Lithium Battery…Ok to Leave in Camper Over Winter

manyman297

I’m getting conflicting advice on whether or not to leave my Lithium batteries in our camper over winter or bring them inside to a warmer climate. 

It can get down to single digit temps at times where I live but many are saying you can leave the lithium batteries in place and just make sure they don’t receive a charge. 

Does anybody have any insight?

AnOldUR

Depends on the battery manufacturer. Most of today's LiFePO4's have a BMS that will shut down charging below freezing. To that point, you can draw power from a lithium battery below freezing, but charging at those temperatures is what can damage the battery. You always have the option to turn the battery switch off and turn off solar charging in the app during storage.

Horigan

Unless it will be at single digits for three to four months straight, you should be okay leaving them out, disconnected.  Several brief excursions to single digits is be okay.  That's how my winter will be and I'm leaving them in.  

From Google:

• Less than 30 days: Store between -20°C and 60°C (-4°F and 140°F)
• 30 to 90 days: Store between -10°C and 35°C (14°F and 95°F)
• More than 90 days: Store between 15°C and 35°C (59°F and 95°F)

manyman297

Thanks for the info! Looks like I should be ok. My batteries don’t have a built in shutoff but I can just turn off solar charging and the battery disconnect. Glad to hear I won’t have to pull them out from under the bed.

BillCB

I have the same concern. I can apply the battery disconnect, but how do I turn off solar charging? Through the Victron app maybe - or a circuit breaker? (2024 T@B 400) 

SLJ

I leave mine in. They have a built in low temp cut off. I also have the Victron battery monitor that cuts off the Victron solar controller and the Victron Smart Charger if they're left on. Redundant as I also put a disconnect switch on the batteries that cuts everything off. Never know when you might need it due to a weather emergency so it stays ready to use.

pthomas745

@Billcb On the "SmartSolar" part of the app, on the Settings page, there is a "Charger Enabled" toggle switch. Just toggle it "off".

bjn2

@BillCB I've seen warnings not to leave the Victron solar controller in the off mode for extended periods. I"ve seen recommendations to instead disconnect the solar panel connections to the controller long term, but if you cover the trailer, you won't get solar power anyway. I have a second Victron controller on my trailer for an external solar port, but there's no incoming power to it unless I connect a portable solar panel.

It's best for battery life to store the lithium battery at 80% charge or a little less. I do cold weather camping and although my battery doesn't have a heater, it's inside and I can warm it up and charge it using shore power before heading out. 

AnOldUR

From Battle Born ...

Horigan

I'm surprised they suggest removing the positive cable as an option.  Typically you remove the negative cable to eliminate the risk of shorting your wrench on a ground.  Less likely on a trailer verses a car.

manyman297

@bjn2 What’s the reasoning for not using the on/off function on the MPTT? I was hoping I could just turn the charge off and not have to deal with physically disconnecting anything. 

AnOldUR

@manyman297 The reasoning is probably that the controller will be in a standby mode and still draw a small amount of power. In my opinion, not enough to be concerned about unless you're storing for years, not just over the winter.

pthomas745

The thought of some owners with, lets say, very little skills at this sort of thing: taking out 4 lithium batteries and the complex heater wiring, solar controller issues, etc....is a nightmare for a simple 4 month over winter "storage".  And, then: having to put it all back. 

This is all seemingly overkill.

Sharon_is_SAM

Regarding requiring a disconnect of the panels from the controller:  If the “disable charging” function malfunctioned, charging and battery damage may occur.  So, physically disconnecting may also serve as a belt and suspenders approach.  

marleecamps

Timely discussion.  I replaced my stock AGM batteries with a single Lifetime 230 ah battery with built-in temp cutoff and will be taking my Tab 400 to storage next week.  I am in the metro area of Minnesota, with temps routinely below zero in January and February - and I will not have access to my camper while in storage.  

The product manual states that "a temperature between 50 and 95 degrees is ideal for long-term storage".  (And also that I should place it in a fireproof container.  ???)  So it seems that it's in my best interest to pull my battery and store it inside a heated structure like my basement  

Three questions for our experts here:

(1) Does anyone disagree with my assumption I need to pull the battery?

(2) How do I drain the battery down to 50% before doing so?

(3) Since the battery is required for the electric brakes to operate, do I need to wait until I reach my storage facility to pull it - and then reinstall it before the 30-mile drive home?  This will really be inconvenient but guessing it's necessary.

Thanks for any feedback and advice.

pthomas745

"Long term storage" for LiTime means...what?  1 year?  5 years?  The problems with some of the advice we get from the manufacturers is: they are white coat lab technicians and not RV owners.

What would their recommendations be for a 4 month storage period of an RV? 

Would you pull your battery in the summer because the temps were over 95 degrees?

marleecamps

@pthomas745 - The manual doesn't define "long term storage."  My rig will be at the storage facility for six months.

There certainly is conflicting information on line, but nearly all sources state that temps need to be above zero and battery discharged to 50%.

I'm still trying to figure out how I can discharge my battery before removing, as I will be towing my camper to the dealer for a glycol flush, and then towing it to the storage facility another 45 minutes away.  So even if I successfully discharge the battery at home before doing so, it will undoubtedly charge to full while towing - or simply sitting in the sun.  Is there a way to discharge it after removal?

Has anyone developed a good plan for handling lithium batteries during winter storage in a colder climate?

manyman297

@marleecamps You actually might end up charging your TV battery inadvertently as voltage will travel to the lower of the two and lithiums tend to have a higher resting voltage. I’ve even had this happen with my old AGMs…I realized the camper battery was providing a charge to my TV after hours of towing. 

Yes, discharging these batteries is going to be an issue. I may just run the fridge and fan all day and see where that gets me. 

manyman297

Here’s an article from LiTime…a little confusing and contradictory:

https://www.litime.com/blogs/blogs/how-do-you-store-lifepo4-batteries?srsltid=AfmBOorWs7MpIWu170mqHRIGqy2ZAyydXwZtdxwmWkccPTxvT932Mh7i

Long term is defined as 90 days or more. Storage temps for that length of time shouldn’t fall below 59 degrees. They also recommend discharging to 50% at the max…so you probably don’t need to discharge it that much. I’ve heard 80% is fine. They suggest it’s good practice to check the voltage every 3 months in storage. 

Looks like I’ll be disconnecting and storing these inside my house after all (ugh).

marleecamps

@manyman297 - After some more googling, I came across the recommendation to use a lithium charger to discharge the battery once removed from the camper.  Guess I didn't realize they can be used to both charge and discharge batteries.  This makes a whole lot of practical sense, and I will be ordering one. 

Given our climate, I believe removing the battery after towing it to the storage place seems to be the wise move, based on what I have read to date.  And at least it only weighs 45 pounds - pulling those two 70-pound AGM's would have been problematic.  In hindsight, it's possible I should have been removing those during winter as well.  

marleecamps

@manyman297 - good article.  Thanks!

On the positive side, I was very happy with the performance of my new lithium battery this summer while boondocking.  Filtered sunlight was enough to recharge them to full every day.  

manyman297

Ours were great but I did notice that it took a while to charge them back up. What solar panel are you using? We have the stock 160w panel on our 2021 400.

marleecamps

Factory delivered solar setup - no mods.