One intrepid user thinks he might have found a fix. Oliver Haslam at iDownloadBlog reports that turning off the ability for iOS to automatically update its time zone may be the key to improving the battery life on the iPhone 4S.
Haslam reports that after turning off the "Setting Time Zone" toggle within the "System Services" section of "Location Services" (in the Settings app) has nearly doubled his phone's battery life and increased standby time nearly three-fold.
Haslam also surmises that the problem isn't actually with the iPhone 4S but with iOS 5. By turning off the automatic time zone functionality, Haslam saw improved battery life on various iOS 5 devices, including the iPhone 4 and iPhone 3GS.
The Potential Problem
Haslam thinks that a bug might have crept into iOS 5 that keeps the phone pinging various location servers to update its time zone. This constant pinging drains the battery.
I've seen location-based apps that aren't properly optimized suck battery life like a sieve. In fact, I initially blamed the new Radar feature in Foursquare for iPhone for my battery woes. Disabling that feature definitely improved performance on my device.
Other users have targeted iCloud and other sync services as the culprits responsible for declining iPhone 4S battery life. At Macworld, Christopher Breen detailed his own exhaustive efforts to try to track down the source of his phone's draining battery.
No Magic Cure
Although turning off the "Setting Time Zone" feature might work for some, it isn't a guaranteed solution. Your mileage, as they say, may vary.
It seems that there is a very real software problem affecting not just the iPhone 4S, but potentially other iOS 5 devices. We've reached out to Apple for official comment on the battery issue.
Has your battery life declined since upgrading to iOS 5? Let us know.