Battery measurement issue

[malkavi]

I have started playing with the python bindings to make a bt-scale using xwiimote, but I have noticed that the battery measurement of my balance board is always 71 or 72%.
I have try with xwiishow and I have the same issue. The first test was with low battery, but the next one was with charged batteries.
I have try also with a wiimote, with 3 leds on of battery, wiishow show 29%, with 4 leds on, 38%.

Kernel: 3.11.10-21-desktop
Opensuse 13.1 64bit

Sorry for my English.

Here is my proyect based on your examples: (python)
https://github.com/malkavi/xwiibboard