It depends on your battery capacity. Normally, it takes 8-10 hours. This is actually not possible, depends on your battery, battery is not the nominal capacity? Can your battery be fully charged to 12000mA without nominal capacity? So the common situation is that the normal battery can be full for about 6 hours, if it is not normal, it is too possible.
In addition to the charging power, the charging time is also related to the battery capacity, if the battery capacity is 10wh, then, with 10w fast charge can be filled within an hour.