Since the power bank is mainly designed for charging mobile phones, its charging current is
about 1A. When the mobile phone is fully charged, it enters a trickle charging state, and
the charging current will become very small.
At this time, some power banks will automatically shut off to save the power. The charging current of a smart device is relatively small, which may cause a mistaken detection by the power bank that the mobile phone is fully charged. Thus, it turns off the output and the smart device cannot be charged.