According apple.com: Up to 10 hours of surfing the web on Wi-Fi, watching video, or listening to music Up to 9 hours of surfing the web using 3G data network I'm using my iPad2 for some time and I think my battery drains a bit faster. So I'm just wondering what that 9-10hrs really mean. What if my iPad goes to sleep mode with tens of applications opened and no active data connection? What if my iPad goes to sleep mode with imo.im or other network using app opened? Does the time in sleep with active data connection counts towards 9-10hrs? How could I be sure that my iPad really last 9-10hrs? Just open one browser tab and surf the web non stop without opening any other application and without turning off to sleep? Thanks!