Yesterday my 2017 MBP running Big Sur 11.2 suddenly stopped working. A loud click and that was it. It was connected - like 99% of the time - to a Belkin dockand external monitor. Of course I was a bit in a shock, thinking it was broken.
I disconnected the dock and tried to restart the machine. However after the startup chime nothing happened. Next thing I did was connecting it to the original Apple power supply. And lo and behold my MBP sprang to life again.
It turned out - at least from what I could make up from the highly uninformative graph in the Battery system pref pane - that the battery was empty.
Okay, so no big thing luckily. However, shouldn’t there be some warning - a pop up or something - that the battery nears 0%? Or even better, when there’s less than 10% left?
How comes there’s no such thing on MacOS? And does anybody have a clue why the laptop can be connected to a power supply but still is not charging?
On a side note, this again made me consider buying an M1 Mac Mini. I’ve never been very happy with the 2017 MBP (i7, 16GB). I think it’s overpriced to start with. I must keep it though, as I do need a laptop for my job (client work out of the office, which could happen).
The laptop battery could drain while plugged in if the charger doesn’t have enough capacity. Not sure how much power the dock (monitor?) is sending to the laptop. You didn’t say what screen size MBP you have but if it’s the 15” model, it needs a pretty good size charger (IIRC, it comes with an 87W charger).
My experience has been that I receive a low battery alert when I get (somewhere) below 10% remaining. Not sure if that is default macOS, iStat Menu, or Fruit Juice popping up the notification though.
What @JoePreiser said. What’s tricky is that if your battery is connected but still drains faster than it’s recharged because of lower output, the Mac will still think it’s charging despite the fact that it’s depleting, because it’s connected to a power source. I believe there are no notifications in that case because, well, they wouldn’t make sense (no point in warning you you reach 10% if you’re truly charging)