Few days ago, i did try to start the battery monitor, but at the end, i couldn't find any program on the default KDE installation that would give me a battery monitor, so i think i have to install another packages, but then today i know why did the battery monitor won't start. It's because the ac modules wasn't loaded, so it won't run. So if you are looking for programs to look at your battery status and you are running KDE, just run KDE Control Center and look for Laptop Battery and click the Start Battery Monitor. You will get a new icon on the systray (look at the screenshots below). If you don't see that icon, please check the kernel modules by using lsmod. Make sure that all ACPI modules has been loaded. In my case, i'm loading ac, battery, button, container, fan, processor, thermal, and video, but in order to have the battery monitor, i think you will only need to load the ac and battery modules only.