It seems my battery is still charging normal after I swap the red&black battery wires in the JST plug.
After leaving the quad off with USB cable plugged in for all night, the battery voltage is measured at 4.3v 
(with a Fluke 179 - should be max at 4.2 only)
However, even with this voltage, the quad still reports that my battery is empty (red empty battery symbol).
Even after all night, the red light is still on.
Anyone has any idea how to fix this, please?
Thanks very much
-Thanh