So your window is 20,100... about right.Here are some quick photos I just took to demonstrate. The meter is a cheap one so if it’s flawed, or if the numbers don’t link as nicely as we’d like to charging level for a solar panel, who knows. But interesting for discussion.
Slightly overcast day, windowsill.
Nightstand, LED lamp, at a distance the watches are if I leave it on like this:
Right up against the LED lamp, which I can do if I turn the gooseneck upside down. They get warm that way, though.
...and the CoolFire.
If it says x10, add a 0 to the reading; if if x100, add two 0’s.
For what it’s worth!
Your desk lamp is 5,540 lux. OK.... believable.
On the desklamp bulb: 88,400. Also believable at contact distance.
Your CoolFire is reading 345 lux??? Something is very, very wrong. Are you running it on the USB power? Or batteries? It should be so bright you can't look at it directly. No kidding.