Just under a week ago, my iphone’s battery life took a nose dive!. It would be out of power in 3 to 5 hours instead of keeping over 80 at the end of the day. My first thought was I had some rouge apps running in the background. I turned off backgrounder.. Still dying. Killed GPS and removed the AT&T turn by turn directions app I just installed, nope, Killed 3G, killed WIFI, still dying. I was not sure what else to try, so I turned all my email updates off just to get through the day. THAT was it. Seems that something odd was going on with work email account which is connect via microsoft exchange server. The fix was simple enough, I went into setting and changed my work email from “Push” to “Fetch”. (you can find this under the advance tab of ‘Push’.) I have yet to change it back, but i will at some point just to test, but my battery life came right back to normal performance after I made the change.
So if your battery life suddenly goes south on you, try turning off email, or at least set everything to fetch. Could be the easy fix.