I am curious if anyone has measured directly or found an authoritative reference that documents at which point the various iPad will display charging and not "not charging" in the menu bar while operating. Apple publishes great information on how it's Computers and Displays will over supply power to select Apple devices well past the normal USB standard, but I can't find iPad specific information.
I presumes this notification is based purely on a set amount of current being detected and not simply a net power surplus (since the load of an iPad can vary based on CPU/GPU, brightness and radio power consumption) calculation.
Best Answer
The iPad manual (page 136) and other Apple documentation (see bottom) are not very specific in this regard meaning...
...they only distinguish between:
Also see the following documents: