Apple Working with iPhone 4S Owners to Address Battery Life Issues
Since the release of the iPhone 4S, some users have been complaining about poor battery life. Even with Apple having quietly reduced the standby battery life from 300 hours on the iPhone 4 to 200 hours on the iPhone 4S, active-use battery life for the iPhone 4S was supposed to remain the same or better than on the iPhone 4. But some users are indeed seeing rapid battery drains, both while in active use and in standby, suggesting that some sort of background task is sapping the device's battery under certain circumstances, according to The Guardian.
One user in particular noted a battery drain of 10% per hour even in standby mode. The user was able to replicate the issue with all features such as Siri and location services turned off, and even on a relatively clean phone with no apps installed, hinting that the battery drain was coming from a core functionality on the device. The user does report, however, that Apple has reached out in an attempt to research the issue, asking to install system monitoring software on the device to help figure out what is going wrong.
"I then got a call from a senior [Apple] engineer who said he had read my post and was 'reaching out' to users for data and admitted this was an issue (and that they aren't close to finding a fix!) and asked lots of questions about my usage and then asked if he could install the file below and that he would call back the day after to retrieve the info. I extracted the file from my Mac after a sync and emailed it to him. He was incredibly helpful and apologetic in the typical Apple way!"
Apple has yet to offer an explanation for the battery life issue, but anecdotal reports suggest that corrupted contacts may be responsible. Some users have reported that a backup and restore through iTunes can help, but until Apple offers an official solution those affected by the issue may need to experiment with various solutions.