Battery Monitoring System Control Module Self Calibration

WARNING: This page is about a different car, the 2020 Jaguar XE and 2019 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.

The Battery Monitoring System (BMS) control module periodically initiates a self-calibration routine. To self calibrate, the BMS first charges the startup battery to its full condition.

NOTE: If the vehicle is only driven for short periods the charging process could take a number of days to complete.

When the startup battery is fully charged, the BMS control module will discharge the startup battery to approximately 75% of its full state of charge. The BMS control module never discharges the startup battery lower than 12.2V. The time taken to complete this part of the routine is dependent on the electrical load on the vehicle.

When the second part of the routine has been successfully completed, the BMS control module will return the startup battery to its optimum level of charge. The optimum level of charge will be between 12.6V and 15V, depending on startup battery condition, temperature and loading.

The BMS control module also monitors the startup battery condition with the engine switched off. If a low voltage condition is detected, the BMS control module can request the infotainment system is switched off to protect startup battery voltage.