Amphetamine Keep Your Macbook Awake In The Clamshell Mode Without A Power Adapter
Although there is a workaround, which requires you to change the default properties (pmset – power management settings) of macOS to deal with this situation, we do not recommend going that route. Rather, we recommend using an alternative approach, which is to use a utility that bypasses this restriction. You can find several such utilities on the internet that enable you to use your MacBook in the clamshell mode without having it connected to power all the time....