I had this problem already twice. I charged the 3 batteries yesterday. Today I want to do a flight but after connecting to Tello wifi and than launching the Tello app it shows that the battery is empty on all 3 batteries.
It is the same on TelloFPV. The strange thing is, when I plug them back in the charger hub they are charged in couple of minutes what means they were not empty at all though in the apps the battery icon shows red. It drives me crazy.