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 contactors are closed, but the multi-function contactor is open. 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.