2020 GT500 Battery Charging, Jumping and Replacement

[Snoopy49]

From The 2020 Mustang Service Manual

Battery Charging
When charging the vehicle battery by connecting the charger to engine or chassis ground, the negative charger clamp must be connected to an unpainted chassis surface or a solid engine component such as a generator mount or engine lifting eye. In this instance, after charging, the BMS Reset is not required. Through this method of charging the BCM updates the battery state of charge during the charging process.

When charging the vehicle battery by connecting the charger to the negative battery terminal is necessary, such as when using a combination battery charger and battery tester/analyzer, like the GR 1 190 V3.0 Intelligent Diagnostic Charger, the BCM does not immediately update the battery state of charge. In this instance, the BMS Reset must be carried out using a diagnostic scan tool. This reset is needed for proper engine off load shedding and to prevent invoking of engine off load shedding earlier than normal.

If the reset is not carried out, when the battery is charged by connecting the charger to the negative battery terminal, it takes approximately 8 hours for the BCM to learn the new battery state of charge.

During this 8 hour period, the vehicle must be undisturbed, with no doors opened or keyless entry button presses. If the vehicle is used before the BCM is allowed to learn the new battery state of charge, engine off load shedding can still occur and a message may be displayed.

Jump Starting
When it is necessary to jump start the vehicle it is important to connect the cables properly in order for the Electrical Energy Management system to measure the energy input to the system to keep an accurate state of charge. Connect the positive cable to the battery positive post and the jump start negative cable to a vehicle ground. Do not connect to the negative battery terminal. Connecting directly to the battery negative post bypasses the ability of the vehicle to measure the input current, and does not adjust the battery state of charge accordingly. For a good connection point, follow the negative cable from the battery monitoring sensor to the vehicle body connection (typically on the shock tower sheet metal). If the vehicle was improperly jump started, the Electrical Energy Management system calibrates the battery state of charge after about 8 hours.

Battery Replacement
If the vehicle battery is replaced, it is very important to perform the BMS Reset using a diagnostic scan tool. If the BMS Reset is not carried out, it holds the old battery parameters and time in service counter in memory. Additionally it tells the system the battery is in an aged state and may limit the Electrical Energy Management system functions

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.

There are 3 states of engine running load shed:

Load shed 1:
If vehicle speed is below 16 km/h (10 mph), and voltage to the PSCM is less than 11.5 volts or the PSCM measures current draw greater than 0 amps. If vehicle speed is above 16 kp/h (10 mph), and the voltage to the BCM is less than 11.6 volts.

These loads are incrementally reduced (if equipped): Heated steering wheel and climate controlled seats. These loads are turned off (if equipped): smart trailer tow battery charge, heated mirrors, heated back glass, and heated windshield.

Load shed 2 transient:
PSCM indicating reduced voltage and increased current. System voltage less than 11 volts

• If equipped, climate controlled seats are disabled, but the indicators remain illuminated.
• If equipped, rear defrost and heated mirrors are disabled, but the indicator remain illuminated.

Load Shed 2 Transient condition in excess of 20 seconds

• If equipped, climate controlled seats are disabled and the indicators are off.
• If equipped, rear defrost and heated mirrors are disabled and the indicator is off.
• If equipped with DATC, the blower motor is reduced to 50% speed.
• If equipped, DC/AC inverter (AC powerpoint) is disabled.
• The base IPC message center displays LOW BATTERY LESS FEATURES.
• The optional IPC message center displays LOW BATTERY FEATURES TEMPORARILY TURNED OFF.

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[AngelDeath]

So Earl what I got out of that is I am going to be putting this on a battery tender in the next couple of weeks and the positive gets connected but the negative has to be connected to a bare metal on the car and not the negative battery terminal so the battery management knows whats happening? I was just going to hook the two terminals directly to the battery. Guess not.

 

[Snoopy49]

So Earl what I got out of that is I am going to be putting this on a battery tender in the next couple of weeks and the positive gets connected but the negative has to be connected to a bare metal on the car and not the negative battery terminal so the battery management knows whats happening? I was just going to hook the two terminals directly to the battery. Guess not.

That's the way I read it.

 

[kilobravo]

I'm kinda excited about installing the darn thing. And to think, you can monitor the dang battery on YOUR PHONE! Technology, you gotta love it.

KB

 

[Tomster]

^^^^^ Oooooo...... Fancy.

 

[AngelDeath]

I'm kinda excited about installing the darn thing. And to think, you can monitor the dang battery on YOUR PHONE! Technology, you gotta love it.

KB

KB Where did you read in Earl's post about monitoring it on your phone? I'm not that blind!

 

[kilobravo]

Good looking car (and avatar) there, fella. :-)

 

[kilobravo]

Mike: Sorry for the confusion, I was referring to the CTEK gear on Kamazonski and specifically to their "Battery Sense Monitor" that I also ordered. It's the rig with BT for the phone connectivity.

Not necessary for sure but pretty darn cool.

KB

 

[Snoopy49]

Mike: Sorry for the confusion, I was referring to the CTEK gear on Kamazonski and specifically to their "Battery Sense Monitor" that I also ordered. It's the rig with BT for the phone connectivity.

Not necessary for sure but pretty darn cool.

KB

I have 2 of them, one for each car. You have to be within 30 foot of the car to be able to monitor the battery status. Now I don't have to guess when I need to charge the batteries.

 

[kilobravo]

I'm loving the idea more and more, Earl, and I may just do the same for our other vehicles. The room where I spend most of my indoor waking hours is right across an interior wall from the garage so BT shouldn't be a problem.

 

[Jmeo]

I wired my trickle charger directly to the fuse panel under the hood. The (+) is connected to one of the (+) studs on the fuse box, and the (-) is connected on the strut tower, where there is a stock ground wire. The pigtail connection is also circled in this picture (my last car, but exactly how I wired this one). Will this setup work? I remember this discussion from 5+ years ago, and this was the common way to connect the wires.

 

[Snoopy49]

I wired my trickle charger directly to the fuse panel under the hood. The (+) is connected to one of the (+) studs on the fuse box, and the (-) is connected on the strut tower, where there is a stock ground wire. The pigtail connection is also circled in this picture (my last car, but exactly how I wired this one). Will this setup work? I remember this discussion from 5+ years ago, and this was the common way to connect the wires.

Your good to go.

 

[Cobra99]

Anyone use this?

 

[V00D00]

I wired my trickle charger directly to the fuse panel under the hood. The (+) is connected to one of the (+) studs on the fuse box, and the (-) is connected on the strut tower, where there is a stock ground wire. The pigtail connection is also circled in this picture (my last car, but exactly how I wired this one). Will this setup work? I remember this discussion from 5+ years ago, and this was the common way to connect the wires.

What coolant tank is that?

 

[kilobravo]

Steve: I wondered about the tank as well. Did some soyching and the closest I came to the one above is the SA tank with white lettering. The one above may have been painted.

KB

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