M1 MacBook Air: External display powering my MBA M1?!

[guymacpsych]

Hi there! I'm loving my new MBA M1 but I suddenly noticed that when it's plugged through USB-C to my external monitor (ThinkVision Lenovo T27H-20), it shows that it's actually powering my MBA as well. Could this be? Am I damaging the MBA or its battery? And no - it's not connected to a docking station or anything. It's directly connected via USB-C to USB-C to the monitor.
Thanks!

 

[Mr. Awesome]

Some monitors do have USB-C Power Delivery capabilities, so it’s possible that the monitor is charging your Mac. This shouldn’t be any more harmful to the battery than charging it regularly would be.

 

[deeddawg]

Normal function of that monitor.

This is one of the great things with using USBC vs the old magsafe style power connections. Single cable connection for docking or monitor&power.

BTW - you'll also find the USB powers on the back of the monitor likely work with your peripherals.

 

[guymacpsych]

Thanks so much friends!

 

[jdb8167]

If you are going to leave your MBA connected to that monitor for much of its use you should make sure that Optimized battery charging is enabled. I think it is on by default but you should check. It will extend the life of your battery.

 

[guymacpsych]

Legend. Thanks so much. And by charging the MacBook via the monitor and not via the Apple Power Adapter, I'm not hurting my MacBook / battery?

 

[jdb8167]

Legend. Thanks so much. And by charging the MacBook via the monitor and not via the Apple Power Adapter, I'm not hurting my MacBook / battery?

There shouldn't be any problem. Modern charging using USB-C Power Delivery is very sophisticated. Apple's software is designed to work with monitors that provide power over the connection and can ask the Power Delivery connection for exactly the power needed to safely charge the battery over time.

 

[Corncab44]

This is by design and quite useful if your monitor has USB ports on it as well (I imagine all usb-c monitors would have them). Not only will your monitor power your laptop (saving a precious usb-c port), but you can use those USB ports on the monitor instead of a dongle if you need to plug in USB peripherals, like a keyboard.