With watchOS 9, Apple introduces a new power saving mode for the Apple Watch Series 4 and newer models that is designed to extend battery life by disabling or limiting some features and sensors.
In a new support document recently published Apple describes in detail the functions that are disabled or limited when power saving mode is enabled. The following features are listed:
Power saving mode turns off these functions
- Always-On Display
- Heart rate notifications for irregular rhythm, high heart rate and low heart rate
- heart rate measurements in the background
- blood oxygen measurements in the background
- reminder to start training
Power saving mode turns off these features when your iPhone is not nearby
- WiFi and mobile connections
- Incoming calls and notifications
Power saving mode affects these functions
- Calling may take longer
- Apps are updated less frequently in the background
- Complications are updated less frequently
- Siri may take longer to process a request
- Some animations and scrolling may appear less smooth
For safety reasons, Apple says fall detection will also work in the new power saving mode. To enable power saving mode, swipe up on the watch face to open Control Center, tap the battery percentage button, and enable power saving mode.
watchOS 9: New power saving mode for longer battery life
When the Apple Watch's battery percentage drops to 10%, an alert will ask users if they want to enable Low Power Mode. Low Power Mode will turn off automatically when the Apple Watch is charged to 80%, unless you manually turn it on for a set number of days. Apple says users can turn Low Power Mode on automatically when they start a workout, with metrics like heart rate and speed still being measured. Apple notes that if Low Power Mode is enabled without your iPhone nearby and you open an app that requires a data connection, it will restore the WiFi or cellular connection so the app can function properly, which may result in "significant battery drain." (Image: Apple)