Fóruns do Ubuntu sugere o seguinte:
gconftool --type int -s /apps/gnome-power-manager/backlight/idle_dim_time ***time***
gconftool --type int -s /apps/gnome-power-manager/timeout/sleep_display_battery ***time***
gconftool --type int -s /apps/gnome-power-manager/timeout/sleep_computer_battery ***time***