This video will help you to know full details about the power bank. It also shows the major difference between the advertised and actual power capacity in the power banks. Power bank manufacturers marketing strategies are also shown here. Steps to find actual capacity of power bank: 1. USB output capacity = Advertised capacity * 3.7 / 5 2. Actual capacity = USB output capacity * 0.9 3. N = Actual capacity / Battery capacity Watch the youtube video here: https://youtu.be/qjV_dR6XFaI I m available @arun28murugan