The information contained in this document is generalized information on Nickel-Cadmium (NiCad) type rechargeable batteries, such as those used in portable power tools.
This information represents "experienced technical opinions" at the time of publishing and is written as general information and helpful advice for the average product user looking to maximize rechargeable NiCad battery power use and battery life. The information provided is not intended as expert technical statistical data and does not guarantee any item or effect any product warranties.
Memory Effect: NiCad batteries are prone to what is referred to as the "memory effect". This means that if a NiCad battery is repeatedly only partially discharged before recharging, the battery "forgets" that it has the capacity to further discharge all the way down. To illustrate: If a tool operator, on a regular basis, fully charges a NiCad battery and then uses only 50% of its capacity before the next recharge, eventually the battery will become unaware of its extra 50% capacity which has remained unused. The battery will remain functional, but only at 50% of its original capacity. The way to avoid the "memory effect" is to fully cycle (fully charge and then fully discharge) the battery at least once every two to three months. Simply leaving the device in the ON position and letting it run can discharge batteries completely. This will help insure the battery remains healthy. Once discharged, recharge the battery completely according to the manufacturer's instructions.
Battery Lifetime: The average life of a rechargeable NiCad battery used in most portable power tools, operating under normal conditions and care, is generally between 400 to 600 charge-discharge cycles. This translates into approximately four years of battery life for the average portable power tool user. NiCad batteries tend to be heavier, less prone to damage from severe temperature fluctuations, and overall more durable, when compared to similar Rechargeable Li-ion Battery, making them more popular with commercial contractors, who tend to be rougher with their equipment.
As the rechargeable battery begins to die, the user will usually notice a decline in the running time of the battery.
Example: When a battery that originally operated the tool for three hours of use is now only supplying the user with one hour worth of use, it's time for a new battery.
Maximizing Battery Performance: There are several steps that can be taken to maximize the life and performance from the rechargeable battery. Below are some of the most common recommended practices to promote a healthy and longer life cycle of NiCad type batteries.
Break-In New Batteries: New NiCad batteries generally come in a somewhat discharged condition and must be fully charged before use. It is recommended that new batteries be fully charged, fully discharged and subsequently fully recharged approximately two to four times to allow them to reach its maximum rated capacity. To prevent the Memory Effect (see above) keep the battery healthy by fully charged and then fully discharging it periodically.
Keep the Batteries Clean: It's a good idea to periodically clean dirty battery contacts with a cotton swab and alcohol. This helps maintain a good connection between the battery and the device.
Exercise the Battery: Do not leave the battery dormant for long periods of time. We recommend using the battery at least once every two to three weeks. If a battery has not been used for a long period of time, perform the new battery break in procedure described above.
Battery Storage: If you don't plan on using the battery for a month or more, we recommend storing it in a clean, dry, cool place away from extreme heat or cold and away from contact with metal objects. NiCad batteries will self-discharge during storage, therefore it is recommended to break-in the battery again (see above) before returning a stored battery to regular use.
NiCad Battery Charger: It is important to use only the battery charger that is specifically matched to the battery and approved for use by the battery manufacturer. Most NiCad battery chargers are durable and if taken care of normally last the full lifetime of the associated tool. However, there are those rare occasions where the battery charger may need to be replaced with a new one. Since most of these style chargers are draw-dependent, internally-regulated and for the most part non-repairable, the testing of these chargers is not something the average consumer or service center can readily do. If the battery charger is not charging a relatively new battery or for some other reason is suspect, such as the charger suddenly feels unusually cold or unusually warm to the touch during charging, replacement of the charger may be necessary.
NOTE: The average life and discharge recharge cycle data are for reference use only. As explained, there are many and various conditions that can positively and/or negatively influence the outcome of a particular battery actual life cycle.
