What is meaning of Capacity of battery ?

1. The capacity of the battery is measured by unit ampere hour capacity.
2. Efficiency of battery is ratio between discharging and changing current.

Efficiency (ƞ) =

Ampere hour output
  Amper hour input

Charging of battery :-

Battery has to be charged with DC.

(i)     Charging voltage :-

Always heigher than voltage to overcome the initial resistance of the battery and the charging current to flow through the battery.

(ii)    Float charging :-

Charging a fully charged battery under no load at a rate equal to its self discharging rate. This enable the battery to remain at fully charged condition. Onboard float charging done for maintaining battery voltage.