My Dell laptop has two little battery icons on its F2 and F3 keys, one with an electric bolt (F2), and one without (F3). It appears that these little battery Fn-keys enable and disable battery charging.
I found this out inadvertently when I tried pressing them both and got no UI feedback... then later I noticed my battery status icon was low, and the tooltip was reporting "Battery plugged in (not charging)".
So I pressed Fn-F2 (the one with the bolt) and the icon indicated it was charging once again.
This was totally trial-and-error, and there was little indication as to what I was supposed to do. In fact, there are dozens of "Plugged in, not charging" results on Google, and I wonder how many are due to this simple mistake.
Are these standard buttons, or are they Dell proprietary? Is there typically more UI feedback for the enabling/disabling of battery charging?