The Medway Handyman wrote:

Most solar stuff doesn't run directly off sunlight these days. They have
rechargeable AA batteries which are charged by the sun, then used to run
the lights/pump/whatever.

One of the models I've been looking at has this in its description (bad
English and all):

"The water pump will not working without sunlight, it will restart within
three seconds once the sunlight re-appear."

Old technology, then?

If you can get one where the solar cell is on a separate cable, that can
be placed in direct sunlight.

Annoyingly, that same model is like that: http://tinyurl.com/n4bcgw8

Thanks, Dave.

Bert