People often store batteries without proper care, only to later discover issues such as short-circuits, fluid leakage, or the battery failing to work altogether.
Although Lithium batteries, particularly lithium iron phosphate (LiFePO4 or LFP), are generally more resilient, they still require certain precautions—especially when disconnected and in storage.
A common misconception is that disconnected batteries pose no risk since they aren't actively drawing power. Many also believe that unused batteries maintain their charge indefinitely.
Unfortunately, these assumptions are incorrect. Battery storage guidelines can differ among manufacturers.
Here's some of the best advice on properly storing LiFePO4 batteries.
Even when a battery isn't connected to an external device, its internal chemical reactions continue to occur.
While LiFePO4 (LFP) Storage Batteries don't require as many safety precautions as Li-ion batteries due to the stability of their iron-based compounds—which don't produce toxic gases or explosive reactions—they are still a significant investment. Proper storage of an LFP battery helps protect that investment and ensures optimal performance.
Many batteries come equipped with a battery protector to assist in safe storage. However, it's important to note that a battery protector should not be used to store a battery that is fully discharged. These protectors work best with batteries that have at least a 40-50% charge, as outlined in the sections below.
1. Disconnect Completely: Most manufacturers recommend fully disconnecting lithium batteries for storage. In motorhomes and caravans, simply switching off appliances doesn't fully disconnect the battery pack—some components, like sensors, may still draw power. To completely disconnect, detach the positive (+) and negative (-) wires from the battery terminals.
2. No Trickle Charge Needed: Unlike other batteries, lithium batteries, including LiFePO4, don't require a trickle charge during storage. With only a 2% monthly self-discharge rate, they can retain most of their charge over time without needing a power source.
3. Avoid Heat Sources: Store lithium batteries away from heat sources, such as fire or radiators, as high temperatures can cause the battery's internal chemicals to overheat and potentially explode.
4. Keep Away from Conductive Objects: Ensure that metal objects like hairpins or wires don't come into contact with the battery terminals, as they could cause a short circuit.
5. Check for Abnormalities: After storage, inspect the battery for any signs of irregular behavior, such as strange smells, fluid leaks, or physical deformities. Avoid using the battery if any abnormalities are present.
6. Avoid High Magnetic Fields: Store LiFePO4 batteries away from sources of strong magnetic fields, which can interfere with or damage the battery management system.
Store the battery in a dry location free from leaking fluids or corrosive gases. LiFePO4 batteries can tolerate temperatures between -20°C and 35°C; variations outside this range may cause rust or fluid leakage, reducing storage battery lifespan or even causing permanent failure.
When preparing LiFePO4 batteries for short-term storage, it is recommended to charge them to at least 50% capacity using a lithium charger. This charge level helps preserve the battery's condition and ensures it is ready for use upon reconnection.
During long-term storage, self-discharge may increase, especially if the battery is stored outside the recommended temperature range or in warmer conditions. For optimal long-term storage, keep LiFePO4 batteries in a stable environment with a temperature range of 10°C to 30°C, and charge them adequately before disconnection.
If the battery will be stored for more than three months, perform a charge-discharge cycle every three months to maintain its health. Cold temperatures slow down the battery's internal chemistry, which helps preserve battery health. For extended storage in cooler environments, charge the battery to around 40% to 50% of its capacity to keep it in peak condition.
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 ℃
Cold temperatures are generally beneficial for lithium solar storage batteries as they slow down internal chemical reactions, which can prolong battery life. However, exposure to extremely cold conditions may cause certain components, like the plastic casing, to crack. To prevent this, it's best to store lithium batteries indoors, away from harsh winter temperatures.
High temperatures and direct sunlight can pose serious risks to LiFePO4 batteries. Excessive heat can lead to internal overheating, which may trigger unwanted chemical reactions inside the battery. 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.
Yes, it is recommended to disconnect LiFePO4 batteries from the system entirely when not in use. Simply switching off the main switches is insufficient.
Before storing, disconnect the battery terminal cables to prevent any small current leakage, which can otherwise damage the battery's health or the connected appliance. This leakage occurs because certain components, like sensors, are often wired to bypass the main disconnect switch.
With a low self-discharge rate and multiple advantages, LiFePO4 batteries are easier to store compared to other lithium-ion or sealed lead-acid batteries.
However, understanding proper storage practices is crucial to maintaining their longevity. While LiFePO4 chemistry is highly resilient, its physical components remain sensitive to environmental factors.
Following the guidelines outlined above will help ensure optimal storage for most lithium-ion batteries, especially LiFePO4. Additionally, investing in a high-quality battery can simplify the storage process and contribute to better overall battery health.
