MacBook Pro Clamshell Solution Without Power Cable

Clamshell mode, a fantastic feature in MacBook Pro, empowers users to close their laptop lids while still benefiting from an external monitor. This configuration creates a streamlined and spacious desktop setup, making it ideal for individuals in need of a larger display.

Recently, I acquired an external monitor to enhance my work-from-home ergonomics. However, I was disappointed to discover that clamshell mode on my 2021 MacBook Pro M1 wouldn’t function without the power adapter connected. Apple has apparently implemented power-saving measures by disabling certain functions while operating on battery power, which affects clamshell mode.

Despite finding various workarounds, none of them aligned with my preference for simplicity. But today, I accidentally stumbled upon a solution that resolves this issue. While searching for alternatives to the bulky HDMI cable connecting my MacBook Pro to the monitor, I decided to experiment with the slimmer USB-C cable that accompanied the monitor. Remarkably, the clamshell mode works flawlessly even without the power adapter connected! The USB-C to USB-C cable proved to be the ultimate solution, and I’m sharing this undocumented revelation to assist others facing a similar challenge.

Solution: USB-C Cable Unlocks Clamshell Mode Without Power Adapter

As I explored ways to optimize my setup, I made the following breakthrough:

  1. Instead of relying on the traditional HDMI cable, consider using a USB-C to USB-C cable that is compatible with both your external monitor and MacBook Pro M1.
  2. Connect one end of the USB-C cable to the USB-C port on your external monitor.
  3. Connect the other end of the USB-C cable to one of the USB-C ports on your MacBook Pro M1.
  4. Once connected, close the lid of your MacBook Pro. The external monitor will now serve as your primary display while the MacBook Pro operates in clamshell mode.

Conclusion: By utilising the USB-C to USB-C cable instead of the power adapter, MacBook Pro M1 users can now seamlessly enjoy clamshell mode without any limitations. This discovery, although not documented elsewhere, has the potential to help numerous individuals seeking an uncomplicated solution. Enhance your productivity and workspace by implementing this USB-C cable workaround, and experience the benefits of clamshell mode with your MacBook Pro M1 and external monitor setup.

UPDATE [24May23]: Turns out that the USB-C cable is actually powering my laptop & hence the ports are not powering off. So my real purpose of unhooking the power supply (so I can go through the battery power cycle) is still not met with this solution!