Nicad

Trademarked name for a Nickel-Cadmium battery owned by SAFT America Inc. Nicad is a rechargeable battery, made mostly of of nickel and cadmium. A primary problem with nickel-cadmium batteries was that they needed to be completely drained of power before they could be recharged.
Known as a memory loss or memory effect, if the battery was not completely drained, once the battery reaches its last low level, the battery would go dead, assuming that no power was left.

Issues and information on Nicad batteries.

Nicad Batteries are a well known and understood; the Nicad is used where long life, high discharge rate and economical price are important.

Battery manufacturers recommend to slow charge a new Nicad battery for 24-hours before use. This initial trickle charge helps to redistribute the electrolyte to remedy dry spots on the separator that may appear when the electrolyte gravitates to the bottom of the cell during long storage. A slow charge also helps to bring all the individual cells within a battery pack up to an equal charge level because each cell may have self-discharged to different capacity levels during storage

Distinct advantages of today's Nicad batteries are:

Delivers high current output; relatively tolerant of overcharging; withstands up to 500 charging cycles.

Negative attributes of today's Nicad batteries are:

Mature technology with little tolerant of overcharging; withstands room for improvement; cadmium is environmentally troublesome; noticeable memory effect.