Winter - Lithium battery charging

[kavm]

We have a winter camping trip planned in December and early January - starting from SLC, visiting Picacho Peak, Tucson, Chiricahua National Monument, Big Bend and so on. In prep for that - I need advice from the knowledgeable folks on the forum:

• We have 2 lithium batteries in the camper.
• The camper is parked in a covered commercial warehouse facility that is not heated. So, the temperatures there can drop below freezing during a cold spell.
• Last camping trip was around Labor Day weekend. So, it is likely that when we take the camper out, the batteries might not have much charge left.
• We can ask the storage facility to plug it into power. That's what we normally do. The catch this time, however, is that the temperature around the time we are starting the trip could be low (below freezing), if there is a cold spell.

So, I am not entirely sure if I should ask them to plug it in? The alternative is that we start out with discharged batteries, which is not good (even though our first campground will be a commercial one).

One other thought is that we can ask them to plug it no for a day or two earlier when we know that the temperatures are higher, but it is hard to time such things.

Any advice?

[alanmalk]

Originally Posted by kavm

...
One other thought is that we can ask them to plug it no for a day or two earlier when we know that the temperatures are higher, but it is hard to time such things.

Any advice?

I'm sure you are aware that if your batteries are not internally heated then charging a (lithium) battery when it's internal temperature is below freezing is never recommended.

But since you have flexibility between now and your trip start, just pick a day in the middle of a warm spell and ask them to plug in to AC and turn on the charger. Be sure to turn it off after a couple of days or earlier, should the temperature drop.

Once you occupy the trailer your heater will keep everything above freezing and you can charge any time. But keep in mind, while driving your tow vehicle will also act as a charger, so pay attention to the battery temperature.

[kavm]

Thank you! Yes, that's why I was asking the question.

I believe batteries do have a battery management system that prevents them from charging below 32F but I am not 100% certain. I have forgotten the brand but they were OEM from Escape in 2021.

[JohnK]

Originally Posted by kavm

Thank you! Yes, that's why I was asking the question.

I believe batteries do have a battery management system that prevents them from charging below 32F but I am not 100% certain. I have forgotten the brand but they were OEM from Escape in 2021.

kavm, you say you're not 100% sure if your batteries have BMS. If they don't, you are your batteries' BMS. The stakes are potentially very high here with your trailer being stored in a publicly used facility and lithium batteries having the potential to catch fire during charging if they are not managed. My humble suggestion would be for you to lay your own eyes and hands on your trailer in storage and not trust that to storage personnel. Lithium batteries characteristically do not lose power in storage IF they are disconnected from everything including including your solar controller whether or not your trailer is in sunlight. I hope you go to your trailer and that you find the batteries in the same state of charge in which you left them and that they have a BMS.

All the best.

John

[kavm]

Originally Posted by JohnK

kavm, you say you're not 100% sure if your batteries have BMS. If they don't, you are your batteries' BMS. The stakes are potentially very high here with your trailer being stored in a publicly used facility and lithium batteries having the potential to catch fire during charging if they are not managed. My humble suggestion would be for you to lay your own eyes and hands on your trailer in storage and not trust that to storage personnel. Lithium batteries characteristically do not lose power in storage IF they are disconnected from everything including including your solar controller whether or not your trailer is in sunlight. I hope you go to your trailer and that you find the batteries in the same state of charge in which you left them and that they have a BMS.

All the best.

John

I am sorry but this is a commercial facility and it is not possible for customers to enter it. I am also not sure what my looking at them is going to accomplish. I am hardly a human-fire extinguisher. The storage personnel manage a RV repair and rental facility, so they have more training. The camper has been stored in the facility for 2.5 years and it has been charged in this manner in the same facility many times.

I will try to get the brand of the battery. I believe I researched them when we got the camper from Escape and they had a BMS. I don’t remember the brand, and am, therefore, not able to (re-)confirm it.

I am not sure what this advice really accomplishes.

[Perry Butler]

All lithium batteries have a BMS. The question is, does your BMS have a low temperature shutoff?

You should have had your batteries charged to 60-80% SOC, and then disconnected your battery ground before you stored your camper. Had you done that you could have just reconnected the battery cables and you would have had 50-70% charge when you decided to go camping next year.

