Lithium and winter storage

[avanti]

In the last year or so, the tone of discussion concerning lithium battery systems has noticeably shifted from treating them as exotic to thinking of them as routine. I fully understand why one would covet such a system, and they certainly have come a long way. However, I keep tripping over the "winter storage" issue. We store our rig outdoors without access to shore power, which seems to make Li almost a non-starter for us. This applies even to warm climates, since there are few places in CONUS that don't see frigid temperatures at least occasionally. I am not talking about cold-weather charging--that is manageable. I am concerned about storage in very cold conditions.

I am curious what all you folks who are forging ahead with lithium batteries are doing (or planning on doing) about cold weather storage. The alternatives I can think of are:

1) Follow DavyDD's lead and get your rig a cozy indoor home.
2) Limit your storage options to places with power and keep the van heated all winter.
3) Remove your batteries as part of winterization and store them indoors.
4) Get one of the few battery chemistries that don't have freeze-damage issues.
5) Ignore the issue and hope for the best.

So, what are folks doing?

[mkguitar]

6.) electric blanket?


I'm staying away from lithium for a few more years


I did my battery 'sperimentin' and when an odyssey brand ( not lithium) battery shorted internally and started smoking I was lucky to be in the garage and used bolt cutter to cut the cables and threw battery on to driveway where it burned down.


I have a fear of dendrites


Mike

[rowiebowie]

All good points Avanti. I've seen some recent (as yet, unsubstantiated) claims of lithium iron phosphate's that can tolerate sub zero temps. I assume they mean disconnected with no chance of damage from charging or use.

My case is much simpler. I moved the lithiums inside and always plan to keep the inside heated above freezing. Automatic if we are camping, and not necessary (for all practical purposes) where I live in deep S. Texas.

I'd like to say that it never freezes here, except I remember a 3-day period in 1983 where temps got down in the teens and and never got out of the 20's during the period. My home water pipes froze and so did the top crust of the bay (we're on the Gulf of Mexico). So you can never say never.

[@Michael]

Originally Posted by avanti

2) Limit your storage options to places with power and keep the van heated all winter.
3) Remove your batteries as part of winterization and store them indoors.

My campervan is stored alongside my garage, so power is available.

Either 2 or 3. Low temps here often approach -20f, and -30f is possible. I have a battery warmer, but am uncertain if it can keep up in extreme temps. Last winter on nights that went below -0F I left the battery in, ran the furnace to keep a bit of heat in the van, and had the battery warmer on just in case.

This winter I should have better data - I have a couple of sensorpush sensors and will track battery vs. camper temps during extreme cold. If the battery warmer can keep up, I'll leave the battery in.

If it looks like the warmer cannot keep up, or if I'll be out of town for an extended period, I'll remove the battery.

Originally Posted by avanti

1) Follow DavyDD's lead and get your rig a cozy indoor home.

I bought lottery tickets. Should be good to go with plan A.

[rickst29]

My first option (and the one I use) is to take the batteries out and bring them into the house. They are extremely light.

My second option (and I've used that too, over one mild Winter (with lowest temps just a couple of degrees below zero) Is to leave the in the RV. I have 'battery disconnect' circuit breaker, replacing the fuse on the +12v "hot" wire which gopes back the the DC fuseboard panel.

In Spring when it was time to start things up, I flipped the breaker back on and charged it using the 30A shorepower connector and power converter. It didn't take a lot, self-discharge in disconnected batteries is VERY slow, and it's barely noticeable over a 4 month period.

Where you used to have concerns with keeping the lead acid batteries unattended and unused for several months WITHOUT plugins, LFP batteries will give you no problem. They can't be charged below freezing - but they will last for several months and still be more than 85% full, and they can down to 12-15% before you begin to hurt them. They have much lower and slower self-discharge thabn lead-acid batteries.

[rickst29]

In cold weather, they heat themselves from power inside the battery to warm up the cells, before starting to accept charge current from the Charger. They're smarter, but cost a lot more than traditional LFP batteries with dumber BMS boards.

[Boxster1971]

I plan to have lithium batteries in my next B-van. The batteries will have some form of heating them when cold. I use my B-van as a second vehicle and park it in my driveway off an alley behind my townhouse. I have electrical power available so when it gets too cold I can always plug into the 30A outlet near the van parking spot. I also plan to have significant solar (400W+), as I have now, to keep the batteries charged when I’m not using the van.

