How to Restore a NiCad Battery

Written by deb katula
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How to Restore a NiCad Battery
Yoy can repair NiCad rechargeable batteries by removing dendrite crystals. (battery image by KtD from

As you use nickel-cadmium (NiCad) rechargeable batteries and continuously recharge them, they hold less and less of a full charge over time. Within the rechargeable batteries a dendrite crystal substance, also known as battery charge memory, builds up and decreases the charge capacity. Eventually, when the rechargeable battery no longer holds a charge, the dendrite crystals have built up. To repair NiCad rechargeable batteries, you need to remove the dendrite crystals using an electric current.

Skill level:

Things you need

  • Dead rechargeable NiCad battery
  • Trickle charger
  • Digital multimeter or battery tester
  • Protective eyewear
  • Protective gloves
  • Long-sleeve shirt

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  1. 1

    Locate the black and red clamps on the trickle charger.

  2. 2

    Test the NiCad rechargeable battery to make sure it is fully discharged.

  3. 3

    Locate the positive and negative ends of the NiCad rechargeable battery.

  4. 4

    Protect your eyes, hands and skin before beginning the rechargeable battery "jump start" process. This is a dangerous and hazardous procedure.

  5. 5

    Hold the black clamp on the negative end of the battery.

  6. 6

    Tap the red clamp on the positive end of the battery one or two times. Sparks may crack from the end of the battery.

  7. 7

    Immediately hold the red and black clamps on the battery for 1 to 3 seconds only.

  8. 8

    Use the battery tester or multimeter to determine the battery charge.

  9. 9

    Repeat the process until the battery is fully charged.

Tips and warnings

  • Do not overcharge the battery or it may explode, catch fire or spray acid.

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