I've had the phone since Tuesday and am wondering what other users are experiencing with the battery life and heavy usage? I have friends with the SGS and they told me that the battery is good after a week or so. I've read that the battery requires 3 full charge / discharge cycles to get the best out of it. With light use the battery seems fine, but playing any game seems to make the cpu rather hot and the battery quickly drained. Other niggles . . . I had a folder in the Apps that I put the games in. Once the phone is switched off the contents of the folder changes. Fortunately if you copy the folder onto the home screen then the contents remain, just not if in Apps. Possible signs of sluggishness after a few hours of gaming thus the CPU/GPU is hot. Some games (infrequently) have seemed to crash to home screen, yet run fine afterwards. Recharge rate is slow (was used to the iPhone). To answer the original question with specifics e.g. If using Navigation how long would the battery last? What would the discharge rate be as a percentage per hour? or Before gaming Battery = ##% Gaming duration = ###minutes After gaming Battery = ##% I'll run my own tests and update in due time.