Battery State of Charge

WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

The battery monitoring sensor system monitors the battery current flow and voltage to determine the battery state of charge. During the drive cycle the battery monitoring sensor system software monitors the charge and discharge current and increases the state of charge during charging, and decreasing it during discharge. During rest periods (key off with no electrical loads) when the vehicle enters sleep mode, the battery voltage is sampled to calibrate the state of charge. The sensor automatically executes this calibration anytime the vehicle enters sleep mode and when the total vehicle current draw is below 400mA. It takes 4 to 6 hours in the sleep mode to calibrate the battery state of charge to high accuracy. If the system draw does not allow the battery state of charge calibration over the previous 7 to 10 days the state of charge quality factor changes to flag this and some battery monitoring sensor system functions, which rely on the accuracy of the battery state of charge, may be temporarily turned off until a calibration takes place.

NOTE: Any devices left attached to the power socket that draw in excess of 200mA (or less depending on other battery loads), prevents a battery monitoring sensor from calibrating the battery state of charge.