How to Rejuvenate a Dewalt Rechargeable Battery

Updated February 21, 2017

Rejuvenate your Dewalt rechargeable battery by using shock therapy to bring it back to life. Over time, Dewalt battery packs hold less and less of a full charge. Eventually, the batteries die out, holding no charge at all. Rejuvenating your Dewalt battery pack is challenging, but saves you money on a new Dewalt battery pack.

Locate and unscrew the small screws on the Dewalt battery pack. Set the screws aside for later reassembly.

Test each individual cell within the Dewalt battery pack with the battery tester. Use a marker to mark the cells that need to be rejuvenated.

Prepare the first "bad" cell for reconditioning by attaching or holding the black alligator clip to the negative end of the rechargeable cell.

Tap the positive end of the "bad" cell with the red alligator clamp one or two times and then hold for a maximum of 2 seconds.

Release all clamps from the rechargeable battery cell and retest the battery with the battery charger to see if it has been fully charged.

Repeat the process on the same cell if necessary, until it is fully charged.

Repeat this process on all other "dead" battery cells within the Dewalt battery pack.

Replace the rejuvenated battery cells into the Dewalt battery pack case and screw it closed.

Place the rejuvenated Dewalt battery pack on the battery charger overnight.


Use only on nickel metal hydride (nimh) and nickel cadmium (nicad) batteries.


Wear protective goggles, long-sleeve shirt and gloves during this process. Handle with care, if mishandled the battery can catch fire, leak acid or explode.

Things You'll Need

  • Dead Dewalt battery pack
  • Screwdriver
  • Battery tester
  • 12-volt power source
  • Red alligator clamp
  • Black alligator clamp
  • Safety goggles
  • Insulated gloves
  • Long-sleeve shirt
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About the Author

Deb Katula has written and researched for Societe Generale, FIMAT, Nikko Securities, Chicago Mercantile Exchange and Arthur Anderson. She holds an MBA in economics and finance from the University of Chicago; a Japanese language fellowship from Harvard; and a Bachelor of Arts in business/psychology/Asian studies from Augustana College.