How to Recondition a NiCad Battery

Updated February 21, 2017

Nickel-Cadmium (NiCad) batteries are used in appliances, games and tools requiring the use of rechargeable batteries. Reconditioning NiCad batteries, lengthens their expected lifespan, saves consumers money, and keeps batteries out of landfills. As these batteries are regularly charged, used and discharged, "battery memory" becomes built up in the form of dendrite crystals. When NiCad batteries start to internally crystalize, the battery will hold less and less of a full charge. Erasing memory in NiCad batteries will enable a dead rechargeable battery to hold a longer charge, just like new.

Find the positive and negative ends of the NiCad rechargeable battery. The negative end is flat and indicated by a minus sign, and the positive end is raised and indicated by a plus sign.

Test the NiCad batteries using a multimeter or other battery tester to make sure the NiCad batteries are fully discharged prior to beginning the restoration process. The battery can be fully discharged by using it until it has worn down or by using the discharge function available on some cameras and appliances.

Put on all recommended safety gear, including eye goggles, insulated gloves and a long-sleeved shirt.

Begin the reconditioning process by holding the black clamp from the 12-volt battery charger in place on the negative end of the NiCad battery.

Lightly tap the positive end of the battery using the red clamp from the battery charger. This could cause the NiCad battery to emit sparks, and is a part of the process of reconditioning the NiCad "battery memory."

Place and hold the black and red clamps on the battery for a maximum of 3 seconds and then release both clamps. Take care not to touch the black and red clamps together.

Test the NiCad battery with a battery tester or digital multimeter to see if it has been fully recharged and reconditioned.

Repeat the NiCad battery reconditioning process until the battery is at or near a full charge.


The reconditioning process is best performed by someone who is familiar in electrical work.


This is a hazardous process. Completely protect your skin, eyes and hands before starting the NiCad battery reconditioning process. Overcharging the battery can lead to the battery catching fire, exploding, and/or spraying battery acid.

Things You'll Need

  • 12-volt battery charger
  • Safety goggles
  • Insulated gloves
  • Battery tester or digital multimeter
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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.