[Arlo]

Cozy home in heated garage and Valence battery pack storable to -40 if there’s a prolonged power outage. Putting a wood stove in the garage seemed a bit much.

[Davydd]

It is rare for a home without a 15a household Duplex plug on the exterior. Heck you could go through a window if you had to. That’s all you need. It is mandated by code as long as I have practiced architecture. If you can’t find that and an extension cord then you are out of luck on lithium unless you live in a climate that does not get below -4F. You can store lithium at below -32F down to -4F you just cannot charge it until temperature rise above freezing. If you have electricity you can put a heating pad under them. A 10 amp elecrric heating pad heated my 800ah battery bank and maintained it above 42 degrees F. at -20F. Ambient temperature in Minnesota. I stored my van outside in my first two years. Lithium batteries can last longer than lead-acid over a winter storage as they don’t naturally discharge as fast as lead-acid. If your batteries are under charge the temperature of the battery probably will be above 32F even it ambient temperatures go into the mid-twenties. It is the battery temperature, not ambient you need to be concerned with for charging though it is best to keep them above 42F. I have belts and suspenders control of all this that I can monitor down to the cel. Maybe more information than needed but I observed what happens.

I’m going on 5 years with my lithium batteries. I’d never consider lead acid again especially if you want over 400ah’s of battery or more. They are 40% of the weight of lead-acid. They last infinitely longer In cycles than lead-acid. They charge faster. They take up less room in an amp hour to amp hour comparison. You can discharge them far greater. Lead-acid has a 50% discharge Recommended rate because lead-acid in general doesn’t have BMS’s worth diddly from the RV manufacturers and usually are fewer amp hour battery banks subject to accidental complete discharge which affects battery life. You can say you can discharge greater than 50% but they still don’t come close to lithium longevity.

[Davydd]

Originally Posted by Arlo

Cozy home in heated garage and Valence battery pack storable to -40 if there’s a prolonged power outage. Putting a wood stove in the garage seemed a bit much.

The Valence battery chemistry was changed to LiFePo4 from LifeMgPo4 and no longer go down to -40F (same as AGM) but now down to -4F same as just about every other lithium battery system available for RV coach batteries. There is a positive trade off. The Group 27 battery profile size is rated at 144ah vs. 138ah.

[rickst29]

Originally Posted by Boxster1971

I plan to have lithium batteries in my next B-van. The batteries will have some form of heating them when cold. I use my B-van as a second vehicle and park it in my driveway off an alley behind my townhouse. I have electrical power available so when it gets too cold I can always plug into the 30A outlet near the van parking spot. I also plan to have significant solar (400W+), as I have now, to keep the batteries charged when I’m not using the van.

You won't want to do either plug-in charging OR solar charging, if the BMS isn't smart enough to reject all that charge current in cold weather. In the "cold weather" batteries, incoming power is first sent to the internal heater coils, and only later used for charging.

But very few batteries have that. You will need to buy batteries WITH that feature.

[rowiebowie]

Originally Posted by rickst29

You won't want to do either plug-in charging OR solar charging, if the BMS isn't smart enough to reject all that charge current in cold weather. In the "cold weather" batteries, incoming power is first sent to the internal heater coils, and only later used for charging.

But very few batteries have that. You will need to buy batteries WITH that feature.

You make a good point to turn off solar during cold winter periods. I'll bet not many have thought of that.

[Davydd]

Originally Posted by rickst29

You won't want to do either plug-in charging OR solar charging, if the BMS isn't smart enough to reject all that charge current in cold weather. In the "cold weather" batteries, incoming power is first sent to the internal heater coils, and only later used for charging.

But very few batteries have that. You will need to buy batteries WITH that feature.

Advanced RV has always had that feature in their battery management system. The heating comes off the battery itself and the battery under charge can accept solar, second alternator idling and shore power simultaneously up to what a 4.0 wire will accept and then shut down when 100% charged until the battery drops to 90% charged. It then will accept solar or shore power again while in storage. While in storage the coach battery will in turn Trik-L-Start charge the chassis battery if you have that set up. Like I said previously you only need a 15a outlet not a 30a as you will not need anymore power.

[markopolo]

Avanti is looking for storage recommendations at cold temperatures but I think the following adds to the discussion.

