Apple Admits iOS 5.0.1 did Not Fix All Battery Issues
 

The just-released iOS 5.0.1 from Apple that was supposed to fix the poor battery performance on the iPhone 4S does, and does not. The fix did just that in many iPhones, but left many out in the cold with the same problem. Apple said it will be continue to investigate the problems. The recent round of complaints suggests, however, that not all iPhone 4S owners are having software-related problems. Some of the more serious cases — particularly those that haven't been improved by the iOS 5.0.1. update — could stem from hardware issues

http://www.hardocp.com/news/2011/11/...attery_issues/