An NiCd battery is short for "nickel cadmium" battery. It is a type of rechargeable battery that is often used in power tools, such as cordless drills. Just as nothing lasts forever, including batteries, you will eventually need to replace the battery. It is important to recognise when to replace the battery, and how to obtain the right replacement.
Why Replace the Battery?
When the cordless drill battery will not keep a charge, you should replace it. But before getting rid of the present battery, make sure that it's not able to be recharged. Remove and charge the battery, and place it back in the cordless drill. Use the drill until the battery is discharged down to 1 volt per cell, while checking to see if the battery gives you the amount of usage that it should. If not, charge the battery and use it twice more. If the battery is not recharging to 100 per cent of its power, replace it.
When you replace the drill's battery, the main issues are obtaining a replacement with the correct amperage, voltage and size for the drill. You can easily do this by writing down the battery information, by looking either on the battery itself or in the drill's owner's manual. Or you can simply remove the battery and take it with you to the store and obtain an exact replacement.
Short Memory Syndrome
One quality of an NiCd battery is that an older battery loses it charge faster than a new battery does. This is called the "memory effect" or "short memory syndrome," where the battery itself thinks that it is charged at 100 per cent when you recharge it but is actually not, and the battery stops recharging before it is full. When you use the battery in the drill, the drill loses its power faster than before. This is caused by cadmium crystals forming inside the battery.
You should never keep using the cordless drill until its NiCd battery is fully discharged, or the battery sustains damage. A common tip to help avoid short memory syndrome with the battery is to use the drill until the battery power is totally exhausted and then recharge the battery. This may cause damage instead, and a better idea might be to use the drill until the battery power is low, but no lower than 1 volt. Also, to help preserve the battery life so you won't need to replace it prematurely, store the battery away from extreme heat and don't overcharge it by storing it in the battery charger. When the battery is fully charged, remove it from the charger.