There is a flaw in the new iOS 5 software, which causes a rapid battery drain for the Apple Inc. (NASDAQ:AAPL) iPhone 4 and the iPhone 4S. Many people found that the “Setting Time Zone” service in the Location Services settings seems to keep operating even when there is no chance that the phone user moved to a different location.
There is an icon besides the setting that indicates whether the location has been detected in the past 24 hours. Location services use a combination of WiFi network, mobile mast data, and GPS sensor input to calculate the position of the phone. If this calculation is made too often, then it will start to use the battery power unnecessarily.
“It appears that iOS 5?s GM release introduced a bug that causes the Setting Time Zone function to keep the location tracking circuitry running constantly, draining battery power considerably. Switching it off may mean that your iPhone will no longer set its own time zone when you travel, but that’s a small price to pay for having your iPhone last more than 12 hours on a full charge? We have tested this method on 4 different iPhone 4s handsets, including an iPhone 4 and an iPhone 3GS. All have reported drastically improved battery life after switching ‘Setting Time Zone’ off,” wrote Oliver Haslam on the iDownloadblog.
To find the Setting Time Zone feature, go to Settings -> Location Services -> System Services -> Setting Time Zone. Hopefully Apple fixes this in an iOS 5 update in the future because turning off the Setting Time Zone feature does not seem like a good fix. I depend heavily on this feature on the iPhone when traveling.