Apple recently admitted that there is a software issue within iPhone 6s and 6s Plus models that is affecting a number of customers. Users who are traveling between time zones appear to be those most affected. The glitch seems to be adversely affecting the battery indicator, in that it fails to update the battery percentage after the time zone switches. The indicators inaccuracy is resulting in flat phones and frustrated apple customers, with users seen airing their annoyances over Apple support community pages.
Apple is working to fix the problem – in the meantime they suggest a quick (temporary) fix for those affected.
- Restart your iPhone
- Go to Settings > General > Date & Time > ensure that Set Automatically is turned ON.