battery not charging on shore power & still being drawn down

franconiahiker · November 11

Hi all,

I am new here and have had a 2023 T@B 400 Boondock for about 6 months now. Very much appreciate all the information folks have posted here.

I have 2 – 12V 100 Ah lithium batteries and a Victron SmartShunt. Like other folks, I discovered that my WFCO 8955 AD was not detecting the lithium battery (LED is green) even when I drew the batteries down to 3% SOC and 12.15 V and then charged them on shore power. I was able to get the jumper from WFCO referred to in another thread but haven’t installed it yet because another problem came up.

I am currently plugged into shore power (not sure if it’s 15 or 20 A) to keep the T@B heated before we take it on one last outing for the year. Although I’ve charged the batteries on shore power at my house in the past, I noticed at one point the batteries weren’t charging, though the heat is working (as is the microwave and outlets that normally work only on shore power). Not only that, but any of the things that operate on battery power (lights, exhaust fans, USB chargers) are drawing power from the battery (I can see the additional amps being drawn on the Victron SmartShunt app) even though I’m plugged into shore power.

I’ve tried to unplug, wait a few hours and plug back in shore power, turn on and off the battery disconnect, and turned on and off the 40 A battery circuit breaker. Initially, one of those or some combination worked for a while (1x), but now back to not being able to charge the battery and it being drawn down by lights, etc. (as described above). A repeat of unplug, plug back in, etc., had no effect.

Any suggestions would be appreciated!

pthomas745 · November 11

Welcome! Can you show us your:Victron status and history screens?

Have you made sure: the inverter is off? If you have "battery heaters" or "heated tanks" are they off?

Are you sure there is actually power coming from the home circuit? Looked at each of the circuit breakers in the WFCO (if you have the WFCO and not the Multiplus).

Have you taken your battery readings with a stable battery? Trailer unplugged, battery switch off? Trying to chase voltage/amps with a battery in use can be a roller coaster.

And: show us the settings you have for the Victron shunt. The shunt, since it "counts" the battery amps "used", will be your go-to device to determine your battery status. That section of the app will give you a clearer picture, but....if it is not set up properly, it can also mislead you quite a lot. We have seen a lot of trailers with the Shunt and Solar controllers not properly set up.

Grumpy_G · November 11

The OP already stated the outlets in the trailer do work. A quick test is to turn off the battery switch, if the lights go out then the converter is not working for some reason. Also toggle all the breakers off and on. Then start checking the wiring.

franconiahiker · November 11

Hi all. Thanks for your responses.

I had previously checked inverter and battery heaters, both off. Also had checked all circuit breakers by flipping them off and back on. Definitely power coming from shore power. I am sure that all the features that normally operate on battery are still operating on battery with shore power plugged in as I can see the increase in amps being drawn on the Victron app when I use one of those features, then turn it back off.
When I turned the battery switch off, the lights go out for a second or two, then come on (presumably they find the shore power), and the amp draw on the battery decreases by a couple of amps (what I'd expect for those particular lights). But when I turn the battery switch back on again, I can see the amp draw go back up by same amount.

Not sure this will help, but below are the screen shots of the status and history from earlier today. Not, I'm getting around 2.5 amps from the solar at the time (2 A shown on screen and is drawing 0.5A). On the history, you can see I discharged the battery down to around 12.1V and charged it on shore power (house) in mid-October. Despite it being a slow charge (AD getting a lead-acid battery), it did charge the battery up to around 99%.

At a loss...

Image: https://us.v-cdn.net/5021717/uploads/editor/9x/pgr0jyd5w4w8.png

Image: https://us.v-cdn.net/5021717/uploads/editor/g5/ynwf989a13u5.png

MuttonChops · November 11

franconiahiker said:
. . . When I turned the battery switch off, the lights go out for a second or two,
then come on (presumably they find the shore power),

. . . getting around 2.5 amps from the solar at the time (2 A shown on screen and is drawing 0.5A).

