Bms hard reboot function

A battery system for a vehicle, comprising:

• a first battery having a first voltage;
• a positive contactor electrically connecting a positive terminal of the first battery to a positive high voltage bus;
• a negative contactor electrically connecting a negative terminal of the first battery to a negative high voltage bus;
• a first switch for turning the vehicle ON and OFF;
• a second battery having a second voltage that is lower than the first voltage;
• a battery management system controlling the positive contactor and the negative contactor, the battery management system powered by the second battery when the first switch turns the vehicle ON;
• a backup power supply for powering the battery management system when the first switch turns the vehicle OFF;
• a controller configured to selectively supply power to the battery management system from the backup power supply when the first switch turns the vehicle OFF;
• a second switch for disconnecting the backup power from the battery management system;
• and
• a service tool interface configured to interact with a service tool to operate the second switch.