Did you condition the battery when you first got it? I gave mine several cycles of full charge then full discharge and now I am getting better than stated battery life. Almost 5 hours using wireless. I use it during the day and it sometimes drops to 3 bars. Then I charge it at night. Back at work next week so I shall see how it goes then on the move and away from the charger.

One thing I have heard is with these sorts of batteries every so often it can help to let the battery get quite low rather than always having it near full charge. Not for the battery so much but rather so the power circuits in the device stay in calibration. No idea if that is true or not!