What is the minimum charging current?

The NB Air's minimum charging current is 50mA. If the device reduces the current below this threshold, the NB Air will assume there is no load and stop charging.

Comparison: 

The minimum charging current for NB10000/20000 G3 is 60mA.

The minimum charging current for NB10000 G2 (Low current mode) is 80maA.