the AD and force LFP mode. I was on the verge of replacing the converter wiring with 6awg cable, but after seeing that post I tried this first. WFCO tech support started out by wanting me to do some troubleshooting, but as soon as he learned the size of my battery bank and solar array, he decided to immediately send the service jumper to me. He said the large battery bank (300Ah) and/or the large solar (600 watt) could interfere with the AD algorithm so I needed the jumper.

I'm happy to report that after installing the jumper and restarting the converter I immediately have a blue LED, and I see a sustained charging current of around 27 ~ 31 amps, depending on battery SoC. Voltage at the converter is 14.4VDC. I do see current and voltage drop to 20amps and 14.0VDC occasionally, but it then returns to 14.4V - I assume the converter is testing whether it should remain in bulk mode or drop back to absorption. I've seen the bulk charge cycle at 14.4V continue for 4 hours, or longer.

This model is WF-8735-AD, so maximum current is 35 amps. I'm happy with the 31 amps I'm getting - this is maintained even when the converter is powering other items in the TT. WFCO advised me to replace the 30A blade fuse for the battery with a 40A fuse, but I haven't done that yet. I'll carry some 40A spares in case I need it later. WFCO also warned me that there may be a hidden 30A self-resetting breaker in the circuit, but I haven't pulled down the coroplast yet to look for that, and so far don't need to.

[JimM2109S]

Good news! Glad to hear of your success story.

WFCO needs to incorporate a switch into the circuitry that any owner can flip to Li. Owners should not have to upgrade the wiring between the converter and battery bank (as I did) or call to request said jumper in order to get the rated output from their converters when using a Li battery bank.

[TitanMike]

Using this "service mode" to force 14+ volt charging has both good and bad to it. Good that it forces a bulk mode but bad as when battery reaches 100%SOC iy doesn't drop to a more desirable 13.5 volt "float" voltage.

WFCO does have a later model converter section that has a switch rather than jumper that seems to have solved their all to long lasting problem.

Don't know why it took them so long as most other converter mfr's solved this issue years ago.

[Larry-NC]

Originally Posted by jlankford

The blue light, that is.

Many of us know that the WFCO auto-detect converters have issues with properly detecting an LiFePO4 battery. But most of us probably didn't know that WFCO has a service test method for overriding the auto-detect algorithm and forcing the converter into LFP mode.

After one year with our r-pod and almost as long with the upgraded LFP battery bank, I have never seen the telltale blue LED that indicates the auto-detect worked. Typical charging current from this converter has been less than 10amps. I would briefly see as high as 22amps after a reboot, but that would quickly drop back to ~9A after less than 5 minutes. All cable connections are good, the factory used 10awg cable, and the total path resistance between my converter and battery is 0.031 ohm. Note that the resistance of the 10awg copper alone is about 0.022 ohm, so not much left for crimp connections, switch contacts, etc. My TT doesn't have a frame ground problem.

Another forum member recently posted that WFCO sent them a service pin jumper to override the AD and force LFP mode. I was on the verge of replacing the converter wiring with 6awg cable, but after seeing that post I tried this first. WFCO tech support started out by wanting me to do some troubleshooting, but as soon as he learned the size of my battery bank and solar array, he decided to immediately send the service jumper to me. He said the large battery bank (300Ah) and/or the large solar (600 watt) could interfere with the AD algorithm so I needed the jumper.

I'm happy to report that after installing the jumper and restarting the converter I immediately have a blue LED, and I see a sustained charging current of around 27 ~ 31 amps, depending on battery SoC. Voltage at the converter is 14.4VDC. I do see current and voltage drop to 20amps and 14.0VDC occasionally, but it then returns to 14.4V - I assume the converter is testing whether it should remain in bulk mode or drop back to absorption. I've seen the bulk charge cycle at 14.4V continue for 4 hours, or longer.

