Charging time for power bank battery?

The theoretical charge time of the Battery: the Battery power divided by the charger's output current. For example: to a power of 800mAh Battery, for example, the charger output current of 500mA then the charging time is equal to 800mAh / 500mA = 1.6 hours, when the charger shows the charge is completed, it is best to give the battery about half an hour Of the charge time.