Ok, I have been up and running with no charger for 13h 41M on the extended battery on what I would call heavy use. I have 15% left - it's the first time it's gotten this low ever. 30 Min Voice Calls. At least 20 IM's Chat application running all day and being used. 4 hours 16M display on. Phone Idle 9H 24m Wifi on all day. Cell Standby all day time without signal 31%. I probably played about 3 1/2 hours of games that use graphics and internet. What do you think?