Unable to charge Macbook Pro from a power bank.

No, higher power is not all you need.

Whatever substitute device you choose must use USB-C Power Delivery Protocol, and negotiate over the DATA portion of the USB-C charge cable. That charge cable contains low speed data as well as power conductors.

You can connect the entire power output of Niagara Falls, but if you don't negotiate with USB Power Delivery Protocol, your Macbook Pro will not charge.

The simplest way to shop is to look for a device that claims to support 15-in MacBook Pro 2018.

Just asserting a voltage against the power input is not adequate to charge a complex device like a MacBook Pro. The computer is in charge of the entire process.

Charging a USB-C MacBook Pro requires a device that supports USB-C Power Delivery Protocol. The computer and the device negotiate from the list of possible power levels and voltages the smart charging device claims it can deliver. If an acceptable set can be selected, the computer initiates charging.

MacBook Pro typically wants to have a USB-C Power Delivery device that claims it is capable of sending over 20 Volts DC at over 3 Amps to initiate charging.

fsoc wrote:

I'm using 15-inch 2018 Macbook Pro (16 GB RAM, Intel Core i7, 512 GB SSD) and macOS version 12.1 Monterey. I tried to charge my mac with Mi power bank (20000mAh); this model: https://www.mi.com/ph/20000mAh-mi-power-bank-2c/specs/

However, I was unable to change it. It showed "not charging".

Can someone tell me why this happens? Is it because only specific power banks work with my model of mac? If so, I'd like to know the power banks that would work.

Thanks!

Hmmm.

What happens if you bypass the 'power bank' and charge directly using the Magsafe or USBC...(?)

Did you contact Support for your third party device..

see Support https://www.mi.com/ph/20000mAh-mi-power-bank-2c/specs/

service.ph@xiaomi.com