The difference between the split port and the same port: The standard charging current of the split port is 8A, and the positive and negative pole of charging and discharging must be separated; the charging current of the same port is the same as the discharge current, and charging and discharging are at the same positive and negative level. Without compensation and with compensation: The compensation is to discharge the high voltage cells when charging with resistors and wait for the low voltage cells to charge the voltage to achieve the consistency of each voltage and improve the performance of the entire battery. Before installing the protective board, the batteries must be well matched (the voltage difference of each battery is no more than 0.05 V, the internal resistance difference is no more than 5 m2 and m2. the capacity difference is less than 30mAh). The performance of the protective board is better. The batteries are switched in parallel and then in series and make sure the welding is correct (18650 batteries are spot-welded with nickel plates and other batteries are welded with solder. Do not use screws, as it is easy to burn out the IC of the protective board.