According to my talk with Battleborn in 2020, their batteries can freeze and break at temps below -17° F. Some can go below -20, but you're in a danger zone if you leave them outside at those cold temps. Since it can get below -20° in Minnesota I'll be removing our SOK batteries till we leave in the middle of January.

So the question you need to ask is, how often does it get to -20° in Salt Lake City?

Food for thought,

Perry

[kavm]

Originally Posted by Perry Butler

All lithium batteries have a BMS. The question is, does your BMS have a low temperature shutoff?

You should have had your batteries charged to 60-80% SOC, and then disconnected your battery ground before you stored your camper. Had you done that you could have just reconnected the battery cables and you would have had 50-70% charge when you decided to go camping next year.

According to my talk with Battleborn in 2020, their batteries can freeze and break at temps below -17° F. Some can go below -20, but you're in a danger zone if you leave them outside at those cold temps. Since it can get below -20° in Minnesota I'll be removing our SOK batteries till we leave in the middle of January.

So the question you need to ask is, how often does it get to -20° in Salt Lake City?

Food for thought,

Perry

Thank you! We do not have temperatures in that range. Lowest we get to is single (positive) digits. I do not think I have seen negative in Fahrenheit scale.

And, although our storage facility is not regularly heated, there are people there (as it is a working warehouse). They do heat it some. So, I don’t think it goes too far below 32F there for long periods of time.

[JohnK]

Lithium battery temperature limitations vary across brands. Our Li Time battery storage temp limits are +14F - +122 with recommended storage state of charge at 50%.

John

[kavm]

The batteries on our camper are - https://gopowersolar.com/products/10...solar-battery/
--------------------
Here is the info from the product sheet:

• Compatible with all Go Power! solar, inverters and charge controllers
• Max Power Capacity; carries almost double the power of regular batteries
• Lightweight
• Quick charging
• Built-in Battery Management System (BMS)
  • Over and under voltage protection
  • Over and under temperature protection
  • Charge and discharge over current protection
  • Short circuit protection

Safety Features
Go Power! Lithium batteries feature a built-in Battery Management System (or, BMS) which ensures safety and long battery life by constantly monitoring battery performance, internal temperature, and other critical elements required in safely functioning battery.

Go Power! LiFePO4 Lithium batteries feature several safety components in the BMS, which Include:

• Over and under voltage protection, which disconnects the battery from the load or charger, to prevent damage if it occurs
• Over and under temperature protection, which also disconnects from the load if the temperature limits are exceeded
• Charge and discharge over current protection, which automatically balances the voltages during recharge cycles to bring all the battery cells to full charge at the same time, ensuring longer battery life.
• Short circuit protection, which open circuits the battery terminals if a short is detected

[Perry Butler]

Originally Posted by kavm

The batteries on our camper are - https://gopowersolar.com/products/10...solar-battery/
--------------------
Here is the info from the product sheet:

• Over and under temperature protection

Since you have "Over and under temperature protection" you are golden as long as you completely disconnect your batteries. There can be parasitic loads on your battery that can still exist if you just hit the battery disconnect switch. It depends on the employee who wired your camper. I would disconnect the ground post on your battery.

Food for thought,

Perry

[emers382]

It's unfortunate that the chance of fire whilst charging was brought up in this thread. I follow pretty closely the cases of lithium battery fires and it appears most are in ebikes or scooters that are not being charged with the originally supplied charger, which is recommended.

The more I read though I'm perfectly happy to top up my lead acid batteries with distilled water from time to time, and have them stay charged in my trailer shelter (open at rear) by the solar all winter (at -40 at times) without worrying about freezing. The only time I ever plug in the trailer at home is to precool the fridge before a trip.

We plan to have another winter without traveling south since Beth just had a heart attack on Sunday, she is fine after a couple of stents put in Monday, but no travel into the US until ?

[JohnK]

Good news. Your batteries are well equipped. Good and important stuff to know. I did not mean to offend you in my original reply. Having been cockpit crew in passenger carrying airplanes in my work life I was trained to take lithium batteries much more seriously than we do lead acid batteries, and that included being specifically trained in lithium battery fire handling. For safety reasons it’s my opinion that RV trailer owners should be more knowledgeable and less casual about our lithium batteries than we had to be about our lead acid batteries.

