Battery Doubler is a very smart program developed to extend the battery life of your laptop. It utilizes many techniques to achieve that purpose, such as reducing screen brightness, lowering CD performance, and a few other methods. The developer claims that the program can make your battery last for 8 hours, but from my own experience, 132% of battery gain was the best result I could get on a new Windows Seven Asus laptop.
The program can help you fix a damaged battery (which reports false remaining time) using the recalibrate wizard. It also can make your battery charge faster, which is a great feature. The program offers three power saving plans that will let you choose between performance and autonomy. Once configured, you will be able to see how much battery time is gained by using the program and the amount of time remaining till your battery is empty.
The program works best in Microsoft Windows 98 and ME, because these operating system have poor power saving options. It also performs very well in XP and Vista , but its effect is somewhat poor in Windows Seven as the latter is already shipped with advanced power saving options.