Adjust Backlight Brightness When On Battery Power (Ubuntu)

For those of you running Gnome, this will help you tweak your power management settings.

Ubuntu provides a nice little power management utility in System + Preferences + Power Management, and it includes a checkbox to tell it to dim your backlight when on battery power to save your battery time. By default, it will drop your backlight by 50% from your regular setting. I find that my backlight is bright enough that I can run as low as 30% brightness on battery and be happy, but I like full backlight strength when I'm running on AC power.

There's a quick and easy tweak you can do to change how far to drop the backlight when you're running on battery power. To do this, open Applications + System Tools + Configuration Editor. Be advised that you can do serious damage to your system setup in here, so be careful to only change what you understand.

Once you're in the Gnome configuration editor, browse down to:
/apps/gnome-power-manager/backlight
and look for "brightness_dim_battery".

This setting is the percentage to dim FROM whatever it's at before you lost AC power. In other words, if you normally run 100% and want to run at 30% when on battery, enter 70 here.

So, set that on-battery brightness as low as you can stand and you're on your way to a longer lasting laptop battery.