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WFCO 8955-AD jumper

RobermcmRobermcm Member Posts: 84
After learning about the WFCO issues with auto detect, I checked out the charging status of my 2023 tab 400 with the battleborn 100ah lithium. The led was ‘green’ and the charge voltage limit was in the 13 volt range versus recommended 14.4v. 

So, I wrote to WFCO and got the ever friendly Shaun technician. He asked me what my software version was, and I could not find it anywhere on the face plate of the charger, even after multiple suggestions from Shaun. He then, oddly, offered that I should not have any problem with my auto detect. I wrote back that I really just wanted the jumper solution based on the forum experiences I’d read from many. Doing what WFCO recommended, didn’t seem to make it sticky to a lithium charging profile. Shaun replied that he’d ship a jumper out that day, which he did! 

Picture attached. No instructions, just the jumper. I guess my email confidence implied skills with the converter. There probably aren’t that many six pin connectors on the circuit boards, right?  The shrink wrapped jumper appears to be a resistor folded in half and pressed into the blade connectors of locations 5 and 6 (marked) of the six pin plug. I didn’t cut off the shrink wrap, but would if asked, before I install it to benefit others with the AD issues. 

My only question is whether there are instructions for jumpering the 8955-AD. I recall instructions for the 8755, I think. 

Thanks all. 
Rob


2023 Tab 400
2015 Audi Q7 TDI
Northern Ohio

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    MuttonChopsMuttonChops Member Posts: 1,604
    Robermcm said:
    . . .  No instructions, just the jumper. I guess my email confidence implied skills with the converter. There probably aren’t that many six pin connectors on the circuit boards, right?  

    For fun I searched the WFCO literature for PCB images of the 8955-AD product.
    The best image (below) has One Six Position Connector location = = J4 = =

    Image however does now have the Header installed, mate for the Jumper Plug they shipped you.



    '18 320 Spitched axle, 3020HE; PNW based
    TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
    Adventures:  51   Nights:  322  Towing Miles 41,200+
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    RobermcmRobermcm Member Posts: 84
    edited April 11
    Thanks. Good research. Why am I not surprised!  

    Which pins do you think are 5 and 6? Based on the double line to the right side of the pcb outline, I’d think that was where your connector had the tall side. If I make my female connector fit (upside down ‘L’) 5 and 6 would be at the top. Is there pcb board convention that might say otherwise? Like ‘1’ starts nearest the connection label of J4?
    2023 Tab 400
    2015 Audi Q7 TDI
    Northern Ohio

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    MuttonChopsMuttonChops Member Posts: 1,604
    Robermcm said:
    Which pins do you think are 5 and 6?

    I have no idea.
    Suggest you open-up the Power Center and inspect the installed PCB . . . it might have the socket.

    If not, take a picture and send to WFCO support person that provided the 'jumper' and ask for guidance.

    Let us know what you discover/learn.
    '18 320 Spitched axle, 3020HE; PNW based
    TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
    Adventures:  51   Nights:  322  Towing Miles 41,200+
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    RobermcmRobermcm Member Posts: 84
    I’ve yet to install this jumper, but I did put a meter on it to determine what was hiding in the shrink tubing. It’s just a 1k resistor. Pins 5 and 6 jumped with it. 

    Waiting to get a little more experience with this new to me tab 400, wfcom8955-AD converter and the 100ah lithium battery. So far the solar keeps it topped up just fine, but I haven’t drawn it down deeply, and in that moment, I’ll want a faster recharge from the converter. Will report anything of interest when I do jump it. 
    2023 Tab 400
    2015 Audi Q7 TDI
    Northern Ohio

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    DenisPDenisP Member Posts: 542
    I received these pictures from WFCO support on the location of the jumper.
    2018 T@b 400, 200ah Lithium with Solar
    2013 Tundra TRD 5.7L
    Massachusetts
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    MuttonChopsMuttonChops Member Posts: 1,604
    If enough folks Ask for a Jumper . . .
    Maybe they will put a darn Switch back on the PCB. ;)
    '18 320 Spitched axle, 3020HE; PNW based
    TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
    Adventures:  51   Nights:  322  Towing Miles 41,200+
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    RobermcmRobermcm Member Posts: 84
    @DenisP, is that an 8955-ad or the 8755? I wanted to know how far apart it has to come to add the jumper. As in, can all the terminated wires to all parts of the trailer stay connected, or is there a fair amount of disconnecting necessary to get to it?  Thanks!
    2023 Tab 400
    2015 Audi Q7 TDI
    Northern Ohio

