Di con esto de casulidad:
$ sudo apt-get install acpitool
...
$ acpitool -B
Battery #1 : present
Remaining capacity : 1248 mAh, 17.11%
Design capacity : 7650 mAh
Last full capacity : 7296 mAh, 95.37% of design capacity
Capacity loss : 4.627%
Present rate : unknown
Charging state : charging
Battery type : rechargeable, LION
Model number : Primary
Serial number :
La batería de este portátil con casi 4 meses de vida ha perdido el 4.6%
de su capacidad =,(