I dont use it but UL has a battery state bulit in along with the clock that comes default. It has options for icos so I am not sure how it works or even if it works but it is built in. Let us know how it works if you get it working. I use the SPB PP battery status that is across the top of my screen.
BatteryStatus also has lots of different system state items available like memory, battery (imagine that
), voltage, cpu % etc... Its a great plugin and barely sips memory.