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    DenisPDenisP Member Posts: 542
    I spoke to Shaun yesterday about the green light issue with my WF-8955-ad. I asked for detailed pictures showing the location and orientation of the jumper placement. Shaun sent the pictures I posted earlier and he is sending the jumper which I will install once received. I will update my post once it is in place. 
    2018 T@b 400, 200ah Lithium with Solar
    2013 Tundra TRD 5.7L
    Massachusetts
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    RobermcmRobermcm Member Posts: 84
    one question i have is whether the nu_camp installed wiring between converter and battery is adequate to support the deep drain lithium charging amperage from this converter once it is indeed running at lithium levels. I’d think nu_camp would be all over that, but there was some chatter about the length of the runs of wiring and whether that was stopping the auto detect from staying at lithium. Over my head, but I’d not want to create unsafe levels of amperage. If my 40 amp battery disconnect breaker is up to installed charging wire amperage capacity, are they both less than the 8955 (as in 55a?) can supply?
    2023 Tab 400
    2015 Audi Q7 TDI
    Northern Ohio

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    DenisPDenisP Member Posts: 542
    I received the Jumper today and successfully installed it. The installation is quite straight forward actually.  Tools needed: a phillips screwdriver and a light. Make sure to turn off the 12 volt cutoff switch  Step one: remove the trim cover (two phillips screws).  Step two: remove the two screws holding the converter on lower front of the power center.  Step three: carefully slide the converter out and expose the back by turning it slightly toward the bed. Step four: locate the pins for the jumper shown in the picture from my previous post. Step five:insert the jumper as shown in the picture from my previous post.
    Step six: slide the converter back in place and secure withe the two screws.  Step seven: Turn on 12 volt power and check for blue light. Step eight: replace and secure the trim cover.
    Total time to complete the jumper insertion (converter to Lithium) 10 minutes
    2018 T@b 400, 200ah Lithium with Solar
    2013 Tundra TRD 5.7L
    Massachusetts
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    RobermcmRobermcm Member Posts: 84
    edited April 25
    I’m embarrassed to say that I don’t know what you mean by 12v cut-off switch. There’s a glaso 40a breaker that separates the wfco converter from the batteries. There’s the battery to 12v appliances twist switch. I’d have both those off as a matter of naive caution. Am I close?

    Thanks for the install details. Easier than I’d ever hoped!  Will try it soon. Love that blue light. 
    2023 Tab 400
    2015 Audi Q7 TDI
    Northern Ohio

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    DenisPDenisP Member Posts: 542
    The twist switch is what I called the cutoff switch.  You are being double safe which is always a good approach.  After completing the install, it was easier than I was anticipating.  Good luck, you should be fine.
    2018 T@b 400, 200ah Lithium with Solar
    2013 Tundra TRD 5.7L
    Massachusetts
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    WESDUNCANWESDUNCAN Member Posts: 5
    Thank you so much for sharing this information. I have my resistor and I'm going to try this tonight. I hope it doesn't back fire on me lol, we're camping and I have no plan B if it kills the inverter. 
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    WESDUNCANWESDUNCAN Member Posts: 5
    Success! Wow. I can't believe that worked.g
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    WESDUNCANWESDUNCAN Member Posts: 5
    Has anyone verified that this is actually working and not just turning the Li light blue? Lol!
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    RobermcmRobermcm Member Posts: 84
    edited May 3
    I did the resistor addition to my wfco 8955-AD just now. As @DenisP suggested in this thread, it’s a 10 minute job. I took a few additional midrange photos to give folks a little more perspective on what was done. Hope they help. Night light is now blue. Hoping it also charges like lithium batteries request, @WESDUNCAN

    Also,  i discovered on the six pin connector location, my pins #1 and #2 were fully touching, to no ill effect. Visible in the one picture. 


    2023 Tab 400
    2015 Audi Q7 TDI
    Northern Ohio

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    WESDUNCANWESDUNCAN Member Posts: 5
    I haven't verified voltages yet, but I'm able to stay on battery for more than a few seconds now with my refrigerator and water heater on. I couldn't do that before the resistor mod. I'm thinking my lithium battery was never charged enough before. Now my only concern is double checking the length and gauge of wires going from my battery to my inverter. I'm sure it's under sized like everything else in my camper. 
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    RobermcmRobermcm Member Posts: 84
    WESDUNCAN said:
    I haven't verified voltages yet, but I'm able to stay on battery for more than a few seconds now with my refrigerator and water heater on. I couldn't do that before the resistor mod. I'm thinking my lithium battery was never charged enough before. Now my only concern is double checking the length and gauge of wires going from my battery to my inverter. I'm sure it's under sized like everything else in my camper. 
    What you describe sounds like more of a problem than the converter only charging to 85%. 

