How to Rejuvenate a Rechargeable Battery for a Power Tool

Avoid buying new batteries by reviving your rechargeables.

Avoid buying new, expensive rechargeable batteries by rejuvenating your old ones. Rechargeable batteries are used in electronic devices and in power tools as well. Overcharging and temperature changes can contribute to a battery losing its ability to hold a charge. Learn how to revive your rechargeable batteries and continue using them in power tools or other electronics.

Things You'll Need

• Battery charger
• Multimeter
• Goggles or other protective eyewear
• Gloves

Instructions

1. Check your battery charger to ensure it is able to properly charge batteries. Check for bent prongs or anything that may be preventing the charger from making contact with the outlet. Replace the charger if you determine that it was the cause for not charging batteries.

2. Use a multimeter or battery tester to "zap" the rechargeable batteries. Hold the black end of the multimeter to the negative, or flat, end of the battery. Maintain the hold on the negative end while you tap the red end of the multimeter to the positive, or raised, part of the battery. Tapping the positive end of the battery causes sparks to fly. Zapping the batteries completely drains them, allowing them to be recharged like new batteries.

3. Repeat Step 2 for each rechargeable battery you wish to revive.

4. Place rechargeable batteries in the charger until fully recharged. Use in power tools or other electronic devices as usual.

Tips & Warnings

• Wear protective eyewear and gloves when zapping batteries.

• Recycle dead batteries when they can no longer be revived.

• Use caution when tapping the battery. Tapping should be a quick, light motion.

• Improperly zapping could cause the battery to explode or catch on fire.

References

• Northwestern University: Using a Multimeter

Resources

• NYC.gov: Home Batteries and Battery-Powered Devices
• "The New York Times": About Batteries: Tips on Longevity and Reviving the Dead