US Patent 10218204 Charging system on constant current mode and method thereof

A charging method on constant current mode includes communicating with a rechargeable battery by a central control module to obtain a first current and a first voltage required to charge the rechargeable battery; receiving a first current output instruction and a first voltage output instruction by first and second charging modules; outputting a second voltage and a second current to the rechargeable battery and transmitting an output value of the second voltage and an output value of the second current to the central control module by the first charging module; and when the central control module detects that difference between the output value of the second voltage and the first voltage is smaller than a predetermined voltage value, transmitting a fourth current output instruction, in which a fourth current equals the first current minus a predetermined current value, to the first charging module by the central control module.