How to Store LiFePO4 Batteries

People often store batteries without proper care, only to later find the battery short-circuited, fluid leaking, or not working for some reason.

While most of these problems aren’t an issue for Lithium batteries, especially lithium iron phosphate (LiFePO4 or LFP), they still require certain precautions. This is especially true when the battery is disconnected and in storage.

Many people think that disconnected batteries do not pose any risk since they are not using any power. There is also a common perception that batteries do not lose any charge when not used.

Unfortunately, these are misconceptions – completely wrong. Battery storage recommendations can vary from one manufacturer to another.

Below is the best advice on how to store LiFePO4 batteries.

Why is Proper Storage for Li-ion Batteries and LiFePO4 Batteries Essential?

When a battery is not connected, no external appliance draws power from it. However, this does not stop the battery’s internal chemical reactions from occurring.

LiFePO4 batteries do not require as many safety measures as Li-ion batteries. LFP batteries use stable compounds of iron that do not create any toxic gases or explosive reactions. Even so, LFP batteries are an expensive investment. Correctly storing a LiFePO4 battery can ensure that the money you invested does not go to waste.

Many batteries come with a battery protector. This can help to store LiFePO4 batteries safely. However, as a point of note, a battery protector should not be used to store a battery in a discharged state. Protectors work well for batteries with at least 40% to 50% charge, as discussed in the sections below.

How to Store Lithium Iron Phosphate Batteries?

The main factor influencing how to store lithium iron phosphate batteries is how long you plan to keep them in storage. Below are the main tips for storing LiFePO4 batteries and specific recommendations regarding storage time.

Main Tips for Storing Lithium Batteries

Disconnect Switch: Almost all manufacturers recommend storing lithium batteries after disconnecting them.

For motorhomes and caravans, simply using the disconnect switch on appliances will not disconnect the battery pack. Some components remain active, for example, sensors, even when there is no external load to draw power. The correct way to disconnect the battery pack is by disconnecting the [+] and[-] wires to the battery pack terminals.

Unlike other types of battery packs, a lithium battery does not require trickle charge voltage. Therefore, there is no need to provide a power source when the battery is stored. LiFePO4 batteries have a 2% monthly self-discharge rate, so they retain most of their charge capacity during storage.

It is crucial to store a lithium battery away from any fire, radiator, or heat source. Batteries have chemicals that can heat up and explode when exposed to high temperatures for extended periods.

When storing the battery, keep it away from conductive objects such as hairpins or other metals. These objects can cause a short circuit if they accidentally come into contact with both battery terminals.

The battery should not be used if it displays strange behaviour when taken out of storage. Strange behaviour includes any smells, fluid leaks, physical deformations, or other abnormalities.

Places with high magnetic fields should be avoided when storing a LiFePO4 battery because magnetic fields can disorient or damage the battery management system aboard a lithium-ion battery.

Short-Term Storage

Ensure you store the battery in a dry area. There should be no leaking fluids or corrosive gases that can enter it. The wet temperature range of LiFePO4 batteries can be between -20 degrees to 35 degrees C. Any changes in this range can make batteries rust or leak fluids, leading to a decrease in battery life or permanent failure.

When you disconnect and store LiFePO4 batteries, it is highly recommended that you use a lithium charger to charge them to at least 50% of the max charge capacity. This ensures an optimal charge when the battery is reconnected and helps preserve the battery’s overall condition.

Long-Term Storage

Self-discharge can increase when stored for long periods. Self-discharging can also increase when the battery warms and is stored outside the recommended storage temperature. To counter this, put LiFePO4 batteries in a warm place, and charge them sufficiently before you physically disconnect them. The ideal temperature range is 10℃ to 30 ℃.

When a battery is stored for longer than 3 months, it is best to run a charge and discharge cycle every three months. This will maintain the battery’s health and keep it in excellent working condition when it is taken out for use.

Cold temperatures stop the battery’s internal chemistries, increasing battery health. Therefore, keeping the battery in freezing temperatures is a good thing for preserving its health in long-term storage. However, the battery’s self-degradation rate should be taken into account. It is best to charge the battery to 40% to 50% of its capacity to keep it in optimal condition.

Ideal Storage Temperature for LiFePO4 Batteries

For LiFePO4 batteries, the temperature range depends on the storage time. Generally speaking, follow the guidelines below:

• Less than 30 days: -20℃ to 60℃
• Between 30 and 90 days: -10℃ to 35℃
• More than 90 days: 15℃ to 35 ℃

Storing LiFePO4 Batteries in Cold Weather (Winter)

Low temperature is not an issue for lithium batteries since it leads to slower chemical reactions inside the battery, increasing its life. However, while the battery chemistry enhances in cold weather, extremely cold temperatures may cause some battery components to crack (such as its plastic casing). Therefore, it is a good idea to store lithium batteries indoors and avoid extremely cold temperatures.

Storing LiFePO4 Batteries in Hot Weather (Summer)

Storing LiFePO4 batteries in high temperatures or out in the hot sun can pose serious threats to the battery. Extreme temperatures can cause internal heating of the battery resulting in unwanted chemical reactions. These can lead to uncontrolled battery voltage drops or even battery fires. Therefore, avoid storing batteries in high temperatures or outdoors in the sun for long periods.

Should LiFePO4 Batteries Be Disconnected From the System When Not In Use?

Yes, we recommend disconnecting LiFePO4 batteries from the system when not in use. Simply turning off the main switches isn’t enough.

Disconnect the battery terminal cables before storing the battery. If the battery is not uninstalled, there will always be a small current leak. This current can ruin the battery’s health or the appliance to which the battery is connected. This is because some components, such as sensors, are often designed to bypass the main disconnect switch.

How Do You Maintain a Lithium-Iron Phosphate Battery?

Lithium-ion batteries, including an LFP battery, are easier to maintain than lead-acid batteries. There are concerns, such as the possibility of fluid leaking in the case of a lead acid battery.

Besides the recommendations listed here, there are a few other maintenance tips that can ensure the performance of this type of rechargeable battery and an extended charging life. For convenience, we have listed these tips in our detailed guide to maintaining LiFePO4 batteries.

Conclusion

Due to its low self-discharge rate and several other benefits, a LiFePO4 battery is easier to store than any other lithium-ion battery or a sealed lead-acid battery.

However, learning how to store LiFePO4 batteries the correct way is essential to preserve battery health. Even though the battery chemistry is quite resilient, the physical components are still vulnerable to many environment-based factors.

Therefore, following the information above will be enough to store most lithium-ion batteries, especially liFePO4 batteries. Lastly, getting a good-quality battery can make the storage process much easier.

Check out the vast catalogue offered by Eco Tree Lithium for the best-in-class LFP batteries. These batteries come with a 6-year warranty, so you know they are made with quality in mind.

Frequently Asked Questions (FAQs)

What is the most important thing about storing lithium-ion batteries correctly?

Before putting lithium-ion batteries into storage, disconnect the lithium battery from the appliance. Remove the terminal wires, and keep the battery in the temperature range that the manufacturer recommends.