Changes
/* Batteries */
* https://www.reddit.com/r/Multicopter/wiki/power
* C rating : the higher, the higher current you can draw http://www.rcheliwiki.com/C_rating
** C*Capacity in Ah=Current
** 20*2.2=44A
* S is the number of cells, and is representing the tension (1S=3.7V, 2S=7.4, 3S=11.1V, ...)
* Balancing: Cells need to be a the same charge level so we can avoid overcharging.