John

[kavm]

No worries! No offense taken. Unfortunately, we simply are not technically proficient in this matter, but not for the lack of effort. And, some of the strategies brought up here are harder to implement in our specific scenario. If we completely disconnect the battery, the storage facility will not be able to raise and lower the landing gear when they take it inside their protected storage space. So, we need to leave them on as that's the only option, even though we had a battery disconnect switch installed by a RV mobile tech.

[alanmalk]

Originally Posted by Perry Butler

Since you have "Over and under temperature protection" you are golden as long as you completely disconnect your batteries. There can be parasitic loads on your battery that can still exist if you just hit the battery disconnect switch. It depends on the employee who wired your camper. I would disconnect the ground post on your battery.

Food for thought,

Perry

Just repeating what many of us already know. Not all BMS brands will have "under temperature protection". As a matter of fact, none of the 5 lithium batteries that I own have this, so I have to pay close attention to the temperature before I hook up my charger(s). (3 of these batteries are in use for fishing applications, 2 in the trailer). I did take the easy route with my trailer and installed disconnects on the + and - sides of my trailer batteries - to save the 90 seconds of effort of unhooking wires. But now it becomes essential that I remember to reconnect the power to ensure the emergency brakes work when towing.

If there is a bottom line here, it is that lithium batteries are not as "install and forget" as AGM batteries.

[John in Santa Cruz]

Originally Posted by emers382

It's unfortunate that the chance of fire whilst charging was brought up in this thread. I follow pretty closely the cases of lithium battery fires and it appears most are in ebikes or scooters that are not being charged with the originally supplied charger, which is recommended.
...

Lithium battery fires are almost entirely the domain of Lithium Ion batteries, and not the Lithium Iron Phosphate (LFP, LiFePO4) batteries we're using in our trailers.

[emers382]

Originally Posted by John in Santa Cruz

Lithium battery fires are almost entirely the domain of Lithium Ion batteries, and not the Lithium Iron Phosphate (LFP, LiFePO4) batteries we're using in our trailers.

Thanks John for clarifying that. I didn't know which type of lithium was being put into Escapes as I usually don't follow those threads.

Hopefully all batteries in the future will be designed so that fire is a non-concern.

[John in Santa Cruz]

the problem is, Lithium Ion chemistry has a higher energy density, LFP batteries are both larger and heavier for the same amount of power as Li-Ion.

Also, Li-Ion aren't used for 12V batteries because they are 3.6V per cell, and charge at 4.2V, so a 4 series cell battery has 14.4V nominal, and 16.8V charging, thats just too high. a 3 series battery would only be 10.8V nominal, too low.

LFP batteries are 3.2V per cell, and 3.6V charging, so a 4 cell batt is 12.8V nominal, and 14.4V max charging, which is nicely within the expected range of a 12V battery.

[oldwave]

Its been said to not store them below -15 f to be safe. Its safe to discharge them sub 32 degrees just not to charge. Since they are inside the camper you can heat up the camper cabin to raise the temp to allow charging (he bms will stop charging until the temp of the battery is above freezing.) A infrared thermometer is your friend, cheap and you can measure the temp of the batteries (as well as the temp of your wheels if need be.

I monitor my trailer remotely with a cerbo gx and temp measuring in the bay where my batteries are located. I have seen the charging stop below 32 and resume when the temp rises (solar charging)

[kavm]

Originally Posted by oldwave

Its been said to not store them below -15 f to be safe. Its safe to discharge them sub 32 degrees just not to charge. Since they are inside the camper you can heat up the camper cabin to raise the temp to allow charging (he bms will stop charging until the temp of the battery is above freezing.) A infrared thermometer is your friend, cheap and you can measure the temp of the batteries (as well as the temp of your wheels if need be.

I monitor my trailer remotely with a cerbo gx and temp measuring in the bay where my batteries are located. I have seen the charging stop below 32 and resume when the temp rises (solar charging)

Thank you! That's a good idea. We can heat the camper a bit during the day to allow solar charging while we drive...