Solar Voc Working principle diagram

DETAIL
maximum chargeable voltage when connected in series = 4.2 X N
                                                                                                       Normal voltage can be set = 3.7 X N
                                                                      Once the battery voltage drops, it will discharge the full current
                                                                                                       battery full charge stop set=4.2X N -0.1Vtg
                 controller can synchronize the battery voltage when the voltage is regulated and directly charged.