This model is WF-8735-AD, so maximum current is 35 amps. I'm happy with the 31 amps I'm getting - this is maintained even when the converter is powering other items in the TT. WFCO advised me to replace the 30A blade fuse for the battery with a 40A fuse, but I haven't done that yet. I'll carry some 40A spares in case I need it later. WFCO also warned me that there may be a hidden 30A self-resetting breaker in the circuit, but I haven't pulled down the coroplast yet to look for that, and so far don't need to.

Could you post pictures of the jumper and where it goes? Or even just scans of the jumper installation instructions? It seems as if you know you've installed LiFePO4 batteries, there's no possible harm.

[jlankford]

Originally Posted by TitanMike

Using this "service mode" to force 14+ volt charging has both good and bad to it. Good that it forces a bulk mode but bad as when battery reaches 100%SOC iy doesn't drop to a more desirable 13.5 volt "float" voltage.

WFCO does have a later model converter section that has a switch rather than jumper that seems to have solved their all to long lasting problem.

Don't know why it took them so long as most other converter mfr's solved this issue years ago.

Actually, the behavior of the converter with the jumper is now exactly what is wanted.

As the LFP battery reaches full, the charge current drops off pretty fast. Within 5 minutes the current dropped from 21A down to 1A. As the current was quickly dropping from 3A, then 2A, then 1A, the converter suddenly switched off the cooling fan and the current dropped to 0.0A. The voltage at the converter was now 13.7VDC. Moments before it had been 14.6VDC. So, the converter decided to exit bulk mode and drop to its LFP absorption voltage pretty much immediately upon detecting that the battery was full. The LFP blue LED remained lit.

The service jumper appears to force the converter into full LFP operation, not just into LFP Bulk mode.

[jlankford]

Originally Posted by Larry-NC

Could you post pictures of the jumper and where it goes? Or even just scans of the jumper installation instructions? It seems as if you know you've installed LiFePO4 batteries, there's no possible harm.

The procedure is simple...

"Unplug from shore power, turn the battery disconnect, install the jumper, and then do the reverse."

The last picture of the jumper is from forum member g.spalding. The instructions given to him were that the jumper could be later removed. But in my case, the WFCO tech said to leave the jumper installed to prevent my large battery bank or the solar voltages from later confusing the converter to drop out of LFP mode.

[Larry-NC]

Originally Posted by jlankford

Actually, the behavior of the converter with the jumper is now exactly what is wanted.

As the LFP battery reaches full, the charge current drops off pretty fast. Within 5 minutes the current dropped from 21A down to 1A. As the current was quickly dropping from 3A, then 2A, then 1A, the converter suddenly switched off the cooling fan and the current dropped to 0.0A. The voltage at the converter was now 13.7VDC. Moments before it had been 14.6VDC. So, the converter decided to exit bulk mode and drop to its LFP absorption voltage pretty much immediately upon detecting that the battery was full. The LFP blue LED remained lit.

The service jumper appears to force the converter into full LFP operation, not just into LFP Bulk mode.

In other words, all the jumper does is disable the Auto-Detect function and force LFP operation, but does not disable the LFP charge/float function. That sounds like a good solution, and some foresight on the part of the designers, i.e., "In case there's some installations we haven't foreseen that fail to detect an LFP battery, let's add some jumper pins to override the auto-detect feature." What surprises me is that they are so cautious about issuing the jumper plugs.

[kipkohl]

What are you showing in the third photo? I see the jumper plugged in at the bottom, but what are the multiple arrows indicating? Where does the other end of the jumper plug in? Sorry if I’m missing something obvious.

[jlankford]

Originally Posted by kipkohl

What are you showing in the third photo? I see the jumper plugged in at the bottom, but what are the multiple arrows indicating? Where does the other end of the jumper plug in? Sorry if I’m missing something obvious.

The photos are from the WFCO service tech. I think he is trying to show that you need to push the circuit board to one side to reach in there. I didn't like the idea of flexing the PCB, so I removed the fuse board instead to get it out of the way. The jumper plug doesn't connect to anything else. It plugs onto the 6-pin connector on the circuit board and shorts pins 1 & 2 together.

[kipkohl]

Ok gotcha, thank you