snip
As I said, you do need to be sure that your clock was designed to work
with a lithium ion cell as they can burst into flames if incorrectly
charged. If you do try it, make sure you get cells with built in
protection modules and don't blame me if your house burns down.

Idiot boy questions for my education : might it have been an "ordinary"
lithium battery - i.e. not rechargeable? Unless the paperwork specified
the "solar" recharged a battery might it have been cheaper for the
manufacturer to stick a non-rechargeable in given the likely long life
with such a device - i.e. well beyond any reasonable claim for a refund
under the Sale of Gods Act?

Would the presence of a charging voltage and current from the clock
(when in bright light) be one test?
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com