[rudra]

Thanks for the nice tip. Though I kinda knew about it already. Here is what I know,

calibration :
it is done when battery percentage sensing goes off with time.It is like setting up max and min voltage levels as 100% and 0% charge level and subdivide the range. Now i don't know how or if they account for the non-uniformity of energy-output/input of every percent charge level. May be they just dont go to all that complexity and linearly divide charge level scale according to voltage.

Battery charging :
these mobile batteries have a no of recharge cycles that they can take and function ok. so for longevity one should keep charge level between 40 to 65. That will afford you more cycles. the wider you go or closer you approach 0 to 100, the faster you expend your cycles.

also charging slower (less amp) and cooler will aford longer life too.
playing heavy games or doing things that engages near max resources means using higher amp, which means more battery heat. bad for its life.

I am very fastidious about what runs in my mobile.