since nothing is different from hardware point of view, it must be some powersaving options with ubuntueee, which prevents saving battery life.

after some googleing I found an old (2005) post, which helped anyway.

sudo apt-get install cpufrequtils

cpufreq-info

I could see that now cpu is working at 800MHz (which is good, since the max is 1.6 GHz)

after enabling cpu throttling, the next task was to get the applet in the ubuntueee, gnome taskbar.

unfortunately by default, the ubuntuee taskbar is locked for adding new applets (simply there is no empty area where one can right click and select “add panel”).

the solution is to “move” on of the applets a bit to create some empty space, hence right click and adding a new applet is possible.

so, the new panel looks like this:

not only the cpus (one cpu, but due to hyperthreating it seems like two), but I also added the temperature applet to monitor the temp of the processor.

looks much better and now it is estimated to reach around 5 hrs…

the only question remains, why it does not come as default on the ubuntueee distro?