I'm going on 72hrs and battery is still at 50%. I have no SIM installed, and running on WiFi the whole time, with weather/email/facebook updating. My 900 got wet and the screen is dark, but is still functional/visible if external light shines on it. I normally can go 24-36hrs of normal use in a full signal 3G area. Not much difference in 2G/2.5G mode.