If you’re running ubuntu or xubuntu then you can improve battery life by running the following script.
Read the tweaks carefully as they prompt you for a y/n answer since answering yes to all will render your usb sockets useless when on battery. You’ll get an icon in the tray that will allow setting of multiple performance modes, namely Conservative, On Demand, Powersave and Performance as well as a list of possible CPU frequencies.
To Install and Enable it…
cd && wget -O .laptop-mode.sh http://goo.gl/7SPJWP
chmod +x .laptop-mode.sh && ./.laptop-mode.sh
To Remove it..
cd && wget -O .laptop-mode-uninstall.sh http://goo.gl/IGVK8e
chmod +x .laptop-mode-uninstall.sh && ./.laptop-mode-uninstall.sh