Nope, and I recently experienced this fun first hand.
My work desk has a built-in USB-3 C port, and says it supports USB Power Delivery. The desk is plugged into the wall. Excellent, I can use that port to charge the MBP, right? No! Plugging into that port will cause OS X to believe it's connected to a power supply — so the battery is "charging" according to the OS. Even more fun, is after leaving the laptop in this setup for some time: there's no visual indication in OS X that the battery is about to die and AFAICT, OS X would happily take no action, since it believes it's connected to a power supply¹.
Why? Because the USB "power delivery port" only delivers 10 W. (A normal MBP power adapter, connected to a wall, can deliver like 80 W. How much the laptop needs is dependent on use, but in my case, it's >10 W.) And AFAICT, the desk is compliant with the letter of the spec; USB PD ports are allowed to negotiate whatever power they can deliver; it just allows a device to draw as much as possible/needed, but doesn't guarantee any max rate.
Why anyone puts a max 10 W port on a desk basically hand-tailored for the SV 4-ft desk open office "experience" is beyond me, though.
> there's no visual indication in OS X that the battery is about to die and AFAICT, OS X would happily take no action, since it believes it's connected to a power supply.
AFAIK, macOS is aware of three different states: 1) no power connected, 2) connected to power (but not charging), 3) charging battery.
2) is indicated by the black background of the battery charging icon, and 3) is indicated by a white background of the battery charging icon.
In the case where the power source can't deliver enough energy for charging (in your case), it is in state 2); and I'm pretty sure macOS always takes action when the battery is about to die unrelated to the state. It'll backup the RAM when the laptop's battery level is dangerously low and shut off itself, and will be restored later.
So, you're correct, and I actually did not know this when I wrote the post you've replied to.
But the point still stands: regardless of which of icon 2) or 3) you get, it still isn't going to alert you to the issue: both are normal icons. 2) appears during a full charge, since then you are also not charging, but connected to power. That is, regardless of 2) or 3), both icons also appear during a normal, actually charging charge cycle, so neither indicates an issue.
> I'm pretty sure macOS always takes action when the battery is about to die unrelated to the state
As I recall it, it was awfully close. But that's not to say that there wasn't still time, and that the OS couldn't have acted. (I didn't drive it to empty to find out!) So, it could be that I'm wrong on this point.
> Why anyone puts a max 10 W port on a desk basically hand-tailored for the SV 4-ft desk open office
If the people are the same, you have answered your own question. Open Offices are not a bright idea in the first place; not sure why you would be expecting anything other than similar ideas :)
That sounds like an issue with the Mac or MacOS mainly. I have a ThinkPad which charges over USB-PD, but if it can't negotiate 45W with the charger, it doesn't show it is connected to AC.
>Why anyone puts a max 10 W port on a desk basically hand-tailored for the SV 4-ft desk open office "experience" is beyond me, though.
Seems simple to me: it costs a lot less to put a cheap, crappy 10W port there, and then they can advertise that their overpriced desk has this fancy feature. The idiot managers at tech companies (probably non-technical HR types) who make the purchasing decisions don't know any better.
My work desk has a built-in USB-3 C port, and says it supports USB Power Delivery. The desk is plugged into the wall. Excellent, I can use that port to charge the MBP, right? No! Plugging into that port will cause OS X to believe it's connected to a power supply — so the battery is "charging" according to the OS. Even more fun, is after leaving the laptop in this setup for some time: there's no visual indication in OS X that the battery is about to die and AFAICT, OS X would happily take no action, since it believes it's connected to a power supply¹.
Why? Because the USB "power delivery port" only delivers 10 W. (A normal MBP power adapter, connected to a wall, can deliver like 80 W. How much the laptop needs is dependent on use, but in my case, it's >10 W.) And AFAICT, the desk is compliant with the letter of the spec; USB PD ports are allowed to negotiate whatever power they can deliver; it just allows a device to draw as much as possible/needed, but doesn't guarantee any max rate.
Why anyone puts a max 10 W port on a desk basically hand-tailored for the SV 4-ft desk open office "experience" is beyond me, though.
¹and, technically, it is.