I’ve got this one in the conservatory, which is east facing I think so only gets the morning/early afternoon sun. The light is also filtered by the thin glass of the conservatory roof.
It seems to work OK – I’ve had to take the batteries out to charge them once and it’s low on juice at the moment and has cut out a couple of times. When you do recharge the batterries you have to then shine a torch back on the panels in order to get the light working again.
Not a solid piece of engineering, but sufficient and lets the cats see what they are doing when they climb into the litter trays (or rather me when cleaning them out late at night/feeding them).
This one seemed to have more solar panels than the others, and it is quite bright.
https://www.amazon.co.uk/gp/product/B075K4TP2N/ref=oh_aui_search_asin_title?ie=UTF8&psc=1