3 easy steps how to recondition NiCad batteries

NiCad (nickel-cadmium) batteries are common batteries that are used in many different applications. And learning how to repair NiCad batteries is a valuable skill, as they are very common. From your average power tool to emergency lighting systems, you will find recondition NiCad batteries to be the best choice in batteries due to their ability to provide powerful current surges.

How to recondition NiCad batteries

To recondition your NiCad, you will need some tools:

Safety glasses
Digital multimeter
12v slow battery charger with 10/15 amp setting.
2 long nails
Good quality NiCad battery charger.

For repair of the NiCad Drill battery pack you can refer to our main battery reconditioning guides.

For this method, we are going to give the NiCad battery a 12v discharge and then put it back to work. This will resolve the issue on 9/10 and allow you to fully charge NiCad batteries again. Note: If you are trying to recondition a NiCad battery pack, you will need to either decompose the package or use a power pack capable of supplying 30v in short bursts to the entire battery pack.

Step one: check the voltage and discharge the NiCad battery

Security warning! Be sure to wear your safety glasses / goggles for this step.

Take your voltmeter and take a battery Write this reading for future reference. Now put on your safety glasses and turn on your car’s battery charger. Give yourself enough room to work and wait for a few sparks from the battery. Set the charger to the 10 amp or 15 amp setting. Then put a long nail on each clamp. Now you want to put the negative connector on the negative terminal of the battery, then quickly touch the positive connector on the positive terminal of the battery. Do not hold the connection in place, otherwise the battery may explode. You just want to quickly touch the positive terminal of the battery 5-10 times with its positive connector.


Turn off your 12v car battery charger and take another measurement with your voltmeter.If you don’t see any increase in voltage, try to discharge the battery several more times.

Step two: discharge and recharge cycle

Then make sure the NiCad batteries are discharged (do not discharge the NiCad batteries too deep, otherwise it could damage the battery). Put them back in the appliance and download. Then you will want to charge them with a good quality NiCad charger for as long as necessary. It is important that NiCad batteries have been fully discharged and then fully charged, this should reset the memory effect and give it a large capacity again.

Step three: discharge the NiCad battery and freeze it

After fully charging and discharging NiCad batteries, before recharging them, you will freeze them. Seal your NiCad batteries in an airtight zippered bag and place them in the freezer. Leave them at least 4 hours before removing them again. Once you have removed the NiCad batteries from the freezer, it is important that you give them time to defrost. I recommend at least 6-8 hours at room temperature just to make sure they’ve completely thawed.

Now put them back in the charger and fully recharge them. After this, you should see a significant increase in battery performance. And it should save you the cost of replacing them for a longer time.