Windows 7 BatteryBar is a free, good looking and customizable tool which lets you see your laptop’s current battery status.
To customize the settings click on the the Battery icon in the system tray. You can change the taskbar color to Red, Green, Yellow & Auto. If you change the color to Auto then it will change the color according to the remaining battery percentage:
100% – 50% = Green
49% – 11% = Yellow
10% – 0% = Red