Early adopters of the new iPhone 4S from Apple have noticed a unusual battery drain issue. After many users reports on various forums, 9to5Mac has determined that the issue may be related to the location services feature in iOS 5. The specific function is the “setting time zone” function in location services which polls your current location in an attempt to adjust your time zone. To change this setting simply launch the Settings App and proceed to Location Services > System Services and then change the “Setting Time Zone” setting to off. From the Apple forums:
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.
The iPhone may not change your time zone for you as you travel but this can be remedied by simply turning this feature back on when needed then back of when not. This is not a final solution but a temporary one until Apple finds and distributes a fix for the current flaw.
The iPhone 4S is rated at 200 hours of standby which is 100 lower than the iPhone 4 despite having a slightly more powerful battery. Apple recommends that iPhone owners allow the phone to complete 1 full battery cycle a month to improve battery life. This process involves charging the phone fully and letting it drain completely. After completing these steps posted above, post below if it corrects your issue we would be happy to know.