How to charge a MacBook Pro through USB-C from a battery pack?
I read that it is possible to charge or draw power from a USB-C port on the new MacBook Pro. How do you control which direction the power will flow in?
Thanks.
I came across this question while also looking for the ability to select the direction of power flow to/from the MacBook so that I could charge the power bank. I don't have an answer to your question, but I hope some of this testing is helpful for others that come across this question.
I don't believe Grant Bennet-Alder's answer is 100% accurate. I can plug both my USB-C Nexus 6P adapter (5V/3A/15W) and USB-C power bank (5V/3A/15W) into my MacBook Pro (late 2016). Both chargers will charge the MacBook, albiet at very slow rates. Sometimes the net amperage is still negative, depending on the draw from running applications. When plugging in my Nexus 6P directly into the MacBook, it charges at the full USB PD spec (5V/3A). The Nexus 6P offers the ability to supply power over USB-C, when selecting this the Nexus 6P will stop charging but does not begin charging the MacBook.
I am attaching four images relating to four different charge states. In order: not charging, charging from power bank, charging from Nexus 6P adapter, and charging from the Apple 60W MacBook Pro adapter. I tested all states while running my usual Chrome tab load (14 tabs), the Slack desktop app, and one iTerm instance. I am using the Battery Monitor (v2.3) app to display the data, it is available in the App Store.
Not charging:
Power bank charging (5V/3A/15W):
Nexus 6P adapter (5V/3A/15W):
Apple 60W MacBook Pro adapter (20V/3A/60W):