I'm wondering if the Power Center Convertor is sick vs failing.
When the Battery Switch is set to OFF there should be no 'lights go off for a few seconds' event.
A fully normal Convertor will be providing >= 12.x Volts all the time on shore power if it's Circuit Breaker is on. Having the Battery Switch Off or On normally only changes whether the Battery is being charged or not. There is no switch/smarts in the convertor to cause it to stop/start generating 12VDC.

For me (not a Victron expert) the Status Screens are not remarkable . . . that is 2Amps is flowing into the Battery, the positive 27W shown. Now if the Convertor is sick that could be the solar, if the Convertor is OK then the Convertor is at a very low charging current. The displayed Battery Voltage also seems low for a fully healthy convertor.

Consider:
++ Confirm Inverter (if installed) is fully off or in ACV available mode.
++ Alde 120VAC heaters draw 950W each, combination of Adle heater(s), Inverter, other trailer ACV loads may be taking
the lions share of Power Center capacity . . . causing lower Convertor output.

++ Redo your measuring/observations with everything possible turned off . . . are you seeing what you think you are seeing.
++ Install the Li-Ion Jumper before starting your Redo Measurements

Yoshi_TAB · November 11

Hi,

I don't have an answer, but have the exact same issue. Since I moved over to 2 x 105 Ah lithium batteries, my batteries will also drain while on shore power down to a low level. My issue is, my lead acid WFCO is not going into charge mode. Everything else about the WFCO works fine. My WFCO powers the 12V items fine (as it should) while on shore power (even with the battery switch off) and will occasionaly go into charge mode. In fact, it will charge my lithium batteries to 100%. although very slow.

I've contacted WFCO and have posted on a few other RV electrical forums and get a variety of answers to why. Many complaints about the "quirkyness" of WFCOs compared to other brands.

Here is my theory. A fully charged lead acid battery is in the 12.6-12.8 V range. But a lithium battery still has a voltage of about 12.8-12.9V at a 17-20 % SOC. So a low SOC lithium battery is still above the voltage of a fully charged lead acid battery , so the circuit/algorithm does not detect that charging is necessary (if it thinks it's attached to a lead acid battery..as in your case).

I have since moved over to a standalone victron IP 22 charger hard wired into my battery circuit so I don't worry about it anymore.

Hopefully other will chime in..don't know if my theory is right, but this has also stumped me and have not been able chase down the reason.

Grumpy_G · November 11

Agree with @MuttonChops , something ain't right. Either the converter itself is going out or there is a bad connection from the converter to the trailer.

@Yoshi_TAB , your thinking is along the right path. However the converter doesn't use voltage but time to change its output voltage. The converter starts with 14.4V if the battery is drawing a lot of current as this indicates a fairly discharged battery. After 4 hours it ramps down to 13.6V, and after 48 hrs it goes to float mode at 13.2V (These numbers are from the WFCO converter manual). The problem is that a LiFePo battery likes to see 14.2V or more at the end of the charge cycle to fully charge and balance the cells. If you ever watched one of Will Prowse's videos you'll notice he uses a lab power supply and not a fancy charger. A LiFePo battery with BMS is happy with constant charging voltage, the BMS is basically a cell by cell charge controller.

franconiahiker · November 12

@MuttonChops, yes, if on shore power, and the battery disconnect is turned off, it shouldn't affect the lights. But...everything that is normally powered by the battery when there is no shore power is still powered by the battery when there is shore power, and at the same time, the Alde heat, microwave and shore power outlets are on shore power. Really odd, but I'm pretty sure I've confirmed that by watching the current increase on the Victron app as soon as I turn on the lights, fan, or use a USB port.

The current on the screen shots is the solar. I can confirm that on the SmartSolar screen which shows how much current is going to the battery. The WFCO is not charging the battery at all even though it has in the past so I'm familiar with that behavior.
Very much appreciate the suggestions, and maybe I should install the jumper. I was hoping to solve this first since the converter has charged the battery in the past.

mona · November 14

Could it be, that the outlet that you are plugged into, be the source of the problem?

MuttonChops · November 14

How about - - - - -

a] Power flows from the high potential to the low potential.
b] Battery is not fully charged due to WFCO in lead-acid mode,
     Solar is active, Solar Controller sees battery is not fully charged
     so Controller is sourcing 14.4V to battery
c]   Power Center Convertor is in typical power mode, outputs 13.6V
d] Battery potential is above Convertor potential.

e]   Battery cut-off Switch is Open.
      Convertor is only power source for trailer loads.
      Current flows from Convertor

f]   Battery cut-off Switch is Closed.
     Both Convertor and Battery are connected to trailer DC Bus loads.
     Battery becomes the power source due to high voltage potential,
     current flows from battery as reported by Victron Shunt

rfuss928 · November 14

MuttonChops Very nice description and diagram. I completely agree...
My experience with a WFCO not switching to Li was the charging was extremely slow. Many days to move 2 x 100 AH LiFePO4 batteries from 50% toward ~80%. It may get to 13.8v for a short while after power up which might drive a little charging current in a deeply depleted Li battery. But then it quickly switches to 13.2v (PbA float voltage) which has no potential to drive Li charging current.
It's very hard to diagnose system problems when you know one component is operating improperly. IMO - Most of the electrical issues of the OP will be solved when the Li jumper is installed in the converter.

franconiahiker · November 16

@MuttonChops, great diagram. I think I will print it and put it up in the situation room! So, that's an interesting theory, and seems to make sense. I'm assuming the "battery cut-off" is part of the converter circuitry. As an update, I unplugged from shore power yesterday for several hours. Before I plugged back in, I also turned off, then on, the battery disconnect. After I plugged back in to shore power, battery started charging! This morning, battery at 100%, no draw down. Then this afternoon, battery at 99% and being drawn down again. At any rate, your explanation makes the most sense to date.

@rfuss928, still haven't installed jumper. Was hoping to get other issues sorted first. Taking out the T@B for a few days soon, and will install after that. And yes, hoping that will do it.

In general, seems like the WFCO converters can be rather quirky.

rfuss928 · November 16

franconiahiker said:

@rfuss928, still haven't installed jumper. Was hoping to get other issues sorted first. Taking out the T@B for a few days soon, and will install after that. And yes, hoping that will do it.

It's difficult to sort out charging system issues when you know the primary component is malfunctioning. Very limited diagnostic measurements (independent volts, amps, charger...) from individual components just compounds the confusion. Other forum threads indicate the jumper installation in the 8955 is quick and easy. IMO - Fixing the know issue is the first priority in determining if there are any other issues and enjoying the benefits of your new batteries.

MuttonChops · November 16

franconiahiker said:
. . . I'm assuming the "battery cut-off" is part of the converter circuitry.

No. 'battery cut-off" is the stand alone Battery Disconnect Switch.

franconiahiker said:
. . . still haven't installed jumper. Was hoping to get other issues sorted first.

Highly recommend installing Convertor Jumper before your trip or any additional investigation.
The 'auto-detect' of the convertor is not dependable and causes odd/confusing observation issues.

franconiahiker · November 18

Thanks for the clarification regarding the battery cut-off switch.

Still probably won't get a chance to install the jumper before I leave, but appreciate the feedback...will stop trying to figure it out until I see how things behave post jumper install. At least I've now got the battery to 100% and can leave the disconnect switch open so that it stays charged on solar until we leave, then boondocking.

GregR · November 20

In trying to be proactive before I switch out my AGM batteries for a lithium battery, I contacted WFCO trying to get a jumper. Here is WFCO's response:

"The jumper is not a requirement to use your auto detect, it is more of a last resort. the install of the converter will play a part in the auto detect functioning correctly; in most cases it works just fine.

Check the size of your inline fuse and make sure it is a 60amp fuse.

Then you need to allow the converter the time to detect the battery. If you have any external chargers or solar you will want to disable these during the detection stage. Drain your lithium batteries down to 10-20% and then plug into shore allowing the converter to charge the battery back to full; towards the end of the charge cycle you will see the green LED change to a blue LED indicating the lithium charge mode."

