Apple in iOS 14 added an Optimized Battery Charging feature for the AirPods, which is designed to preserve the battery of the AirPods to maximize longevity.
The new AirPods charging feature lets the AirPods learn a person's daily charging routine, and will wait to finish charging past 80 percent until they're needed.
So, for example, if the AirPods are charged at night while you sleep, the optimization feature might charge them up to 80 percent right away, but wait until an hour or so before you wake up to charge the remaining 20 percent.
Apple uses a similar battery health optimization system for iPhones and Macs to extend the total battery life of the devices. Avoiding topping up a lithium ion battery continually while it sits on the charger reduces the amount of time that a device spends at maximum capacity, and over a long period of time, this better preserves the health of your battery.
Optimized Battery Charging was added to the iPhone in iOS 13 and a similar Battery Health Management feature was added to macOS in macOS Catalina 10.15.5.
Top Rated Comments
I turned on the battery optimization feature on my iPhone a year ago and saw it activate ONCE. I have NEVER, EVER used my phone between 2am and 6am during a weekday, and ALWAYS have it plugged in to charge, yet Apple hasn't figured that part out... I really am disappointed with their machine learning for a device that should be much easier to learn as far as charging habits go.
I'd side with the manual toggle as well. Let me just create a schedule myself in some advanced settings, so that users that care can make it work while you fine tune your ML with everyone else.