I cracked open an el cheapo cordless power tool set at the weekend. I put
an uncharged battery into the charger an after a few seconds the charger
indicated charging was complete. The battery was still uncharged. I then
tried with the other battery and got the same problem.

I tried again today, this time using the charger inside the house instead
of an unheated outbuilding. Initially I got the same problem so rang the
service center up and they said the charger must be faulty and they'd send
a new one.

However, after a few hours - now the charger has come up to room
temperature (from around freezing) - it seems to be working fine and
charging the batteries

Have others experienced this, or does it sound like a fault? There's no
operating temperature in the instructions, although the charger does say
for indoor use only (and I'd claim my outbuilding is still indoors!).

Thanks,
Piers