watchOS 9 was presented alongside iOS 16 and macOS Ventura at the opening keynote of WWDC22. Since then we are already in the second betas for developers of all these operating systems. Many of the features that were introduced are now available to developers and will be available to the general public when Apple launches public betas in a few weeks. One of the novelties of Watch 9 is incorporation of a battery recalibration system for the Apple Watch Series 4 and 5. Thanks to him battery life estimation will be much more accurate than in watchOS 8.
Apple Watch Series 4 and 5 will improve battery life estimates in watchOS 9
In iOS 15.4 Apple also incorporated a similar battery recalibration system for the iPhone 11. Thanks to this system the device is able to recalculate and optimize the battery level, in addition to offering more accurate battery life data, which is also key when considering a change of device or even battery.
After updating to watchOS 9, your Apple Watch Series 4 or Series 5 will recalibrate and then estimate its maximum battery capacity more accurately.
The same is going to happen with watchOS 9. According to the notes of the new operating system from Apple which is in beta mode, Apple Watch Series 4 and 5 will recalibrate their batteries when they first start up. Once the calibration is done, watchOS 9 will display the maximum capacity estimate more accurately, getting closer to the actual data.
This process will be automatic and the user will be able to consult the final result, although he will not be aware of the internal process that takes place. What we do know is that the process could take a couple of weeks, just as it did with iOS 15.4 and the iPhone 11 a few months ago.