Force Your MacBook to Only Charge up to 80 Percent (and Why You Should)

"Your Mac delays charging past 80 percent when it predicts that you'll be plugged in for an extended period of time, and aims to fully charge the battery before you unplug. The idea is to minimize the amount of time the battery is fully charged in a way that you won't even notice."

"One common bit of advice is to only charge your devices up to 80 percent most of the time. Battery University, funded by a consultancy that helps large companies get more out of batteries, suggests this based on its research. So does the National Renewable Energy Laboratory."

"Your Mac is designed to only charge up to 80 percent-at least, under some circumstances. By default, Mac devices learn your charging and usage routines and juice up your battery based on that."

Batteries are chemical devices that naturally wear down with age and use. Research from Battery University and the National Renewable Energy Laboratory recommends charging devices to only 80 percent most of the time to extend battery lifespan. MacBooks include built-in optimization that automatically implements this strategy by learning your charging patterns and delaying charging past 80 percent when it predicts extended plugged-in time, then completing the charge before you unplug. This feature operates by default without requiring user intervention. Users can also employ third-party applications for additional control over charging limits if desired.

Read at WIRED