1. Usually there is internal resistance in all mobile phones and USB cables. As a result，the power bank will lose power when you charge your mobile phones. we called it is Conversion Rate

2. Normally it takes about 6 to 7 hours to charge the power bank full，but if you play your phone at the same time，it will take more.

3. The output power is different among mobile phones because the internal resistance is different.

4. All the power banks have Conversion Rate，when you charge your phone，there will be twice energy conversion!