How to Make Your Power Tool’s Rechargeable Battery Last Longer

May 21, 2022

large dewalt drill

Keeping your cordless power tools in good condition requires regular use, care, and maintenance. If you want to preserve the high performance and capacity of your power tool’s rechargeable batteries for years to come, consider these charging and storage tips.

How to Preserve Battery Life

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Getting a longer battery life from your cordless power tools requires understanding the different rechargeable battery types, battery capacity, and other common terms used concerning rechargeable batteries.

Keep these common terms in mind to extend your device’s battery life:

  • Ampere Hour (Ah) – How much charge the battery can store
  • Voltage (v) – How much power the battery can provide
  • Battery Type (Li-ion, Ni-Mh, NiCd) – The type of materials used to make the battery
    • Li-ion (Lithium Ion)
    • NiMh (Nickel Metal Hydride)
    • NiCd (Nickel Cadmium)
  • Memory Effect – A reduction in capacity due to improper charging
  • Cycle Life – How many times a battery can be recharged before noticeable performance issues
  • Self-Discharge – The amount of charge lost when a battery is not in use

Regardless of the battery type, do not completely drain the battery. In fact, partial discharges are better for lithium-ion batteries and NiCd and NiMh batteries may only need to be fully discharged every 20 to 30 days to offset the memory effect.

A major aspect of preserving your battery lifespan is regularly using it. When your power tools are idle for extended periods of time, they lose charge and can experience a reduction in performance. If you do not use power tools regularly, consider investing in a plug-in power tool.

When to Charge Your Batteries

As a rule of thumb, charge your batteries whenever you can and keep them from going under 20 percent charge for best performance. On a similar note, avoid recharging them again if you have only used your tools for a short while.

How to Charge Batteries

The best charging practices depend on the type of battery you are using. For optimal battery performance, refer to your tool’s manual. Usually, keeping batteries plugged into a charging base can reduce its life. However, some charging bases protect batteries from overcharging when left plugged into the charger.

Li-ion Batteries

A lithium-ion battery offers the ultimate convenience and performance. They are able to be charged whenever necessary to ensure you are always ready to complete the task at hand. No need to wait for the batteries to fully discharge.

For best results, do not charge your Li-ion batteries to 100 percent charge. They run best and have the greatest longevity when they are under 90 percent charged. Similarly, Li-ion batteries provide the best performance when they are over 20 percent charged. If you notice your tool slowing down, it is time to recharge your battery.

Once it has been fully charged, do not leave it in the charger for a prolonged period of time. If you are ready to store it, charge it to about 30 to 40 percent before putting it away. If your battery does not have a built-in meter, you can use an external battery indicator to check if you have low battery life.

NiCd and NiMh Batteries

NiCd and NiMh batteries have similar best charging practices. However, NiMh batteries have a higher capacity and no noticeable memory effect. NiCd batteries have a “memory effect” that makes the battery hold less charge if partially discharged before charging.

For example, if you use your battery every day and use only 30 percent of its full capacity before recharging it, it can “forget” it has an additional 70 percent capacity. The batteries will still work but only at 30 percent capacity.

Charge the batteries when you notice a weaker performance in your power tool. Avoid completely draining the battery on a frequent basis. Since nickel-based batteries lose their charge quickly, many manufacturers recommend draining the battery before storing them for extended periods of time.

Why You Should Have a Backup Battery

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Using a backup battery when your battery is running low can be an excellent way to improve the battery’s power and life. When your power tool’s performance is weak, charge it and use a backup battery if you do not have the time to wait for the battery to charge.

Completely discharging your batteries is not recommended. For this reason, it is important to have a backup battery on hand. Avoid delays in your project’s timeline by having a backup readily available when one battery starts to slow down your work.

How to Store Batteries

Getting the most out of your cordless power tools means treating every component with the utmost care. Store your batteries in a cool, dry, and dark place. Before storing them, ensure they are at about a 30 to 40 percent charge. Some nickel-based tool manufacturers may recommend completely discharging batteries before storing them.

