How to Reverse Memory Effect in NiCad Batteries

Updated February 21, 2017

NiCad batteries are most often used in appliances, games and tools requiring the use of rechargeable batteries. As NiCad batteries are regularly charged, used and discharged, "memory" becomes built up. This "memory" consists of dendrite crystals that build up within the NiCad battery. As these dendrite crystals build up, the NiCad battery will hold less and less of a full charge. Once the battery "memory' is full, the NiCad battery will no longer hold a charge. Erasing memory in NiCad batteries will enable a dead rechargeable battery to hold a longer charge, just like new.

Locate the positive and negative ends of the dead NiCad battery. The positive end will be raised, and the negative end should be flat.

Test the battery using the battery tester to ensure that it fully discharged.

Protect yourself during this procedure by wear safety goggles, gloves, and a long sleeved shirt.

Begin recharging process by holding the black clamp of the 12 volt 5 amp AC DC on the negative end of the battery.

Tap the positive end of the battery with the red clamp, 2 or 3 times. Sparks may shoot from the end of the battery.

Hold the red and black clamps on the battery for no longer than 2 seconds.

Release the clamps and test the charge on the battery.

Repeat process if necessary until the battery is fully charged.


Always protect your skin, eyes and hair during this potentially hazardous process. This is very hazardous process that is best performed by someone familiar with working in electricity.


Do not overcharge as battery can catch on fire, explode, or spray acid if mishandled. Individuals attempting this process need to understand the danger and understand that they perform the process at their own risk to injury and damage to self, property and others.

Things You'll Need

  • Long sleeve shirt
  • Protective gloves
  • Safety goggles
  • Fully discharged dead Ni CAD batteries
  • 12 volt 5 amp AC DC charger
  • Battery tester
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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.