The time of different types of power bank charge and discharge is different，it depends on power bank’s Current, voltage and charge environment. As in Mainland China,the current is 220V，but in taiwan it come be 110V. the 4000mah 5V/1A power bank need 8-12 hours to charer over when in mainland China.（the circuit design with circuit protection will make charging time be long），charging for IPHONE 5 could be 4000*3.7*0.9/5/1470=1.8 times