An important caution on the 'Memory Effect'.
For NiCd cells, the premature voltage drop caused by partial discharge and recharge can be corrected by fully discharging the cell. When a NiCd reaches this premature voltage drop point, it still has significant energy stored, and with proper design can be discharged further, however this voltage drop point looks a lot like an end of discharge knee, and will often trigger low battery warnings.
However there is a significant risk if you are dealing with _batteries_ of cells, meaning multiple cells in series. The direction of current flow associated with discharging a cell is the same as the current flow that would 'reverse charge' the cell. Reverse charging a NiCd cell will cause significant damage to the cell.
When you discharge a _battery_ of cells, there is always going to be one cell that discharges first. The other cells will continue to push current though this cell, reverse charging it and damaging it.
So if you elect to discharge a battery 'all the way', be sure to limit 'all the way' to a reasonable value, or you _will_ damage the battery.
A good charger is critical to battery life. I'd recommend investing in a good general purpose 'smart charger' such as sold for RC car use. Use this periodically to evaluate the condition of your batteries, even if you use your normal tool charger most of the time.
-Jon
