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How to Fix Your Cordless Drill Battery

By Martin Adamovic
Repairing cordless drill batteries is simple.
drill image by Albert Lozano from Fotolia.com

Cordless drills are a great, portable alternative to the classic power drill that has to be plugged into an outlet. A cordless drill lets you move freely in your work space without having to deal with the hassles of tangled cords. Additionally, cordless drills allow you to work where there is no electrical power or where getting power to the work site is a long, difficult process. Although cordless drills are great inventions, they become useless if their batteries stop functioning correctly. Fortunately, you can repair these batteries and get your cordless drill running again quickly.

Identify the positive and negative posts on the battery with a volt meter, and use a piece of tape to label the posts accordingly.

Open the battery case by removing the screws on the outside of the battery case with a Phillips head screwdriver. Organize the screws and any springs or additional items that fall out of the case in a small container.

Remove the battery cells from inside the case by pulling up on them with your hand. Use gloves when touching the battery cells to avoid harming your skin.

Wrap the metal band that lies beneath the battery cells you removed with electrical tape. Avoid touching this metallic piece with your bare hands because it can get quite hot.

Remove the silver piece of insulation from the case and any plastic wrap that is covering the top and bottom posts on the battery.

Test the battery cells with a battery tester, and mark those cells that are not working with a piece of tape so you can repair them later.

Choose one of the battery cells that you marked with tape in the previous step to be repaired. Locate the positive and negative ends of the cell, which can be identified by their flat or raised surfaces, respectively.

Touch the black clamp on the 12-volt power source to the negative end of the cell while touching the red clamp to the positive end. Hold the two clamps in contact with the ends of the battery for no more than two seconds, and remove them.

Test the cell again with the battery tester to verify that the cell has been repaired and will take a charge. If the cell still does not take a charge, repeat step 8 for a maximum of 10 times until the battery holds a charge. If the cell will not hold a charge after 10 attempts, it will have to be replaced entirely.


Things You Will Need

  • Volt meter
  • Electrical tape
  • Phillips head screwdriver
  • Small container
  • Insulated gloves
  • Battery tester
  • 12-volt power source
  • Small red and black alligator clamps
  • Safety glasses
  • Long-sleeved shirt


  • Wear gloves, goggles and a long-sleeved shirt when working with batteries.

About the Author


Writing in both Spanish and English, Martin Adamovic has been covering psychology, marketing, lifestyle and sports since 2009. She has served as a sports journalist for a variety of mobile sports applications in Europe, including General Mobile and Bravo Game Studios. Adamovic holds a B.A. in Spanish and business from the University of Colorado and is currently studying law.