Some iPhone 4S owners continue to experience worse battery life than they expected, even after the iOS 5.0.1 update. Not all devices are affected, but there are enough reports that Apple acknowledged there might be a problem.
The next version of iOS, 5.1, is currently in the testing phase for developers, and many expected to see a fix that improved battery life. Posts at RedmondPie and App Advice suggest that the expected battery life fixes are not apparent in the beta, but it should be noted that 5.1 is a work in progress and any assessment of its features (or lack) is preliminary.
Ars Technica talked to several analysts who pin the poor performance on new features like iCloud, Siri, new notification screen banners or location awareness. These features consume more data and may require extra juice from the battery. Suggestions for improving power performance usually focus on turning off certain iPhone 4S features like time zone auto-switching, Siri raise-to-talk or iCloud email push, but nothing has been shown to serve as a 'magic bullet' for all problem iPhones.
Michael Morgan of ABI Research put it this way: "Any undefined glitch is a massive problem to solve for such a complex system. iOS 5.0.1 supposedly fixed the problem for some users, but made it worse for others." Morgan believes it is a software problem. He has tested the iPhone 4 and the 4S and found the baseline power consumption of the 4S hardware is about the same as the iPhone 4.
If, as assumed, software is at the heart of this issue, it may take some time for Apple to locate the problem and issue a fix that works for everyone -- but that's better than a true hardware flaw, which would require a field repair or a recall to correct the issue.
[hat tip CNET]