It is expected that new iOS update to version 5.0.2 will finally fix all the remaining iPhone battery problems.
The battery is designed for approximately 200 hours. Depending on network configuration and time can also go down rapidly. It is currently being feverishly worked to reduce consumption by Siri, GPS and telephone network. Some data are hardware redundant, ie, too many settings to access the hardware. The device runs energy, if the hardware it requires.
If all goes as planned the iPhone will last longer with 5.0.2. The stated goal is 40 hours standby with 10 hours of use. This is 2x longer than HTC Desire HD, HTC Sensation, Sony Ericsson Arc S or Samsung Galaxy S2. Depending on the network it can also move the numbers down. For example: Someone is sitting in the basement and has no 3G reception and the network has an attenuation of 50%, then the device will search for better network coverage and that works on battery power. Thus, say a user: “the update was great,” because he lives next to a converter, or “my battery life has shortened” because he lives in a poorly developed area or in this area with great variation in the net signal.
There will be also a major update in Spring 2012. to iOS 5.1 which will bring voice commands to Siri. More to come…