Sorry for the bump, however, I have found this software:
http://www.nistech.com/BatteryBar/Default.aspx
quote:
Originally posted by http://www.nistech.com/BatteryBar/Default.aspx
With Battery Bar you won't ever have to guess how long your laptop's battery will last. Battery Bar always shows you exactly how much time your laptop's battery will run. Battery Bar uses the most accurate time prediction algorithm on the market today. It also displays the current percentage of battery power left. Battery Bar is intelligent, the more you use Battery Bar the more accurate it gets. Battery Bar continuously displays status icons so that you can always tell if your battery is on AC, charging, battery power, or if your battery is low. Battery Bar will also let you specify a battery percentage level that when reached Battery Bar will shut down the computer. Battery Bar has the ability to run on top of all other programs so that it is always visible. Battery Bar is small so that you have plenty of screen space for other programs.
I haven't tried it, but you might wanna try it
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