Circuit/System Description

Before connecting the battery charger to the hybrid/EV battery pack, it is necessary to raise the voltage level of the battery charger output to match the hybrid/EV battery pack voltage. This is called the precharge of the battery charger. During precharge, the charging positive contactor is closed. Also the drive motor battery charger cable needs to be plugged into the hybrid/EV battery charger receptacle and utility power needs to be enabled to the vehicle. The hybrid/EV powertrain control module 2 monitors the amount of time it takes to achieve the proper pre-charge voltage.