Mini3 non-CAN charger version uses the "PF3 Charger Mains AC Sense Input" pin to determine if the charger is connected. If PF3 input indicated that an AC charger is connected BMS checks if the battery needs charging (e.g. looking at the battery voltage level) then it closes the contactor between C+ and B+ terminals if charging is needed. During the balancing stage at the end of charging, the contactor may be closing and open according to the algorithm to balance the cells. After finishing the charging, the contactor is opened. Also, this contactor is opened whenever a protection event occurs. Note: the PF3 input pin has to be set up through the Control Panel on the GPI pin of your choice.