BATTERY DRAIN

Check Settings > General > Usage > Battery Usage to see what app(s) are using the most power.

OK. I recommend you take my suggestion anyway. "Basically idle" does not necessarily equate to "idle."

HI. Try to follow the instructions on this page in order to maximise your battery life: https://www.apple.com/batteries/maximizing-performance/

http://www.idigitaltimes.com/ios-82-battery-life-problems-how-fix-quick-drain-is sues-iphone-ipad-and-ipod-422229

Try to reset your device. This won't delete your data stored on the phone.

• Press and hold the Sleep/Wake button
• Press and hold on the Home button
• Keep holding both buttons until the display turns off and back on with Apple logo on it.

You may also try to reset all settings: go to Settings - General - Reset - Reset All Settings

You may also try to follow these steps:

1. Navigate to settings/general/ battery usage. Check the applications. This will show you which app eats up your battery.

2. Turn off iCloud keychain: Navigate to Settings/ iCloud/Keychain / turn it off.

3. Limit apps activity on the background: Navigate to Settings/ general/ Background App refresh/ turn it off for each application which uses to much power.

4. Disable auto brightness: Navigate to settings/ display and brightness/ auto-brightness. Turn this option off.

Thanks for this. I too am having issues on a 14 mos. old iPhone 5s.

Twice in the last week, I left my home to go to the office and the battery was at 97%/100%.

20 minutes later it at 0%, and the phone shut off. Just plain dead.

I have turned everything off, did resets, etc.

You may have a bad battery. Take it to an Apple store and they can test it.