If you are at the worksite, store your loose batteries in separate compartments, preferably in a padded case or bag to keep them away from light and moisture. At home, keep your batteries stored in their cases and away from dust and sources of ignition to reduce safety risks.

Be sure to cover their plastic terminals with their cap. Terminal caps protect batteries from water damage, scratches, and short-circuiting. To reduce the risk of fire, keep conductive metal objects away from terminals and the battery

Batteries may need to be recharged before using after being left idle for long periods of time. Batteries drain even when not used. NiCd batteries can lose a noticeable amount of power during the first few days when not in use. Li-ion batteries are better at preserving battery power.

Keep Batteries Dry

Excess humidity and moisture can significantly affect the performance of rechargeable batteries. While working in a light drizzle will not have much effect on battery performance, working in a heavy downpour for hours on end can increase the risk of electric shock and kill the battery.

Storing batteries in overly humid environments can lead to terminal corrosion. Corrosion can significantly reduce battery life and performance. Moisture can get through the protective housing and damage the battery. Do not use a battery that has been immersed in water or displays signs of water damage.

Keep Batteries Cool

Extreme temperature fluctuations, especially extreme heat, can damage the battery. Do not store your batteries in locations that could increase their risk of overheating. In addition, do not charge them outside in extremely cold temperatures. Batteries have an ideal temperature range for optimal performance.

When at an outdoor worksite, do not expose batteries to direct sunlight for an extended period of time. In addition, avoid storing power tools and batteries in a car when temperatures are high.

After overheating, batteries may not be able to be charged unless they reach a specific internal temperature. Before you try to charge batteries that have been in direct sunlight, move them to a cool and dry place first and leave them there for a few hours.

When to Replace Batteries

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Rechargeable batteries can last about three years or longer depending on how you use and store them. Over time, however, you will have to replace your weak battery with a new battery. So, how do you know when it is time to ditch your under-performing battery?

If your battery takes an unusually long time to charge, it may need replacement. If it does not last long after a full charge, replacement is necessary. Some power tools can show users the status of their batteries on a display.

How to Check Power Tool Batteries

If your cordless power tool is not able to hold a charge or loses power quickly, you may need to replace it. Power tool batteries degrade with age and use. Battery performance can also be affected by battery damage. A multimeter can be used to determine if your battery needs replacement.

How to use a multimeter:

  1. Plug in the battery and charge it for an hour, at least. Unplug the battery before testing it.
  2. Touch the multimeter probes to the battery terminals. Touch the negative probe to the negative terminal and the positive probe to the positive terminal.
  3. Look at the voltage indicator on the multimeter. Completely charged batteries test at least 1 volt higher than the voltage found on the battery.
  4. If the voltage reading is at or below the listed rating on the battery, you need to replace the battery.
  5. If the multimeter displays a high voltage, but the battery is not able to hold a charge, it may need repairing.

How to Dispose of Batteries

Rechargeable batteries should not be disposed of in your household garbage or recycling bin. Toxic metals in these batteries can increase the risk of fire and harm our ecosystem and health if disposed of improperly.

Turn to recycle companies that can help you dispose of the rechargeable batteries in a responsible manner and prevent these chemicals from ending up in streams and landfills. Contact home improvement stores and battery recycling locations that partner with Call 2 Recycle, a nonprofit organization.

Call 2 Recycle provides battery drop-off bins across the country. Find a drop-off bin near you using their online map. If you do not have a bin near you, contact your city hall or local waste collection and recycling companies. In some cases, your county or neighborhood may provide pickup services at certain times and locations, so that you can recycle old batteries.

Shop Rechargeable Batteries and Cordless Power Tools at Wilco

Wilco Farm Stores provides you with a wide selection of rechargeable batteries and cordless power tools. Cordless tools provide you with the ultimate convenience and flexibility to tackle your everyday tasks. Shop Wilco Farm Stores for high-performance tools at competitive prices today!