How Do You Store Lithium Batteries for Seasonal Equipment?

Storing seasonal equipment batteries feels risky. Improper storage can degrade them or even cause a fire. Following a few simple steps will keep your batteries safe and ready for next season.

To store lithium batteries for seasonal equipment, charge them to 30-50% capacity. Store them in a cool, dry place, ideally between 40°F and 80°F (5°C to 27°C). Avoid extreme temperatures and direct sunlight. It's a good practice to check the charge every few months.

Proper storage seems simple, but many of my clients, like Michael from the US, often ask about the specifics. They worry about ruining expensive batteries over the winter. The details matter, especially with new regulations and best practices. Let's break down exactly what you need to do to protect your investment and ensure your equipment is ready to go when you need it.

How to store a lithium battery for winter?

Winter is approaching, and your equipment batteries are at risk. The cold can kill them, forcing you to buy new ones. Here’s how to properly prepare them for winter storage.

For winter storage, charge the battery to about 40-50% State of Charge (SoC)¹. Disconnect and remove it from the device. Store it indoors in a cool, dry place, away from freezing temperatures. A basement or a climate-controlled closet is an ideal location.

Storing lithium batteries for winter isn't just about avoiding the cold; it's about preserving their longevity. I often tell my clients that a battery is like a living thing; it doesn't like extremes. When a lithium-ion battery gets too cold, especially below freezing (0°C or 32°F), its internal resistance increases. If you try to charge it in this state, you can cause lithium plating on the anode, which is irreversible damage. This permanently reduces capacity and can even lead to internal short circuits. That's why we at Litop always advise bringing batteries indoors for the winter.

This is becoming more than just a best practice. In Europe and the US, warehouse storage regulations for lithium batteries are getting much stricter. They're cracking down on fire safety standards. If a fire happens and your storage wasn't up to code, insurance might not cover the damage. For our B2B clients, this is critical. A shipment could be refused, or you could face fines. It's a serious business risk. Here’s a simple checklist to get your batteries ready for their winter hibernation.

Winter Storage Checklist

Can lithium batteries be stored in an unheated garage?

Your garage is convenient for storage, right? But for lithium batteries, an unheated garage in winter can cause permanent damage, forcing you to buy a costly replacement next season.

It is not recommended. Unheated garages can experience freezing temperatures and wide temperature swings. This can irreversibly damage the battery's internal components, reduce its capacity, and shorten its lifespan. A climate-controlled indoor space is always the safest option for long-term storage.

I get this question a lot, especially from customers like Michael who deal with high-value medical equipment². The garage feels logical, but it's a trap for lithium batteries. The main enemy is temperature fluctuation. An unheated garage can drop below freezing in winter and get incredibly hot in summer. Both extremes are bad for battery health.

Freezing temperatures, as I mentioned, can cause permanent damage, but even just storing them in the cold slowly degrades them. On the other hand, high heat (above 45°C or 113°F) accelerates the chemical reactions inside the battery. This leads to faster capacity loss and can even cause thermal runaway in extreme cases, which is a serious fire risk. For our clients in the medical device field, battery reliability is non-negotiable. A failed battery isn't just an inconvenience; it could be a critical failure. That's why we stress the importance of stable, moderate storage environments. An unheated garage is simply too unpredictable and risky for your valuable batteries.

Lithium Battery Storage Temperature Guide

How to store lithium batteries when not in use?

You have spare batteries or batteries from unused gadgets. Just leaving them in a drawer can ruin them or create a safety risk. You need to follow a simple storage routine.

For any long-term storage, charge the lithium battery to a partial state, around 30-50%. Store it in a cool, dry place, away from direct sunlight, heat sources, and metal objects. Keep it in a protective case if possible to prevent short circuits.

This is the single most important rule for long-term battery health, and it's based on the battery's chemistry. Storing a lithium-ion battery at 100% charge is like holding a rubber band stretched out. The high voltage puts stress on the internal components, accelerating capacity loss. Over a year, a fully charged battery can lose up to 20% of its capacity, even if it's not used.

Conversely, storing a battery at 0% is also dangerous. It can slip into a deep discharge state. When this happens, the battery's protection circuit might shut down permanently, making it impossible to recharge. This is a common reason for "dead" batteries after long storage. That's why we at Litop, especially for our custom-shaped batteries for wearables and medical devices, always recommend a storage charge of 30-50%. This "resting state" minimizes stress and degradation. It reduces after-sales headaches for our clients and ensures their products work perfectly when the end-user finally opens them. It's a small step that has a huge impact on product quality and customer satisfaction.

Impact of Storage State of Charge (SoC) on Capacity Loss (1 Year at 25°C/77°F)

What is the 80 20 rule for lithium batteries?

You hear tips like the "80/20 rule" for batteries. Ignoring this advice could be drastically shortening the lifespan of your devices without you even realizing it. This is a simple habit for longevity.

The 80/20 rule is a guideline for daily use to maximize battery lifespan. It suggests keeping the battery charge between 20% and 80%. Avoid fully charging to 100% or letting it drain to 0% regularly, as these extremes stress the battery.

The 80/20 rule is different from the long-term storage advice, but it's based on the same principle: avoiding stress. This rule is for daily use. A "charge cycle" is one full discharge and recharge, from 100% to 0% and back. Lithium-ion batteries have a limited number of these cycles, typically 300-500. However, you can significantly increase the number of effective cycles by using partial charges.

Keeping the battery between 20% and 80% means a smaller Depth of Discharge (DoD). Instead of one full 100% cycle, you might do several 60% cycles (from 80% down to 20%). This is much gentler on the battery chemistry and can extend its total lifespan by three or four times. At Litop, we design our Battery Management Systems (BMS) with this in mind. For our B2B clients, we can even customize the BMS to set charging limits, automatically stopping the charge at 80% or 90% to enforce this longevity strategy. This is especially valuable for industrial or medical equipment where battery replacement is costly and disruptive. It’s about building a smarter, more durable product from the inside out.

Depth of Discharge (DoD) vs. Cycle Life

Conclusion

Proper storage and use are simple. Store batteries at a 30-50% charge in a cool, dry place. For daily use, try to keep them between 20% and 80%. These small habits protect your investment and ensure your equipment is always ready when you need it.