Hi, I got an iPhone ten days ago. The battery life was normal for the first 3 days or so. Then one day, I went to work with 3/4 full battery, put the iPhone to sleep while at work, and when I brought it back to life, I had the low battery life icon... Wifi was disabled, and I had not used it ONCE at work. What gives?? Today, the same thing happened only I went to work with a FULL charge, and 4 hours into my shift, the battery wad dead. Any suggestions?