Battery Monitoring Sensor

The BMS  will go into deep sleep and will awake periodically to obtain battery information.

When the ignition is switched OFF, the BMS  records the startup battery SOC  and monitors the startup battery condition.

If the startup battery SOC  falls by 8% from the critical start point, the BMS  will start to monitor the startup battery for 5 minutes. It also sends a 'Warning' message on the LIN  to the BCM  /GWM.  If the startup battery charge has continued to fall below 50% due to the high quiescent drain current after the 5 minute monitoring period, the BMS  will determine that the control modules are still 'awake'. The BMS  sends a 'Shutdown' message on the LIN  to the BCM  /GWM.  The BCM  /GWM  then transmits a 'Shutdown' message on HS CAN  buses to all control modules, requesting them to shutdown.

When the vehicle is in Power Mode 0 (vehicle locked and armed), the BMS  monitors the startup battery SOC  for a further 15 minutes. The BMS  determines when the startup battery SOC  is still dropping due to the quiescent drain current. The BMS  sends a power disconnect signal to the BCM  /GWM  on the LIN.  The BCM  /GWM  then sends a signal to the PJB on the hardwired connections to open its internal relays. When the PJB relays are open, the power supply from the startup battery to non-critical control modules is removed. The non-critical control modules are any modules associated with the infotainment system and also the climate control system.

The use of the CAN  bus communication makes sure that no other control modules 'wake' during this process. When CAN  systems bus communication was used, all modules on the CAN  systems bus would be woken by the message.