Apple Explains Why You Might See 'Not Charging' When a Mac is Plugged In
If you have a Mac and have seen a "Not Charging" warning when plugging it in to power, Apple last week released a support document that explains why.
Macs running macOS 10.15.5 or later have a Battery Health Management feature to preserve the life of the battery, and occasionally, the Battery Health Management option will cause the Mac to pause its charging for calibration purposes.
Depending on its settings, your Mac might temporarily pause charging to help calibrate battery health management, a feature designed to improve the lifespan of your battery.
Apple says that when Battery Health Management is activated, "Not Charging" could be displayed and the charge level might be lowered temporarily, which is a normal function of the feature. Charging to full will resume based on usage habits.
When battery health management is turned on, you might occasionally see "Not Charging" in the battery status menu of your Mac, and your battery's maximum charge level might be lowered temporarily. This is normal, and it's how battery health management optimizes charging. Your Mac resumes charging to 100 percent depending on your usage.
Battery Health Management features are available on Mac notebooks that have Thunderbolt 3 ports and that run macOS Catalina 10.15.5 or later. The option improves the lifespan of a Mac's battery by reducing the amount of time that the battery spends at a maximum charge, which can cut down on chemical aging.
Battery Health Management works based on the battery's temperature history and charging patterns, so if you often leave your Mac charging overnight after using it during the day, the Mac might charge up to around 85 percent and sit there for a bit before charging to full ahead of when it's needed in the morning.
If you use your Mac while Battery Health Management is active, you might see the "Not Charging" warning that Apple mentions. Battery Health Management is enabled by default, but it can be turned off by checking the Battery Health Management option in the Energy Saver section of the System Preferences app once macOS Catalina 10.15.5 or later has been installed.
There are some other reasons that Mac users might see the "Not Charging" warning, such as when the Mac isn't getting enough power to charge the battery. In these situations, Apple recommends people follow the steps in its support document covering charging with a USB-C power adapter.