Hello, I have a 15" Unibody MBP, 2.53GHz, 4GB Ram My battery rarely lasts longer than 2 hours. When I'm teaching, I am connected to a digital projector, I have the screen brightness at the lowest setting and I am using the integrated 9400 video card. Bluetooth is off and I am connected to the Internet via WiFi. My fully charged battery will only give me 2 hours of use in this situation. Does this sound "normal" from your experience? Battery Info 161 Cycles 96% Health Thanks.