Charging System - System Operation and Component Description — 2016 workshop reference 4027

Battery State of Charge

The BCM uses the battery current sensor to keep track of the battery state of charge. The battery current sensor is a Hall-effect sensor attached to the battery ground cable. During a drive cycle the Electrical Energy Management software adjusts the battery state of charge by monitoring the charge and discharge current and adjusting the state of charge up during charging, and down 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 BCM automatically executes this calibration anytime the vehicle enters sleep mode and when the total vehicle current draw is below 300mA. It takes 8 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 Electrical Energy Management Functions which rely on the accuracy of the battery state of charge may be temporarily turned off until a calibration takes place.

Engine Off Load Shed

When the engine is off, and the BCM determines the battery state of charge is below 40% or 10% of the charge has been drained or 45 minutes have elapsed, a load shed message is sent over the CAN. This message turns off the audio/navigation system to save the remaining battery charge. Under this condition, the FDIM displays SYS OFF TO SAVE BATT (without navigation) or BATTERY SAVER — SYSTEM OFF PLEASE START THE ENGINE (with navigation) to notify the driver that battery protection actions are active.

Engine off load shed occurs when the engine is not running, and the ignition is in the ACC or RUN position. To clear the load shed state, restart the engine.

NOTE: To maintain correct operation of the load shed system, any electrical devices or equipment must be grounded to the engine or chassis ground and not the negative battery terminal. A connection to the negative battery terminal may cause an inaccurate measurement of the battery state of charge and may cause incorrect load shed system operation.

When the ignition is in the RUN position and load shed occurs, the IPC message center displays either TURN POWER OFF TO SAVE BATT (base message center) or TURN POWER OFF TO SAVE BATTERY (optional message center). The audio/navigation system will shut down after the message center displays it's warning.

If a fault occurs with the battery current sensor or circuit(s), the only engine off load shed strategy is a 45 minute timer. After 45 minutes have elapsed, the audio/navigation system turns off. To clear the load shed state, restart the engine.

Engine Running Load Shed

When the BCM and/or PSCM voltage is low, with the engine running, a message is sent by the BCM to either minimize or shut down the climate controlled seats, rear defrost, heated mirrors and DATC blower motor to improve system voltage. Under this condition, the IPC message center displays either LOW BATTERY LESS FEATURES (base message center) or LOW BATTERY FEATURES TEMPORARILY TURNED OFF (optional message center) to notify the driver that battery protection actions are active.

For more information on message center messages, Refer to the Owner's Literature or Refer to: Message Center - System Operation and Component Description (413-01 Instrumentation, Message Center and Warning Chimes, Description and Operation).

There are 3 states of engine running load shed:

Load Shed Entry Conditions Impact to Features Clear Conditions State Load shed If vehicle speed is below 16 These loads are incrementally reduced (if Voltage to the 1 equipped): Heated steering wheel and BCM is greater km/h (10 mph) , and voltage to climate controlled seats. These loads are than 12.7 volts or the PSCM is less than 11.5 volts turned off (if equipped): smart trailer tow the generator field or the PSCM measures current battery charge, heated mirrors, heated duty cycle is less draw greater than 0 amps. If backglass, and heated windshield. than 88%. vehicle speed is above 16 kp/h

Original table alignment retained · Scroll horizontally if needed

(10 mph) , and the voltage to the

Source reference 4027

2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.