The Natural Philosopher wrote:
On 01/03/2020 08:53, Jeff Layman wrote:
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.

Probably Nicd then



Id have said NiMH. I find NiMH cells / batteries not only hold a charge
for a long time but NiCds dont. Ive some cheapish NiMH cells I made into
batteries around 2001 /2 which are still good. I check them perhaps every
couple of months or so, sometimes top them up ( they are for amateur radio
transceivers), and they seem fine.

Conversely, when I used to use NiCads, they died if you stored them and
didnt charge them before they €˜reversed themselves- sometimes within a
month.