Lithium Battery Monitoring Conundrum

gfreid09 · September 2022

I posted this issue on the NuCamp Facebook group and, despite all their expertise, they are stumped. My apologies if you’ve seen this there. I’m hoping someone might have a solution.

We picked up our 2023 T@B 400 about a week ago. On the advice of several of you, we've parked the rig (yet-to-be-named) in our driveway and have spent the past week getting to know it's various systems. We love it and are looking forward to our first trip in a week or so. I have an electrical issue I've not been able to figure out. Mostly, I've left the rig unplugged from shore power. The days have been sunny and the solar panel has kept the lithium battery fully charged. In the evening I shut everything off except the isotherm fridge; I've left the battery on. In the morning the battery seems to be dead - no fridge, no lights, nothing. The battery monitor inside the door doesn't even register. When I plug into shore power, everything powers up immediately, the battery charge monitor reads full, and the voltage reading on the Victron app reads 13+ (solar) and 13+ (battery).

A quick note to add that might help sort through this issue. I disconnected from shore power very soon after everything powered up and the battery read as fully charged. Once disconnected, the electrical system works fine and battery still reads as fully charged. So, it appears the battery remained charged overnight, it just didn't read that way in the morning. Plugging into shore power seems to have re-set the system in some way and then fully charged battery reads that way.

Does anyone have an idea about what's going on here and how to address it? Thanks!

(Title edited for search purposes. Moderator)

techietab · September 2022

You can't really trust the Victron solar charger or on board power for an accurate measurement of battery voltage. Have you checked the battery with a multimeter when it's in the 'dead' state? (Ideally, disconnect everything from the battery, wait 15 minutes, then take a voltage reading). If so, what does it read?

Also - what kind of battery are you using and what are the specs? If it's a LiFePO4 type, I'm wondering if you're somehow tripping a failsafe on the onboard BMS system.

stp2136 · September 2022

The onboard NuCamp battery monitor is only kinda good for lead acid or agm batteries. Lithiums run a volt or so higher so they always indicate charging or fully charged no matter their state. Furthermore the WFCO WF 8700 AD converter chargers don't automatically recognize Lithium batteries except by "tricking" them so it doesn't properly charge them--the default charge profile is for LA or AGM. See posts below. The best you can do is to leave the charger on for several days prior to your trip and it will bring the lithium up to 90% or so.
The Victron solar control will top it off if you have sun and will give correct voltage readings but you need to have all loads off to get a battery rest reading. If you want to know exactly what the battery charge condition is you can get a Victron smart shunt.

Denny16 · September 2022

First off, the OP has a new 2023 TaB400 with the Battleborn 100 amp lithium battery and Victron SmartShunt monitor along with the solar setup. The monitors should be set for lithium, and the SmartShunt is accurate with its readings. To get a rested reading, turn off so,are charging on the Victron App solar controller setting menu, then turn off the battery disconnect, shore power disconnected, wait the 10-20min, and take a reading.

@gfreid09, which battery option did you get, the single battery or? Did you include the Victron package with the 3K Inverter system or?

Since this is a new camper, you should contact your dealer and nüCamp customer support. This is a new battery/electrical system, with different nüCamp provided components from what most of us here have. That said, the new larger DC fridge will not completely discharge a 100 amp lithium battery in 24 hrs, let alone just overnight. You seem to have a new issue here, and nüCamp needs to be contacted to sort this out.

Depending on the options purchased, the larger Victron 3K inverter also charges the battery bank, not the WFCO power converter, which may or may not be the same models used in 2022 or earlier models of the TaB400. Other than the obvious things, like turning the inverter off or on (make sure it is off when not being used), the battery 30-amp circuit breaker next to the battery cut off switch is not tripped, and the circuit breakers/fuses are not tripped or blown, there isn’t much else to check.
Cheers

gfreid09 · September 2022

Thank you all for these responses. Didn’t realize the Victron app might be so unreliable; it is set for the lithium battery set up. The battery is a Battle Born BB10012.

I have done as suggested and turned off all systems and taken a battery reading. The Victron battery reading is 13.22 volts and current is 0 amps.

I have contacted NuCamp about this. Not yet heard back.

webers3 · September 2022

techietab said:

You can't really trust the Victron solar charger or on board power for an accurate measurement of battery voltage.

Hmmm.....

Denny16 · September 2022

Whilst the battery is connected to the solar or shore power, any battery monitor reading is going to show the charge voltage going to the battery, and not necessarily the actual battery voltage level. Shutting off the solar charge on the Victron App, will disconnect the solar panel from the battery, and turning off the battery switch will kill any trailer loads on the battery, then the Victron SmartShunt monitor should show the correct battery voltage level.

Seems gfreid has a single 100-amp Batrleborn lithium battery. Not sure if a Victron battery monitor like the SmatShunt is included? Again, this is a new setup from nüCamp, and their website has not been updated for the 2023 model TaBs.

