How to store power tool batteries: A comprehensive guide

As innocuous and mundane as it sounds, storing power tool batteries — and doing so properly — can have a tremendous impact on your device’s performance, lifespan, and even its safety. As with any electronic device, the changes that occur aren’t noticeable day-to-day, but rather stem from accumulating any infinitesimally small damage over time that slowly degrades your power tool and its battery. The most important aspects to consider pertain to storage temperature, humidity, and maintaining optimal charge levels when the power tool is not in use. To get the full picture, read the rest of our guide on how to store power tool batteries!

Storing power tool batteries: Why it matters

First off, let’s note that lithium-ion batteries (the kind you’ll find in most power tools these days) are not nearly as dangerous as many make them out to be. The technology has come a long way since its inception and modern tools have several failsafes in place, like comprehensive battery management systems, to prevent any sustained damage from harming you in the vast, vast majority of cases.

However, that doesn’t mean improperly storing power tool batteries won’t eventually increase the risk of something going wrong. Here are just a few of the most common consequences:

• Shorter Battery Lifespan: As we’ll explain in a moment, poor storage conditions (wrong ambient temperature) lead to cell degradation, which leads to the battery needing replacement sooner than later. 
• Reduced Power Tool Efficiency: Many things can contribute to this. Over time battery efficiency will decrease due to increased internal resistance. It means that more energy will be converted into heat instead of the power of your tool

If you already own a set of power tools and didn’t know how to store power tool batteries properly, chances are they’ve already degraded. To err on the side of caution, we recommend reading our guide about the Top Signs Your Power Tool Battery Needs Replacement.

How to store power tool batteries: Ideal conditions

Below, we outline some of the best practices to keep in mind for storing your power tool batteries. If you’ve read our guide on storing E-bike batteries, most of these points shouldn’t come as a surprise to you:

Store at an optimal temperature

Ideally, you should always store your power tool batteries between 10°C and 25°C (50°F to 77°F). Exposing them to extremes above and below this range can either increase the battery’s internal resistance or cause it to swell, leak, or even experience thermal runaway (which essentially means the battery can spontaneously combust).

Maintain moderate charge level

Try to keep the charge level between 40% and 60% when not in use. Avoid storing it with full charge or no charge at all, as a more balanced state prevents degradation of the battery’s internal components.

In practice, this means you can’t be completely hands-off when storing power tool batteries. At the very least, you’ll need to check their charge levels every couple of weeks. If they fall outside the 40-60% range, plug the device in for a while to bring it back up. 

Keep batteries in a dry environment

Humidity and moisture buildup are major enemies of lithium-ion batteries and can severely affect their lifespans. Excess moisture can cause corrosion on the battery terminals, which can lead to poor electrical connections and potential failure.

• Store batteries in a low-humidity environment.
• If you live in a humid climate, consider using a sealed plastic container with silica gel packs to absorb excess moisture.

Avoid sunlight exposure

Direct sunlight can cause the battery to heat up quickly, even if the surrounding air is otherwise cool. Because of this, power tool batteries should always be kept away from windows in a shaded or enclosed area. UV light also will age the plastic housing.

When in doubt, rely on the manufacturer

Lastly, one crucial power tool battery storage tip that shouldn’t be overlooked is to trust your manufacturers. Companies like EMBS are required to produce their batteries according to strict technical specifications. Therefore, the storage instructions are always formulated with your best interest and safety in mind.

The takeaway

How should power tool batteries be stored? The answer is simple: avoid moisture, direct sunlight, and exposure to exceedingly high and low temperatures. Keep the battery charge levels between 40% and 60%, and your power tool should serve you well for a very long time without detriment to its efficiency or safety.