Sooooooo, I had re-arranged some cables, and positioning, and the peripherals that were plugged into my Thunderbolt 3 dock the other day (to be faiiiiiiiiiiiir…), and noticed today that my MackBook Pro was not charging.
I have optimized battery management set up and know that it can hover around 80% charge before charging back up fully again. I rarely use it off the power adapter because I use the external hard drives very extensively to organize and back up my porn collection, er, my Lightroom catalog, as one does.
All day, I watched its charge slowly lowering past 80%. I reset NVRAM, and SMC, as normally suggested. Kept dropping over time to 60%.
Looked up how to force MacOS to charge the battery while connected to TB3. An existing option to force charge didn’t exist — it requires the Mac to be plugged into a power adapter.
The Mac was plugged into its TB3 cable as normal. Hard drives were fully accessible. Everything was fine.
At 32% charge I gave up and looked at the TB3 dock to make sure everything was plugged in tightly. Everything was fine, apparently, EXCEPT the TB3 cable. I had re-plugged it into the dock’s second TB3 port the other day — the data port and not the host port that is clearly labeled “Computer” which provides, among other things, 87 watts of power.
So, to conclude this episode of Adrian’s Technology Brain Farts, I plugged the cable into the correct port on the dock and my laptop is now charging normally.
I’m a dummy.