How-To Extend Your Power Tool Battery's Lifespan

 Your cordless power tool batteries are a major financial investment. Getting the most from them saves you money, reduces work downtime, and ensures you stay productive whilst on the jobsite. The key to making them last is managing the three main factors that can destroy batteries: heat, vibration, and moisture.

Continue reading this guide to learn pro techniques that can maximize the performance and lifespan of your Milwaukee M18, DEWALT 20V MAX, Makita LXT, and other pro-grade battery platforms.

 Heat is the number one enemy of any lithium-ion power tool battery. Higher temperatures can permanently and irreversibly damage the battery’s internal chemistry, reducing its runtime and shortening its total lifespan.

1.  Storage: The ideal temperature for batteries is in a climate-controlled space, like a shop or basement, around 68°F (20°C).
2. Hot Vehicles: Never leave your batteries in a hot truck or van. Storing a fully charged battery in 100°F heat can reduce its total capacity by 30 percent or more in just one year.
3. Charging: Let a battery cool down for 15 to 30 minutes after heavy use before charging. Charging a hot battery will degrade it even faster.
4. Cold Weather: Cold temperatures will temporarily reduce a battery's runtime, but this does not cause permanent damage. Simply bring the battery inside to warm up, and its performance will return to normal. Never charge a frozen battery.

 Heavy vibration from tools like rotary hammers, grinders, and reciprocating saws can, over time, damage a battery's internal cell connections and circuit boards.

1. Transport: Store batteries in dedicated, foam-lined cases. Do not leave them loose in a toolbox where they can rattle against other tools.
2. Rotation: Get in the habit of rotating your batteries. Using 4 to 6 batteries in rotation instead of using the same two every day spreads the wear and tear evenly, which can extend the life of your entire collection.

 Moisture, humidity, and rain lead to corrosion on the battery terminals, which can block electrical contact and cause a short circuit.

1. Storage: Keep your batteries in dry, weatherproof toolboxes, especially on wet job sites or in damp basements.
2. Wet Batteries: Never charge a wet battery under any circumstances. Remove it from the tool and let it dry in a warm, low-humidity area for at least 24 hours before you even think about charging it.

 Modern smart chargers help, but your habits matter more.

1. The 20 to 80 Percent Rule: Lithium-ion batteries are happiest when kept between a 20 and 80 percent charge. Unlike older NiCd batteries, they have no memory effect, so you do not need to fully discharge them.
2. Charge After Cooling: As mentioned, always let a hot battery cool down before charging it.
3. Fast Chargers: Fast chargers are convenient, but they generate more heat. To maximize the long-term life of your batteries, use a standard-speed charger when you are not in a hurry.

 If you are storing batteries for an off-season (30 days or more), follow this simple protocol.

1. Charge to 50 Percent: Do not store them fully charged or entirely dead. A 50 percent charge, or about two lights on the fuel gauge, is ideal.
2. Remove from Tools: Store the battery separately from the tool.
3. Store Cool and Dry: Keep them in a climate-controlled, dry location.

 Check your batteries regularly. Wipe the terminals to keep them clean and inspect the housing for any cracks or swelling. It is time to replace a battery if you notice:

1. A significant drop in runtime.
2. The battery gets excessively hot during everyday use.
3. Any swelling, bulging, or cracking in the case.

Safety Warning: A swollen or damaged battery is a serious fire risk. Stop using it immediately and dispose of it in accordance with your local regulations for lithium-ion batteries.

 No. While modern chargers have shut-off features, it is best to remove the battery once it is charged. This prevents any potential heat buildup and is safer.

 You should avoid this at all costs. The extreme heat in a vehicle during the summer is the fastest way to destroy your batteries. The extreme winter cold will also sap their runtime.

 No. That was only necessary for old NiCd batteries. Modern lithium-ion batteries have no memory effect, and it is actually healthier for them to be partially charged and discharged.

 With daily professional use and proper care, you can expect 3 to 5 years of reliable service, or about 300 to 500 complete charge cycles.

 Charge them to about 50 percent (two bars on the gauge) and store them indoors in a cool, dry place, such as your shop or a basement, not in an unheated garage or shed.

Treating your batteries like the pro tools they are will save you thousands of dollars in replacement costs. By managing heat, protecting them from vibration, and keeping them dry, you will get years of reliable service. For over 75 years, Tool Crib of the North has supplied trade professionals with the best cordless tools and batteries from Milwaukee Tool, DEWALT, and Makita.

1. Shop All Power Tool Batteries
2. Shop Milwaukee M18 Batteries
3. Shop DEWALT 20V MAX Batteries
4. Shop Makita LXT Batteries