Hi
If battery drain on your iPhone is higher than expected after pairing an Apple Watch to it, then it may help to follow these steps (check after each):
If you have not yet done so, update your iPhone and Apple Watch to the latest compatible software versions, starting with your iPhone:
Check which apps are responsible for battery usage:
- Go to: Settings > Battery > under Battery Usage, select the Last 24 Hours tab.
- Address any issues with potentially problematic apps (such as by removing and reinstalling them).
Restart both your iPhone and your Apple Watch, turning both off together and then restarting your iPhone first:
Follow Apple's tips for maximising battery life on your iPhone, as detailed here:
If you have ever (not necessarily recently) previously used the Workout app and/or any third-party fitness, sleep and/or heart rate tracking apps on your watch, check on your Apple Watch to see whether there is an active or paused session within any of them.
- If there is, end that activity from within the app on your Apple Watch (not your iPhone).
- If in doubt, it may help remove any such third-party apps from your Apple Watch, at least temporarily.
Unpair and re-pair your Apple Watch:
Some users have previously experienced battery life issues in connection with using corporate profiles and/or Exchange Calendars. If you are using an Exchange Calendar, one or more of these steps may help:
- Archive your Exchange Calendar for all items before today.
- Remove / delete all old inbox messages relating to calendar invites (accept and decline notifications).
- Create a rule in your Outlook Mail account that moves all future accept and decline replies, immediately upon receipt, into a separate mail folder that does not sync with your iPhone and Apple Watch.
- Check your Exchange Calendar for errors.
Test by changing notification settings and/or by removing watch face complications and third-party apps:
- Turn off notifications for third-party apps and test performance after re-enabling them one at a time:
- Remove watch face complications and monitor performance as you add them back:
- Remove third-party apps from the Dock and/or remove them completely from your Apple Watch and then monitor performance after adding them back, one at a time.
Having tried the previous steps, if your remain concerned that battery life on your iPhone is shorter than it should be, then I suggest contacting Apple Support (remote diagnostics and/or mail-in service may be available, if required), making a Genius Bar reservation or visiting an Apple Authorised Service Provider for assistance: