Some styles of protection boards need to be charged and activated to have output after discharge protection. Your charger may have the function of detecting voltage, and it will not charge if the output is not detected. If the charger has the function of detecting voltage, it is best not to use over-discharge protection.
The principle of the protection board is that as long as one section reaches (polymer 4.18V, iron-lithium 3.6V), this section starts to discharge. Keep charging, and then the highest section reaches (polymer 4.25V, iron-lithium 3.75V), it will protect all and cannot be charged. The battery packs connected in series are charged and discharged at the same time. This is your battery consistency problem, and the protection board is working normally. The protection board, as the name implies, "is protection", the protection board is to protect the battery, the balance function has some, but the balance ability is limited, if your battery pack is not well matched according to the wiring instructions, just charge and discharge the protection board a few times. To achieve a very ideal balancing effect, balancing is mainly to prolong the battery life and make the consistency of the battery better. However, the consistency of the battery cannot be determined by the balancing function, but depends on the battery difference of the PACK.
Use a multimeter to measure the battery voltage of each string to see if the battery voltage is full at this time, which leads to the overcharge protection of the protection board.