    Do you have a shunt installed?  I just added one to my set up and it removes all the anxiety of what’s happening to my battery. Turn on the Victron app and look at the current draw, start up an appliance and what the current draw change. Net difference is the appliance you added. Solar does make it a little tricky, and it is adding to the amps number. But you could turn charging off for a minute, if the sun is varying a lot. Anyway, a shunt might help you see what’s pulling on your battery. 
    2023 Tab 400
    2015 Audi Q7 TDI
    Northern Ohio

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    WESDUNCANWESDUNCAN Member Posts: 5
    Robermcm said:
    WESDUNCAN said:
    I haven't verified voltages yet, but I'm able to stay on battery for more than a few seconds now with my refrigerator and water heater on. I couldn't do that before the resistor mod. I'm thinking my lithium battery was never charged enough before. Now my only concern is double checking the length and gauge of wires going from my battery to my inverter. I'm sure it's under sized like everything else in my camper. 
    What you describe sounds like more of a problem than the converter only charging to 85%. 

    Do you have a shunt installed?  I just added one to my set up and it removes all the anxiety of what’s happening to my battery. Turn on the Victron app and look at the current draw, start up an appliance and what the current draw change. Net difference is the appliance you added. Solar does make it a little tricky, and it is adding to the amps number. But you could turn charging off for a minute, if the sun is varying a lot. Anyway, a shunt might help you see what’s pulling on your battery. 
    Yeah that was my first instinct as well. My setup should work fine at 85%. So far it does seem to be working better for me now that my ac/DC converter is working in lithium mode. I have a simple setup, one lithium battery, no solar, no DC/AC inverter or anything like that. No shunt. I might have to look into that. 
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    KK1LKK1L Member Posts: 108
    edited May 13
    I have also added the 1kOhm between pins 1 & 2 (or 5 & 6 whichever they are numbered. They are labeled GND & SW...which is clearly ground and switch). After resetting by disconnecting the battery from the WFCO (battery disconnect switch) the LED went from green to blue and charging started. My shunt was claiming my battery was at 91% and with the LED green I was getting no current to the battery from the WFCO. When it switch to blue I was getting about 7A charge current and the battery eventually made it to 100% and no current.

    Poor picture. There is heat shrink on the resistor obscuring the color code as well.


    73 es God Bless de KK1L, Ron <><
    2023 T@B 400 Boondock "Running up a T@B"
    Jericho, VT
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    KK1LKK1L Member Posts: 108
    edited May 13
    Robermcm said:
    one question i have is whether the nu_camp installed wiring between converter and battery is adequate to support the deep drain lithium charging amperage from this converter once it is indeed running at lithium levels. I’d think nu_camp would be all over that, but there was some chatter about the length of the runs of wiring and whether that was stopping the auto detect from staying at lithium. Over my head, but I’d not want to create unsafe levels of amperage. If my 40 amp battery disconnect breaker is up to installed charging wire amperage capacity, are they both less than the 8955 (as in 55a?) can supply?
    Wire size determines its resistance over a given length and therefore the power dissipated over that same length for the current flowing. An 8ga wire is allowed to carry 55A in a THHN insulated wire (90degC allowed). The fusing should be 40A...which it is in the stock setup.  For anecdotal reference I have 200AH Lithium with a 50A breaker (GLOSO). With the batteries about 20% I drew about 52A charging current peak for maybe as much as 30 minutes which dramatically reduced over the next hours as the batteries charged. In a low charge situation with the stock 40A breaker will trip after a few minutes at 50ish Amps (working as designed to keep the 60degC limit). Being an electrical engineer by trade I am eyes wide open and personally okay with a short term 50A flow in the 8ga wiring, which is another way of saying I am not carte blanche recommending changing the breaker to 50A!

    Reportedly the WFCO is sensing a current draw of more than 20A to switch to Li mode. The 8ga wiring would not prevent that. I can attest (as would others) that the unit does indeed switch to Li in this case. The problem is it can and does revert to lead acid mode under some conditions. 

    My guess is there is an adjustment on the WFCO which would limit the 55A to less than that, but likely not something WFCO would let slip as the same adjustment would allow more than 55A and overstress the unit.


    73 es God Bless de KK1L, Ron <><
    2023 T@B 400 Boondock "Running up a T@B"
    Jericho, VT
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    RobermcmRobermcm Member Posts: 84
    Helpful and educational. Thanks much!
    2023 Tab 400
    2015 Audi Q7 TDI
    Northern Ohio

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