</font><font color="blue" class="small">( Garry, I've heard both ways; best to store them discharged and best to store them charged, and quite frankly, I don't know what's best.
. . . )</font>
Good question Bird. The answer I found in the electronics industry is:
It is best to store the batteries with some juice still left in them. Batteries left to sit on the shelf with little to no charge in them can reverse polarity. [For occasional use batteries] reverse polarity is the primary cause of dead cordless batteries. Once one cell in a chain reverses polarity and goes bad, it effectively makes the whole battery bad.
If you use a NiCad battery a little bit and recharge it, and do this a lot, it will soon turn into a battery that will only support short term use. NiCads will develop a memory of partial discharge and "remember" the recharge state as the low point if done repetetively.
NiMH batteries don't develop memory like NiCads. So they can be partially discharged and plugged back in without having to go through a full cycle. Well, in theory anyway, I still full cycle my NiMH batteries just to be sure.
For my Makita 9.6V tools I have two batteries. I run one to exhaustion and immediately drop it into the charger, taking the one out of the charger and use it until exhaustion. When finished with the project, I test the last battery in use in the drill. Grasp the chuck and try to run the drill, If I can keep the drill from turning, I pull that battery for a charge. Otherwise, I just leave it in the drill. Using this technique I get several years use out of my batteries.
