Info on iPhone 4S battery

In case anyone wants to do their own testing with their 4S battery consumption, here are some observations from my own experience.

• When I first got my phone, I plugged it in and set up my phone while it charged. I have Sprint as my carrier. I originally set it up to disable iCloud and disable Siri. Everything else was default (I set up my wireless and Gmail account). After the phone fully charged, this was my experience:
  • The battery drained REALLY fast -- as in after about one hour of playing around with it (turning on Siri and messing with it, downloading two apps). Most of the time, the iPhone was in what I believed was sleep mode (screen was black).
  • I went online and read up on the various tips on enhancing battery life and tried the following:
    • turning off my wireless carrier data network
    • disabling Siri (I thought perhaps the Raise to Speak option along with the fact that Siri needs the network might be the culprit)
    • changed the locations options to only enable it for the apps that I wanted it to use
    • disabled Push for my Gmail account and set it for 1-hour fetching
  • Battery life improved, but seemingly only minimally. I was still experiencing a battery drain from 100% to almost 30% with only about 2 hours of internet use.
• I suspected that perhaps something was still draining my battery. Fed up, I decided to power off my phone (holding down the power button). What I then noticed was the "flower" symbol (the same icon that you see when the phone is busy or accessing the network). Basically it was a black screen with that icon in the middle for a good minute or longer. Finally it shut down, and then I re-powered my phone. After I had done this, I tried changing my settings again to be very conservative with the battery. Then I proceeded to drain my phone's battery until it powered itself off (just kept repeating various Youtube videos). This morning, my phone seemed to behave more normally.
  • The battery was still around 97% after about 40 minutes of both Pandora and internet browsing and bugging Siri with a handful of silly questions. My data carrier network was enabled, but I was using my wireless connection for all of the above.
  • On my way to work, I no longer had my wireless connection. I unpaused Pandora in my car and relied on my Spring 3G network to continue playing music. I also asked Siri about the current weather. When I looked at my battery icon, I noticed that my battery was behaving abnormal again -- I quickly dropped to 91% in a span of just 5 minutes. I turned off Pandora (signed out completely) and disabled my data carrier network (to ensure that any network connections were stopped). When I got to work I turned it back on, though I also entered my work's wireless coverage so the data carrier network was no longer used (though it was now enabled).
  • My battery was behaving more normally. It's now 2:15pm and my battery is still at about 82% from continual use of Pandora and web browsing.

My own thoughts, including other observations:

1. When the data carrier network is enabled, the iPhone will automatically try to search for hotspots. After a while, the "Personal Hotspot (*)" changes to "Set Up Personal Hotspot" and the iPhone stops searching for hotspots. I know for sure I have not set up anything with Sprint for tethering or personal hotspots. I don't know why Apple insists on automatically checking -- they should change it to a user option that can be toggled between manual and auto mode. Sometimes I can get stuck on finding my (non-existent) hotspots, and I REALLY see a drain on the battery.
2. A battery calibration might help.
3. Powering off/on your phone might help. If there is something running in the background that is causing problems, you'll probably notice it as the shutdown process will take longer than normal.
4. In general, Sprint 3G causes a huge drain on the battery. Maybe it's just the fact that it's 3G -- I don't really have any reason to attribute it to Sprint, but that's my carrier, so I suppose they're partly to blame.
5. Battery problems is probably not directly related to Siri. When I use only a wireless connection, I don't see any drastic battery drains. However, on 3G it's pretty bad.
6. If you are experiencing high battery drain, the culprit could be that there is something continually accessing the network (whether wirelessly or through your phone carrier's data network). I have to wonder if iOS 5 forces the closure of a connection when it goes to sleep, or whether there is a mechanism to detect timeouts. At any rate, if in the end we have to disable alot of these "automatic" features (e.g. email push vs fetch) for the sake of battery life, then what's the point of having the iPhone?
7. Then again, we could just be looking at a crappy batch of batteries in the intial release of the 4S.