The Battery Capacity is a measure of the charge stored by the battery. It represents the maximum amount of energy that the battery can deliver under certain specified conditions.
The actual battery capacity can differ significantly from the battery capacity mentioned on the battery because the battery capacity depends on factors like the age and history of the battery and the temperature.
Battery capacity is measured either in watt-hours (Wh), kilowatt-hours (kWh) or, most commonly, in ampere-hours (Ah) which indicates the number of hours for which a battery can provide a current equal to the discharge rate when the battery is operating at its nominal voltage.
Charge and discharge rates affect the rated battery capacity. If the battery is discharged quickly using a high current, then the actual battery capacity will be lower than the rated battery capacity.
Final Statement: The battery capacity of a battery measures the amount of charge stored by the battery and is representative of the maximum amount of energy that the battery can deliver under specified conditions.