When to pull my Lithium ion battery? How cold is too cold?

ragtag2

We have a 2024 T@G 5 wide Boondock in Seattle which is stored outside (with a cover) but no shore power connection. There is the little battery heater switch, but if I don't have shore power this is not going to be helpful, right? Should I pull the battery during our Pacific Northwest "winter" season?

Some backstory... just retrieved our trailer from the dealer where it sat for about 2.5 months(!) getting some warranty work (replacement belly pan/skid plate, faulty blinds and emergency brake cable replacement.) Victron app shows battery at 100% and had 13+ volts...  

Any insights would be greatly appreciated.

JamesDow

 
A lithium battery should not be damaged by being in covered Seattle winter weather, if not being used or charged.
I personally would not remove.
As an added measure of safety, most/many lithium batteries have a BMS (battery management system) that has low temperature protection.
The BMS protects the battery cells from damage.
If the battery has the ability to be put in a storage or standby mode, I would suggest that. It is suggested that the battery be stored at around 50% state of charge for optimal battery lifespan.
Removing the battery could be the best for battery life, but that involves risks also (accidental shorting, dropping, etc)
By the way the battery heater is very likely powered by the battery itself.
 
 Bottom line, it is your call.
 

The_Rigger

I take my LiFePo4 battery out when I put the camper to sleep in November, but my winters here in mid-Michigan are a lot more hostile than yours are in the Pacific North-Wet. You should be okay to leave it unless the temps get down closer to zero

Sharon_is_SAM

What about making sure any solar connection is discontinued to avoid inadvertent charging?

ragtag2

Thanks for your thoughtful input @JamesDow, @The_Rigger, @Sharon_is_SAM, you reliably offer spot-on and prolific entries and perspectives for us newbies and less experienced users. Know you insights are sincerely appreciated!

So, now I need to figure out which in-line fuse to pull at the battery in order to disconnect the solar panel...  Unless the solar panel, being covered by the trailer cover, would not generate input...  So many little rabbit holes to go exploring. 

Sharon_is_SAM

There has been discussion over on the Tab forum that indicates Victron recommends disconnecting solar from the controller. Simply turning off the controller, for some reason is not good enough. I speculate that in the event, the controller switch failed. You would end up charging when you shouldn’t.

ragtag2

So, all I really need to do is figure out which wire at the Victron controller is the solar input? (and disconnect that one...) 

Any suggestions where to go to proceed on that? (YouTube video, or even some photos of what I'm looking for?) The NuCamp manual does not include a wiring diagram... 

Sharon_is_SAM

@ragtag2 - https://tab-rv.vanillacommunity.com/discussion/18897/lithium-battery-ok-to-leave-in-camper-over-winter/p1

Here is the thread from the TaB forum.  Read through it and you will find that someone actually contacted Victron and reported that you should pull the fuse on the positive wire of the controller.  

The_Rigger

Why not just disconnect the negative battery cable? That'll pretty much guarantee nothing gets charged by the solar panel

ragtag2

@Sharon_is_SAM, that T@B forum was great reading material. Thanks for posting the link. I made it to there independently but got sucked into too many "interesting reads" without finding your linked thread. Among other things it solidified my smugness in having chosen a T@G and embracing the more minimalist approach to "living the dream."  If batteries need removing, I only have one... Not stressing about heat system antifreeze replacement/leaking is OK with me also. 

But, I digress, I'll be draining the battery a little and then disconnecting those leads (negative first!) from the battery in the next day or so. 

Thanks one and All for your continued support and sharing of expertise.

ragtag2

The saga continues!

I called the dealer where I bought the T@G and the service manager said to pull the battery, take it home and put it on a battery minder (set for Lithium) until next use. 

So, I drove to the trailer storage place and pulled the battery. Fate would have it that was a good thing because the plywood shelf I made to protect the battery/terminals was starting to delaminate. That tub is one harsh climate in there!

I then called BattleBorn tech support (mostly to ask what kind/size battery minder they would recommend.)  The response was, for Seattle, leave it in the trailer (100% charge is OK,) but disconnected (and NO battery minder even if you do bring the battery home.) Also, don't worry about the battery as long as it is showing at least 13v, preferably 13.3v. The Tech Person lives and winter camps regularly in Eastern Oregon... 

So, I'm not going to worry about this again until next winter. Instead, making battery shelf/protector from 1/2" MDPE lab bench scraps and an old cutting board. 

Sharon_is_SAM

Unlike lead acid batteries that require a full charge before storing, lithiums are best stored with a limited charge (50-70%).  Battleborn is the only brand that I know that says it is okay to fully charge and then store.  Maybe they assume the self discharge will drop the SOC to a level that will better preserve longevity.  ?

ragtag2

@Sharon_is_SAM I think your last sentence was addressed by the tech when he stated to expect 2-3% drop per month(!) and that (check the BattleBorn website guidelines) storage disconnected should be fine for -10 F. I'm not expecting that any time soon, here in Seattle. 

Never-the-less, that tub in front of the trailer is indeed one harsh climate for plywood. Here is my little shelf/battery protector made of 3/4" plywood, installed in May of 2024 and looking the worse for the wear in February of 2025. Note the mildew and delamination at the bottom of the plywood.
 
My replacement strategy is to use 1/2" MDPE (weatherproof?) lab bench scraps and an old cutting board...

Can't wait to get some better weather and go chasing the bucket list of places to visit in the SouthWest...  

Sharon_is_SAM

Good use of an old cutting board!