I put the kb in our conservatory for hours, and the charge went up to 70%
But its now at 23%, if you can't get a constant light supply for this kb then don't buy it imo.
If you have a unobstructed source of light from a window - fine, my desk is in the corner of the room though. A desk lamp that can be angled would be good too.
My ceiling spotlights have no effect whatsoever and my bedside lamp has no effect.
If you don't have unobstructed source of light do yourself a favour buy another wireless kb.
I do not understand the concept of this kb, a ordinary wireless kb can run on the same set of batteries for 3 years with moderate use. This k750 also has a internal battery...which will need to be replaced in a couple of years. What problem this kb is solving I do not know.