The iPhone 4s ( and the iOS 5 ) has attracted a lot of criticism for being a power hog. I am actually worried about this problem because I don't want to end up with a dead phone during my day. To remedy the situation - I did a four day experiment to determine what settings I can use that will allow me to maximize my use of the phone - with the least number of charge in a day. BTW - as a disclaimer - in case I do end up with a dead phone midday - I have a portable backup power source.
All features turned on all the time. This means that I had push e-mail on. I also had the Cellular Data network turned on. Wifi is on and I also had it checking for available WiFi networks.
I switched off WiFi. Cellular network is turned on. I switched off push Mail. App notifications are still turned on.
I think I reached the sweet spot on the third day. I switched off cellular data network (but switch it on occasionally when I need to surf and there are no WiFi connections available), I switched on WiFi - but I switched off the option to check available networks. Push e-mail was turned off. I also kept running apps to a minimum - especially those which tend to fetch data online ( for example - Twitter ).
I switched on Push e-mail - but kept Cellular network turned off ( on when I need it ). I continued to keep running apps to a minimum. WiFi is always on but checking on available networks is Off.
From my experiment - it seems like the maximum hours of usage for the phone is six hours. This is pretty much aligned with what Apple advertises. My phone usage is mostly for online surfing. I rarely use it for calling ( since most phone calls are for work - and I have a company issued phone for that ), I also rarely text. Music is around one hour a day and I rarely watch videos on the iPhone.
This just means that I can use the phone every day and have it charged while I am sleeping.
Do any of you have different settings that seem to have maximized the battery life per charge of your iPhone?