PSA: If your 2016+ MBP is losing power while connected to the AC adapter, make sure your USB-C cable is rated for a high enough wattage

[mossme89]

Just a quick PSA that will hopefully help anyone in this position in the future.

The problem:
-Your USB-C Mac is draining while it's connected to the AC adapter

The likely issue:
-If you're using a non-OEM USB-C cable, make sure it's rated for the wattage of your power adapter. In my case I have a 16-inch MBP that was only charging at 60W/96W.

To check the wattage being drawn, go to
Apple logo -> About this Mac -> System Report -> Power -> AC Charger Information

 

[jerryk]

This is standard for all USB-C charging. The charging is smart. The charger, device, and cable negotiate the highest rate of charging they all can support. If the cable is not emarked (has chip) for 100W that rate will be limited to 60W. Also, if the charger can only provide a lower amount of power AND the device can charge that will be the limit. But, if the device cannot charge at this low power the device will not charge, so using a phone charger to try to charge your MBP may not work.

Personally I carry a USB-C 60W travel charger as a spare. They are small and have enough power to charge my phone, iPad Pro, or even slowly charge my MBP 16" in a pinch.