It looks like iOS7 drains the battery too quick on my 4S. Less than a half day almost without talking and I'm on 19%! I hope it will not be like this. How about you guys with 4S?
Disable background app refresh.
Yes sure it's not new battery I understand, it's an older phone, I've got it when they just came out, but that doesn't change the fact that it was pretty good (even if not like new) on iOS6 and its really bad on iOS7...Ars Technica did a great review of iOS7 and all devices suffered from decreased battery life, but the iPhone 5 was the worst, with the 4 and 4s fairing the best. Is it possible your battery is old and/or has been charged/discharged enough times that even if it says it's at 100%, it's actually only holding say 80% of what it could when new?
Disable background app refresh.
It's sad when you upgrade to a new iOS to use all the cool and great new features, only to have to disable them just to let your phone do what it did before.
Try resetting network settings, and if that doesn't work, try resetting the phone and setting it up as new. There's clearly something not right.
Or alternatively, wait to see if Apple releases any updates. Rumor has it that they will be releasing one soon.
Left my newly upgraded 4S at 100% before went to bed, and woke up to a completely drained/dead phone. needless to say - missed all my alarms!! Thank you IOS7![]()