The charging process is divided into the following three processes: trickle mode, constant current mode, constant voltage mode. When the battery voltage is lower than 3V, the charging module is in trickle mode and the charging current is 300mA. When the battery voltage is greater than 3V, the charging module enters the constant current mode and charges at full speed according to the set target current, with the power of about 21W. When the battery voltage rises to the target charging voltage (such as 4.2V), the charging module enters the constant voltage mode, and the current gradually decreases while the terminal voltage of the battery remains unchanged. When the charging current decreases to the charging cutoff current, the charging ends. If the battery voltage drops to 0.1V lower than the target charge, the battery automatically starts charging again. (Note: If the voltage exceeds 4.2V, it is normal and will not damage the battery. If the voltage is 4.2V, the lamp still flashes, which means it is not full yet. Full charge is not just to see the charging voltage.)