A. Why does the battery can’t it be charged or discharged after installation?

Please check whether all the wires are connected correctly or not . whether the battery connection and connection with the charger are normal or not; whether the voltage of each string of batteries are within the range of the wiring instructions, whether the NTC on the BMS is plugged in ( If the NTC is not plugged in, the battery cannot be charged and discharged); check if there is Lock letter on the fist page of the APP which has disabled the charge and discharge ?

B. Why does the balance function can not turn on ?

Please check whether you set static balance or charge balance.
Charge balance: Only when there is a charging current, Cell voltage has got to balance start voltage,and voltage difference with highest and lowest has reached its set voltage difference vlue, the balance will be turned on when these two condition matched ;
static balance: when there is no charging current, Cell voltage has got to balance start voltage,and voltage difference with highest and lowest has reached its set voltage difference vlue, the balance will be turned on when these two condition matched ;

C. Why does the protection board only balances the battery on one side?

The BMS is to turn on the balance either even or odd numbers at one time, and the balance of odd and even batteries will not be turned on at the same time, which is to reduce heat generation

D.Why does some series cell with very low voltage and some series cell with high voltage ?
Some buyers did not connect the B- port to the battery negative port with bold and short wire ,the first and second series cell will have very low voltage 0.? V
when there is one series cell without voltage , and its neighboring series cell has high voltage , when you meet this problems . it maybe some lossen connection with wires and battery , please fix connection well,or Maybe the correspondent balance section was damaged .