The length of charging time mainly depends on the capacity of charging treasure and the charging voltage/current supported by charging treasure, as well as the voltage/current supported by the power adapter for charging treasure. It's not surprising how long it takes to charge the charger with a voltage/current. Some 20000mA chargers may take more than a dozen hours to fill up. If your Charge Po supports high current charging, you can buy a power adapter that supports the corresponding high current. The common high current input is 5V/2.1A.