WE-DIG (Windows Embeded Developer Interest Group) was looking at power management this past month and had a few tibits of information that I need to add to my power management FAQ.  You can read more about WE-DIG’s finding at the Windows Embeded Blog.  They did some of their test using an AT&T Tilt (my current phone).  Changing the backlight settings on the Tilt had a huge difference on the devices battery life.  Depending on the settings the devices life ranged from 11 to 34 hours. They also mentioned that writing a file to a memory card uses 32 times the power of writing it to the built in memory.