Hello, the 7000 mAh electric fan can blow for 8 hours when fully charged.
It usually depends on the battery capacity and the motor power of the small fan. Generally, the lithium battery voltage is 1.2V, the current is 800mA, and the power of the small fan. the motor is 2 W/hour, 1.2 x 0.8/2 = 0.48 hours, 0.48 x 60 min = 28.8 minutes.
Absolutely, the maximum output current of the USB interface is 500 mA, but generally it can only reach 350 mA. If it is a USB fan designed and manufactured by a professional manufacturer, its rated input power will not exceed 0.35A times 5V when using USB power supply, so it can be powered by a cell phone charger. However, please pay attention to whether the mobile phone charger interface is compatible with the fan. If the Fri sheettilator can be plugged into the charger, there should be no problem. Otherwise, you have to do the wiring yourself.