BatteryPhone

BatteryPhone lets you monitor the battery levels of your phone and Apple Watch from a single extension. It supports watch complications with automatic updates, shows charging status and percent in real time, and provides a live graph to visualize changes over time. You can customize alerts to notify you when charge drops below your chosen percentage or reaches full, helping you stay powered up without constant checking.

Setup and usage: Install and configure complications via the watch app on your watch or iPhone. Updates typically run every 12–60 minutes (WatchOS dependent); if automatic updates stop for more than 1.5 hours, tap the complication to restart. The latest update time is shown under the watch’s charge status in the iPhone app, and you can tap the complication to refresh manually. A circular complication can be assigned to show the outer ring and inner number for the phone and watch battery levels. The developer is Japanese, and the support site can be translated into multiple languages using the Translate option on the right side of the site.