So, is it how nuCamp initially wires the trailer? Is it the 50A inline fuse (or maybe the 40A circuit breaker) that causes the auto-detect issue?

MuttonChops · November 20

@GregR; Thanks for posting the WFCO Response.

If nuCamp is installing the 40A/50A components on factory Li-Ion rigs that could be a system performance issue. For trailers without factory Li-ion . . . dealer installed new owner battery choice or post sale DIY . . . then the dealer or DIY-person should be upgrading the 40A/50A items to handle the higher charging current spikes.

However, based on WFCO Auto-Detect Discussions on several RV Forums those components are
not the only Auto-Detect 'bug' as other forums have noted:
- - - WFCO distance from Battery,
- - - Wire sizes between WFCO and Battery
As factors for correct battery type detection.

WACO has not been as clear/detailed on the Auto-Detect Operation as most of us would like. For example does it store the Li-Ion detected for future usage or must the Li-Ion be drained to <20% capacity every time to insure full re-charge via the Convertor only?

What are WFCO installation specifications for wire size and distance for correct battery type detection?

Even if WFCO will no longer provide the Resistor Plug-In, that is an easy item to create for a DIY-person. I for one would install the resistor . . . . as I don't trust Automatic when the operation conditions are not fully explained.

GregR · 1:19AM

But nuCamp is installing a Power Center with auto-detect that won't necessarily work because they fail to install the other appropriate components for the auto-detect feature to work properly. It seems reasonable to me that the Power Center should work as designed without the need for modifications to the system - especially when neither nuCamp nor WFCO have any mention of the possibility that modifications may be required.

Installing the appropriate components and even changing the wire size to the battery isn't that big of a deal, it's the lack of documentation about those modifications and that they need to be done that's annoying. It's interesting that the WFCO Operator's Manual includes instructions on how to replace the entire converter section.

However, the whole lack of transparency for the DIY-person could be simply to require the modifications to be done at an authorized service center...

WFCO didn't say they wouldn't send me a jumper, they just sent me the response I posted. I'm still going to reply to their email and ask for one anyways.

elbolillo · 2:21AM

GregR said:

In trying to be proactive before I switch out my AGM batteries for a lithium battery, I contacted WFCO trying to get a jumper. Here is WFCO's response:
"The jumper is not a requirement to use your auto detect, it is more of a last resort. the install of the converter will play a part in the auto detect functioning correctly; in most cases it works just fine.

Check the size of your inline fuse and make sure it is a 60amp fuse.

Then you need to allow the converter the time to detect the battery. If you have any external chargers or solar you will want to disable these during the detection stage. Drain your lithium batteries down to 10-20% and then plug into shore allowing the converter to charge the battery back to full; towards the end of the charge cycle you will see the green LED change to a blue LED indicating the lithium charge mode."
So, is it how nuCamp initially wires the trailer? Is it the 50A inline fuse (or maybe the 40A circuit breaker) that causes the auto-detect issue?

There is no reason that someone should have to go through so many hoops for the WFCO converter to work. These units should have a dedicated switch to change the battery charging profile. Charge a bit more and make these units work correctly. There isn’t any good reason that there should be so many difficulties with these converters.

Sharon_is_SAM · 11:27AM

We will have a lithium battery placed in our CSS in the spring by nuCamp. Not sure the 8955 will fit or not, but, this is the info we received from the shop.

“The WF-8955-AD-WAGO Converter with Auto Detect is designed to work with both AGM and Lithium Batteries. When replacing the single AGM battery with a Lithium battery this converter will identify the lithium battery and function automatically. Here is a link to the vendor website regarding the converter and its specs. https://www.wfcotech.com/shop/power-centers/wf-8900-ad-series-power-centers/wf-8955-power-center-2/

We would run 2/0 wiring from the battery. We would run 4g red & white. The length or wiring is dependent on the location of the battery install. Options are in the tongue box or under the bed. Typically they are installed under the bed.”

So, maybe they have learned the OEM smaller wiring was a factor in the AD not working?

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