Stop Macbook from making sound when plugged in to charge

I have a Macbook Air and whenever I plug in the USB-C cable to charge, it makes a notification chirp to indicate it's charging.

The problem is that this sound comes out audibly, even when headphones are plugged in (unlike other sounds which do come through the headphones), and even when all sounds are muted (other sounds do get successfully muted).

The charging chirp does not seem to follow regular rules governing notification sound effects. How can I plug my laptop in to charge silently?

Solution 1:

Edit: you may find answers here Turning Power Chime Off

Open Terminal, and run the following command:

defaults write com.apple.PowerChime ChimeOnNoHardware -bool true;killall PowerChime

If that didn't work, try:

defaults write com.apple.PowerChime ChimeOnAllHardware -bool false;killall PowerChime

To re-enable it:

defaults write com.apple.PowerChime ChimeOnAllHardware -bool true; open /System/Library/CoreServices/PowerChime.app &