Mobile phone charging bank generally have an indicator light, if it is a row of lights, this row of lights also take into account the power display, the more lights on, the more power, when charging these lights will flicker.
There are also charging treasure is digital display, connected to the power supply charging digital display screen will light up, showing the remaining power and charging sign.
If there is no reaction when plugged in and the light is not on, it indicates that the charging bank has not been powered on, which may be a fault, and it is recommended to repair.