Winterizing your Lithium Batteries.
How cold weather affects Lithium batteries.
Cold weather is something that we have no control over, but something that we should consider when thinking about using lithium batteries in your camper’s electrical system. If you are in an area where temperatures will descend below freezing then we should to have an idea of how cold weather can effect your electrical system.
A battery’s job is to store energy, and it is a crucial part of the electrical system. We like to recommend lithium type batteries (lifepo4) because they are the lightest, most efficient, and longest lasting battery chemistry on the market. It’s lifespan is anywhere between 3,000-5,000 charge cycles, meaning its actually the best value when compared to the lifespans of other batteies. What can make lithium batteries unique is their sensitivity to temperature.
The BMS.
Every lithium battery is given a brain, and it’s called a BMS - this stands for Battery Managment System. Part of the design of the BMS is to protect the battery from adverse circumstances.
Low temperature is one of circumstances that can affect a lithium battery. For use in a campervan we recommend the BMS should have 2 scenarios related to low temperature where it will automatically disconnect the batteries internally to protect from damage.
Low temperature charging.
Every lithium battery has a low temperature limitation when you are charging the battery. To find out what this temperature is you will have to reference the specific battery’s data sheet. We find that the Battleborn 12v 100AH Lifepo4 battery is a very popular option, so lets use it as a reference.
BATTLE BORN 12V 100AH LITHIUM BATTERY
It has the ability to take a charge until the internal temperature reaches 32°F, once this temperature is reached the battery will disconnect itself from all charging sources. In other words they will not allow any power to enter the battery bank until they reach a tempature above 32°F.
Low temperature discharging.
Like the above limitation a lithium battery is going to internally disconnect when the temperature is too low while you are discharging the batteries. This means if you are not charging the batteries but are only using energy from them, the temperature limitation is going to be slightly different. The same Battleborn battery can be discharged until the internal temperature reaches -4°. Again, once this temperature is reached, the battery will automatically and completely disconnect itself. While the BMS is doing a good thing by not allowing the battery to be damaged, you can see how this could be a problem when you need your battery power and they are disconnected because they are too cold.
Using your lithium batteries in cold weather conditions.
Our first road trip to the Rocky Mountains.
The first and simplest way to use your lithium batteries in cold weather is to keep the interior of your camper warm enough so they do not disconnect themselves. This is the most common option because most campers also have a water system that must also be kept from freezing. We have had great success using a gasoline Webasto heater in our campervan and it keeps everything plenty warm while we are traveling.
If you are unable to consistently keep your camper warm in a cold environment there are other options.
Most lithium battery manufacturers offer a self heated battery. Instead of the BMS disconnecting your battery when it gets too cold, it will automatically turn on an internal heater to preserve an appropriate temperature. This is a great option if you plan on traveling in extreme cold weather conditions, or want to keep your system running during all seasons of the year.
Another option is a battery heat blanket. This is essentially the same concept as above, but will have to be plugged into a 120v outlet. This is a good option for a battery that does not offer an internally heated option.
Storing your lithium battery during winter.
If you are more of a seasonal traveler and plan on storing your camper over the winter months there are a few options we suggest.
Lithium batteries, if not being used, can be stored at lower temperatures than when you are charging or discharging them. Let’s take the same Battleborn battery we have been looking at for reference, it can be stored in climates down to -15°.
It is best to fully charged the battery before winter storage. You must be certain that it is totally disconnected from all charging and discharging sources.
Batteries self-discharge even when disconnected, it is a natural process that occurs in all batteries. On a full charge a single lithium battery can last in storage for more than a year, but if stored with an inadequate amount a charge the battery level can go below the level that the BMS can not protect and your batteries can become damaged.
The proper way to turn off your electrical system.
The process is easy to turn off your electrical system. It is a systematic way of turning off all the things connected to the batteries.
Take our Drop-in electrical system for example, we make all the breakers and switches accessible so you can easily turn off your system if you need to place it in storage.
Here are the steps we recommend:
1.Turn off your DC loads such as the refrigerator, heaters, or fans.
2. Turn off any AC appliances, like an air conditioner, then turn the inverter off.
3. Turn off your DC breakers, this should include the DC panel, and all charging sources.
4. Turn off your main power switch.
That’s it!
Now your batteries are good to store per the specifications of the manufacturer. To turn your system back on you simply need to turn everything back on in reverse order. If you will be storing the batteries in colder conditions than what it can handle then you will need to remove the batteries from the camper and store them indoors where the temperature suffices.
We hope this guide has been helpful in understanding how to care for your lithium batteries in cold weather conditions. Should you have any further question you can leave a comment below.