If optimal operation temperature requirements are to be met by the system design then it's easier to see the need for heat for any permanent lithium installation.

My understanding is that Advanced RV keeps the battery temperature above 41F.

41F is the point where Trojan recommends halving the charging current.



Cold, Cool, Normal, Warm, Hot .........








Edit: added better image below



It could be said that the cells need to be Warm to Perform.

[Davydd]

41-42 deg. is the optimum temperature cited for maximum optimization of lithium batteries. I think ARV BMS shuts down charging at about 36 deg. a bit above freezing for safety. When that happens the ambient temperature will be well below freezing as lithium batteries themselves have a built in heat sink when under charge or in use. So a dip below freezing at sun up usually will not be much of a factor while on the road.

Now that I store inside a heated garage maintained at 45 deg. I haven't had a chance to test my system again for the past two winters except on the road. I learned and tested my battery system accidentally and deliberately my first two winters storing outside. I have endured temperatures down to -15F while traveling with success and, yes, the diesel started. ARV's battery systems and BMS's have improved since my installation but I don't know how much or any details other than that their Elite batteries that I have, have improved but are now the lowest offering below Valence and Volta in their lineup.

I know little about other lithium systems or their BMS from other manufacturers as how they manage and perform in safeguards. I am just saying it is possible and could be implemented. ARV's system, BTW, does not need an AGM battery in the system to restart a lithium battery bank like that Roadtrek Etrek system.

[DUTCH in Atlanta]

#2. Stored under an open carport in my driveway, connected to 15 amp service at the house. Set the Truma thermostat at 45°F, since the Li3 battery is inside the coach. Bigger concern is freezing the fresh and/or grey water tanks and lines. This for a Coachmen Galleria Li3 in a NE Atlanta suburb, where we do get down into the teens.

[black88mx6]

#2 limit to storage with plug

2021 Coachman Galleria LI3 - Northeast Ohio Winter
Batteries are inside coach

10 or so nights in average below -4
Coach will be stored outside next to garage with 30a service.
Coach will have LI3 system with Xantrex battery blanket/heaters. (Coachman’s first)
Will use battery heaters to stay as above -4 monitored by onboard and SensorPush vi wifi.
Will add aux electric heater to battery area with built in thermostat if necessary.

[Davydd]

As mentioned you don't have to heat the whole coach or even the space where the batteries reside. I have 10 amps of electric resistant pads to heat an 800ah battery bank with direct conduction heat. If batteries are in use or being charged they have their own internal heat and the heating pad may not come on until the ambient temperature drops into the mid 20s. Thermostatically controlled they are not on all the time. I can observe all that on my Silverleaf screen down to the individual cell temperatures to give me a good grasp of what really goes on.

Of course, the Winnebago Revel literature says when you get up and go your batteries, having been heated with a whole cabin heater are good to be charged after a few hours of driving to you destination. I don't know if they have direct heat. I guess that is a simple way to go as long as storage temperatures don't go below -4F. I don't know what others say or do. Most lithium installations are now inside the cabin. Mine now are in an insulated box below the floor. ARV still installs their Elite system in a box below the floor, but installs the Valence and Volta systems inside the van.

[Boxster1971]

Originally Posted by rickst29

You won't want to do either plug-in charging OR solar charging, if the BMS isn't smart enough to reject all that charge current in cold weather. In the "cold weather" batteries, incoming power is first sent to the internal heater coils, and only later used for charging.

But very few batteries have that. You will need to buy batteries WITH that feature.

I'm planning to have a Lithionics Battery with built-in heater and a Smart BMS that controls charging and heating via a temperature sensor. It would work much like the Advanced RV system that Davydd described.

I understand that a 15A outlet is adequate to provide battery heating and charging functions in cold weather. But I have a 30A outlet available that I installed in my driveway some years ago to be able to run A/C and use van in driveways as a quest house.

[Buford Wilson]

Originally Posted by avanti

I am curious what all you folks who are forging ahead with lithium batteries are doing (or planning on doing) about cold weather storage.

So, what are folks doing?

Avanti, I had the same question. Thanks for raising the issue.

I store my Roadtrek Zion SRT with AGM outside during the winter, no access to 110 power. Temperatures down to -35F. Batteries kept charged through solar (and Drone Mobile remote start when panel covered with snow).

From the replies, it looks like lithium batteries won't work for me. Thanks.