Nickel cadmium (NiCad) rechargeable batteries are used in many electrical devices and you've probably replaced many of your regular non-rechargeable batteries and used NiCads as it works out much less expensive over time. However, it's likely you've read about, or experienced, the problems that can be associated using NiCad batteries; they appear to go dead, even though you may have just charged them. Before you discard your "dead" battery, have a go at repairing it; chances are you can get it working again.
Put your NiCad battery into its charger unit. Leave it to charge. Even if your NiCad battery appears dead, it does take a small charge.
Remove the NiCad battery from the charger as soon as the charger indicates the battery is full. Immediately put the battery into the device the battery powers and turn it on.
Open applications on the device so it operates and uses energy. The more energy you can use quickly from the NiCad battery, the better it gets repaired. The reason the battery appears dead is due to the nickel cadmium crystals inside the battery increasing in size over usage. The larger the crystals the less energy the battery can retain, so it appears to go dead quickly.
Wait for the device to turn off automatically. It's likely to be quick so you don't have to wait long. At this stage you usually consider the battery is completely dead and you recharge it. However, it's not dead; leave the battery for half an hour and it regains some energy.
Turn on your device after half an hour. You should find it powers up so open a couple of applications and let it operate until it stops again. It takes even less time to stop this time.
Repeat the process of leaving the battery for a while and then powering it up. Let it operate each time until it stops. The process is a little boring, but every time you leave the battery and then power up your device, the nickel cadmium crystals are breaking down into much smaller crystals. The smaller the crystals the more energy the battery can retain.
Put your NiCad battery back in the charger once your device refuses to power up. The battery is completely dead, but the crystals are restored to approximately their original size and your battery is repaired. Charge your battery until full. Be prepared to wait a reasonable time as the battery can hold substantially more energy.
Turn off the battery charger as soon as the battery is full and remove from the charger. Use your battery as normal; your device has more power and operates much longer.
Follow the above steps every six to nine months and you get your NiCad battery to last much longer. To increase a NiCad battery's life only charge it once your device stops operating or the battery indicator is at its lowest level. This stops the crystals from enlarging.
When you do ultimately need to dispose of your NiCad battery ensure you take it to a battery recycling unit. Don't dispose of NiCad batteries in your regular trash.