Clearing out the shed I came across my old 4.8v Challenge Extreme
powered screwdriver, which I hadn't seen for at least 6 years (I use my
Hitachi drill/driver instead). When I opened the box and took out the
screwdriver I accidently touched the trigger and was amazed when the
motor turned. I though it might be the dregs of a charge in the cells,
but I tried again and it turned. In fact, it was not possible to stop it
turning by gripping the shaft.

I have no idea what brand NiMH cells were used in this cheap screwdriver
(Argos), but for the four of them to retain a good charge for 6 years
seems very unusual to me.

--

Jeff