I think I'm on to something. I've had a 4s since the first day they came out, and I've had all kinds of heartache over this battery issue. I've read about 25% of the posts on this forum, so I've seen the patterns of complaints and the common fixes.
Back on page 343 of this forum, I spoke of a theory of a dual antenna issue on the iPhone 4s. While some agreed with some of my findings, the biggest argument against this was that the problems also happened on other iOS devices. So, I think I now have a revised theory, and I strongly believe in it based on patterns I've seen. The issue has something to do with how iOS 5 handles networking, both wifi and 3G. Whenever my phone is able to access the network, I can experience issues. But the ephiphany for me today was a pattern over the past 2 days of my usage, combined with other things I had been seeing and spoke of on page 343. I haven't charged my phone in 2 days. Yesterday, I attended meetings all day in a conference room in one building and lost 32% of my battery life over the course of the entire day, with light actual usage and mostly standby drain. My standby drain tends to be pretty decent after a few full cycle discharges and charge back up and following lots of tips that people have put forward like resetting networking settings, turning certain features off, etc. But, my phone still drains like crazy on phone calls and most usage of apps. Then, today, my meetings moved to a different building and different conference room where I had a much weaker cell signal. The signal is there, but just weak. After only 4 hours of meetings, i had lost a staggering 48% of battery life, and I never once used the device! This was all standby drain. Then, when I started using the device, I was experiencing the infamous 1% loss every 2 minutes situation.
What this tells me is that iOS 5 is somehow managing networking very inefficiently. People talk of many things that cause drain, but they are always related to network or GPS access in one way or another. I believe that if you don't have a 4 or 5 bar type of signal or very strong signal on wifi, you are at high risk to experience battery drain. And, since most of us don't experience these ideal conditions, we are at risk. The risk is obviously also related to your device's configuration. Devices configured in certain ways or that run certain apps are experiencing severe drain, and the problem apps or services are those that hit the network. This makes me really wonder... Do I have apps or notification services that I can't tell are running that are trying to go get updates from the network? I shutdown all my apps earlier today, I don't run push email, and I have most synching type things disabled, but I still saw the drain. Maybe it was notification center or some other app that was running in a background process but not visible in the running apps list. When apps try hard to get to the network, and they can't, the battery drains excessively fast. I notice this in active usage, but it would stand to reason in standby as well. Maybe iOS 5 also tries to work harder when trying to get an update from the network, whereas perhaps there were fewer tries being performed within a time interval or quicker attempt by the device to give up when the signal was less than ideal under iOS 4. Maybe iOS 5 tries to boost antenna signal more actively than iOS 4 did...
I don't have any solutions other than those already recommended, but I do have these observations, and I just wanted to share what I'm noticing as I experience it.
Phone: iPhone 4S 64GB
Provider: Sprint
Homebase: Raleigh, NC