Cheers

gfreid09 · September 2022

Denny16 Since it is evening now the solar is not charging. I shut the battery off an hour and it seems (according to the VictronConnect app) hold steady at 13.22 volts. I was worried that it might not be holding a charge, so I'm going to monitor that later and check again in the AM.

pthomas745 · September 2022

The Victron app connected to the batteries, with the battery switch off, is as good as a multimeter. I know we dance around about the "best" way to monitor, but the Victron can hold its own as a decent voltmeter.

Grumpy_G · September 2022

The OP might be misled by the battery voltage reading. LiFePo4 batteries have comparatively little voltage drop vs state of charge, unlike lead acid batteries. Between the power consumption of the Isotherm fridge and the never ideal recharge from the solar panel I'd think the battery is hovering around the lower end of the capacity. During the day the solar panel keeps the battery charged enough to make up for the fridge draw but at night the battery gets drained.

Charge the battery via shore power for 24hrs and things should work for a few days.

Sharon_is_SAM · September 2022

@gfreid09 - from Battleborn regarding monitoring of Lithium batteries:

” …lithium batteries do not experience a significant voltage drop as they drain. Without a battery monitor, there is no warning your batteries are dying until they are dead and the BMS (Battleborn built in battery monitor) shuts them off.”

Here is the link: https://battlebornbatteries.com/what-is-a-battery-monitor/

Basically, you need the Victron shunted battery monitor.

techietab · September 2022

13.22v on a Battleborn 100Ah should be somewhere in the mid-70s percentile for remaining capacity, which based on my experience should be enough to get the stock systems (and then some) through the night without draining the battery to the point that the BMS trips and shuts the output off.

As others have suggested, a Victron Smart Shunt would be especially helpful for charting your battery's behavior and identifying potentially problematic loads that are draining it faster than expected.

Also - is it possible that you have the refrigerator set to the coldest temp range without anything inside? This is a worst case scenario for power consumption.

gfreid09 · September 2022

Thank you all for this information and helpful suggestions. I will check into the shunted battery monitor and I will charge the battery via shore power for a solid 24 hours. On the fridge - yes, it was empty and the cold setting was pretty high. Did not know this about keeping the fridge cold but it makes sense. Perhaps that was part of the issue. When I recharge and set to run the system off the battery I will try leaving the fridge off or at least at a very low setting.

ckjs · September 2022

@gfreid09: Could the inverter have been left on overnight? Typically they are connected directly to the battery & shunt, beyond the “reach” of the disconnect switch.

pthomas745 · September 2022

Lithium voltage "capacities" drop so slowly that it seems it is not as easy to get good info from the battery voltage. Still useful....but once you hit the lower range, it drops off a cliff. With a rested lead acid battery, you could get a "decent" idea of status. But, with a lithium...if it reads 13.2..does this mean it is closer to 70 percent capacity or 30 percent? Hence....the shunt is the better tool.

Denny16 · September 2022

At 13.2VdC you have used 30% and have 70% of battery capacity remaining.
as for the DC Norcold fridge, setting it to “3” is a good starting point, and get a fridge thermometer to determine the fridge temp, which should be between 35-40F. Setting it to max cold, will make the fridge cycle more often and turn it into a freezer, which might not be good for the plastic liner?
Cheers

gfreid09 · September 2022

Thanks for the additional info and questions. Didn’t know that the inverter might be a possible issue here. Under what circumstances should I turn the inverter on or off?

VictoriaP · September 2022

@gfreid09 The inverter should always be off unless actively needed. If you’re plugged in, it isn’t needed. If you’re boondocking, it’s only necessary while you’re using something that requires a household plug (110v, not 12v).

Hanktheyank · September 2022

I’ve been using a Battleborn 100 AH battery in a different, but electrically similar, setup and have experienced the same problem as the OP in this thread — battery has had plenty of time to fully charge, the Victron meter shows 13.1 or .2 while also indicating “fully charged”, but power output seems stuck at well below 50%.

I recently traded up from a 2018 400 to a 2022 400BD, and have made two and a half coast-to-coast round trips in the past year (45 nights aboard, 16K miles}. The Battleborn rides in our Ram TV and powers a Dometic chest fridge to supplement the 400’s small fridge. The plan was to use battery power by day, then shore power overnight to run the Dometic as well as a 25 amp Victron charger for the Battleborn. My setup includes the Victron shunt and meter.

After a few daily cycles and overnight rechargings, the battery refused to go above that 13.2 volt reading.
Upon arrival, I gave it a full 24 hours of charging without the Dometic connected, but still couldn’t get past 13.2, far below the desired 14.6.

I’ve now spoken to Battleborn tech support, which is excellent at getting back to you and working through the problem. They confirmed my low voltage, authorized a warranty return to evaluate the battery and its control board, and sent me a packaging kit so that Fed Ex could legally transport it. (Good luck if you need support on a $300 no-name).

The tech suggested that a cell or two may have “gotten out of balance” and the BMS (battery management system) is preventing full charging as a result.

