Set when your Mac shuts down while using a UPS
Reduce the risk of losing data during a power outage by using an uninterruptible power supply (UPS). In the event of a power failure, a UPS provides power to your computer for a period of time.
Some UPS devices run until their batteries are expended and then shut down. With other UPS devices, you can connect the device to the computer’s USB port and set options for it using Energy Saver.
On your Mac desktop computer, choose Apple menu > System Settings, then click Energy Saver in the sidebar. (You may need to scroll down.)
Click UPS Options on the right.
Select one or more options to determine when to shut down after a power outage. Then use the slider to specify the time or battery level at which the Mac desktop computer shuts down.
If you choose more than one option, the Mac desktop computer shuts down when the first condition is met.