The amateur astronomy site Astromart has a short, informative piece on testing and repacking dead power tool NiCd battery packs. These packs are filled with “Sub C” cells. Taking apart a “dead” pack, you can test the individual cells and replace only the bad cells.

Rebuilding NiCd Rechargable Battery Packs – Link


  • Cordless drills – Improve the battery – Link
  • HOW TO – Revive Nicad batteries by zapping with a welder – Link