iPhone 5 Battery Replacement Program
Apple has determined that a very small percentage of iPhone 5 devices may suddenly experience shorter battery life or need to be charged more frequently. The affected iPhone 5 devices were sold between September 2012 and January 2013 and fall within a limited serial number range.
You can check the link below if you are eligible to change your iPhone battery.
*You need the iPhone serial number to check.
How to get your iPhone serial number
1. Go to settings
2. Go to General
3. Select About
4. Find Serial Number under Model