How can I charge powerbank that has single C-type in/out from MacBook? I’m using Xiaomi Power Bank 3 which has following sockets:


USB-A type low output
USB-A type high output
USB-C type power delivery input/output up to 45W


It usually works fine, I can use MacBook charger to charge the power bank and the power bank can charge MacBook fine.

The problem is, I cannot figure out how to charge power bank from MacBook. The use case will be Charger → Macbook → Power Bank, which I expected to charge both devices, but if I connect like that, the power bank seems not to be charging.
If the macbook usb-C port is not rated to provide what the powerbank demands then it will not negociate and deliver power.

As you say the macbook charger will charge the powerbank correctly and the powerbank will charge the macbook, then the issue is the rated output of the macbook USB-C port.