My take away from all this is that Lithium offers great advantages, but is still a complex developing technology. Great that NuCamp is offering it, and likely it will be standard in just a few years, like LEDs. But there are still mysteries. So if you need further help, try Battleborn.

Sharon_is_SAM · September 2022

Good to know! @gfreid09 - you may need a tune up!

gfreid09 · September 2022

Thanks for sharing your experience about the Battle Born battery. I've contacted NuCamp and they have advised me to be sure the inverter is turned off. I am away, so I can get to that until the weekend. I have to say, this has been more than a little discouraging. We've owned the 400 just a week and I'm reluctant to take it out until this battery/electrical system issue is resolved. I'm hoping the problems I'm experiencing are mostly the result of my inexperience that they will be addressed as I learn more about my 400.

qhumberd · September 2022

Try not to get discouraged. There is a lot to learn when you first get the trailer and you cannot know it all on day 1. It is a good unit and made very well so as you learn how to use the systems its gets easier. And the support here on the forum is great and has helped me many times. You will love the 400 once the new owner anxiety settles!

qhumberd · September 2022

BTW the fact that NuCamp went with Battleborn rather than the multiple other choices in the Lithium battery space is testament that they want quality and support for their units. More expensive to use Battleborn, but you kinda get what you pay for unless you know the tech well.

AldebaranJill · September 2022

If you don’t trust the stock charger to fully charge Battleborn, consider adding Victron Smart 15A Charger. Fully programmable via bluetooth via app. Support from Battleborn and Victron were excellent to determine settings. Very happy with mine.

VictoriaP · September 2022

@AldebaranJill Nice find, Jill! Did you mount that charger in the tub or are you using it as a portable?

AldebaranJill · September 2022

VictoriaP said:

@AldebaranJill Nice find, Jill! Did you mount that charger in the tub or are you using it as a portable?

Yes this was a VERY nice find - I knew it was coming out and at first they only had euro versions but I kept waiting. It has been a superb solution to the WFCO issue without needing to replace the WFCO. Very affordable.

I have mine mounted inside under the fridge horizontally. I have the wires that charge snaked thru the bottom vent under fridge. And I plug it into the outlet above my sink. For me, I use it to charge when on shore power before trips, so permanent mounting made sense. I like to see the lights ☺️

I have yet to see anyone else mention this as a solution to fully charging ANY battery that is very portable and doesnt necessitate another charger/converter installation to replace WFCO so wanted to let others know this is an option. Being able to control charging profiles via my phone has been tremendous.
J

WayneW · September 2022

+1 on the Victron charger. We have the 10a version. I put an SAE plug on the end so I can just plug into the SAE connection that I installed for a portable solar suitcase. I also take the alligator clips just in case someone else needs to use it. I can let the factory WFCO partially charge my Ampertime 100 ahr battery and finish it off w the Victron charger or just use the Victron straight away. Or the rooftop solar and/or the portable panel. It’s nice to have options.

Denny16 · September 2022

Yes, yes it is Wayne. I also like the VictronConnect apps, and how their various components can be connected to work together. The new 400-amp lithium package for the 2023 TaB400 includes a Bictron Inverter/charger that is used to charge the lithium bank, instead of the WFCO charger. The 3K watt inverter also powers all the TaB’s AC outlets. Nice setup. This portable charger is a nice alternative for those of us who have smaller battery setups.
Cheers

rcuomo · September 2022

I’m using the DC Home app to monitor my Renogy battery. No sure if the app is compatible with other LiFePO4 batteries.

ChanW · October 2022

That Victron looks great @AldebaranJill , thanks for that!

I wonder how the charge-curve, and battery maintenance capability of it, compares to the Noco Genius.
Per Noco, the Genius' de-sulfation cycle is effective at avoiding needing to 'recondition'. I'd love to see a comparison of that to the Victron's 'reconditioning' and 'storage' modes.

Edit:
Ok, you got me looking into it...
It seems that the Noco Gen1 that I've been using, lacks any kind of equalization mode (should have known that), although it does tout its de-sulfation charging cycle capability.
ie: The only way I'd be able to run an equalization cycle, in this case, would be on a nice sunny day using my solar panels.

But my question now is, is equalization important, if the battery is already being properly desulfated? Any knowledgeable battery chemists? 🤔

I'm liking this Victron, because of the equalizing function... It doesn't depend on the sun (or lack of!)

(Oops, sorry, off topic! You lucky lithium battery owners don't need to worry about such things! But this Victron charger offers an easy path for an upgrade to lithium for me! One more justification for a cool new smart-charger!)

AldebaranJill said:

If you don’t trust the stock charger to fully charge Battleborn, consider adding Victron Smart 15A Charger. Fully programmable via bluetooth via app. Support from Battleborn and Victron were excellent to determine settings. Very happy with mine.

Horigan · October 2022

The only downside to that charger is the relatively low charge rate of 15A. If you ever plan to charge your battery with a generator connected to shore power, that could take a while to charge the battery. If you're plugged into shore power at a campsite, then no worries.

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