My TB47 was completly dead it wouldnt charge or come on at all.
This is whati tried, I opened the battery disconnected the board from the battery. I cheked the voltage and it would indicate 0.6 volts.
There is a thick red cable(+) pole ,
and there are two thick black wires one connects to the Charger to the Board with the LEDs
on Top and the Other on connects that same board with the LEDS to the Cells.
I Jumped those two Black wires by temporarily welding another thick wire from the end of the black cable from the that bring the (-) pole from the Charger to the (-) pole that goes in to the cells
This way I Bypassed the board and feeding 26 volts in to the cells.
I did this intermittently checking the voltage on the cells about every 3 minutes, making sure the battery didn’t overheat.
The voltage at the beginning was 0 volts then it started climbing to about 5-6 volts then 10-12 volts, then 15-20volts, and finally to about 23 volts. I let the battery cool down for about 15 min in between every 3 min charge, the charger and battery would get warm.
Once the cell had charge I reconnected the upper board to the cells, and I pressed the on button on the Flight battery and it went on the started charging by it self and working normally. the charge on the battery only went up to 3/4 full indicated by the lights.
Have not had a chance to test flight with the battery or a change to update the firmware on the battery.