RLXXI

Wrong, the battery supplies all the juice for everything and when the battery monitor tells the system it needs more, the alternator is then allowed to supply.

The system also uses a load shed strategy and will turn systems on/off as needed. As far as I know that is how the system is for 2011+. Here's some info directly from the Ford shop manual.


414-00 Charging System 2013 F-150 DESCRIPTION AND OPERATION Procedure revision date: 08/30/2012


Charging System


The charging system is a negative ground system consisting of:

• a generator with an internal voltage regulator
• a charging system warning indicator
• a battery
• circuitry and cables
• a PCM
• a radial arm adapter (serviced separately from the generator)
• a battery current sensor
• a generator current sensor

The generator is driven by the FEAD belt. When the engine is started, the generator begins to generate AC voltage which is internally converted to DC voltage. The PCM determines the desired voltage level and communicates this to the generator internal voltage regulator over 2 control and communication circuits. The voltage regulator (located on the rear of the generator) controls the DC voltage output level which is applied to the electrical system and charges the battery.


This vehicle is equipped with load shed strategy. The Body Control Module (BCM) monitors the battery state of charge using the battery current sensor attached to the negative battery cable and the battery open circuit voltage as measured by the BCM during 8 continuous hours of vehicle sleep time (ignition off with doors closed).


With the engine off and the ignition in the ACC, RUN or delayed accessory position, when the BCM determines the battery state of charge is low, a message is sent to shut down the audio/navigation system in order to save the remaining battery charge. Under this condition:

• the Front Display Interface Module (FDIM) displays SYS OFF TO SAVE BATT (without navigation) or BATTERY SAVER — SYSTEM OFF PLEASE START THE ENGINE (with navigation).
• the Instrument Panel Cluster (IPC) message center may also display TURN POWER OFF TO SAVE BATT (base message center) or TURN POWER OFF TO SAVE BATTERY (optional message center) to notify the driver that battery protection actions are active.
• the battery indicator may also illuminate.

If the vehicle battery has been charged or battery replaced, 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 buttons pressed. If the vehicle is used before the BCM is allowed to learn the new battery state of charge, engine off load shedding may occur earlier than normal and a message may be displayed.


If the vehicle has been jump started, engine off load shedding can still occur and a message may be displayed until the BCM determines the battery state of charge is above 40%.


With the engine running, when the BCM and Power Steering Control Module (PSCM) voltage is low, a message is sent from the BCM to either minimize or shut down the climate controlled seats, rear defrost, heated mirrors and Dual Automatic Temperature Control (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.


The PCM monitors the generator current using the generator current sensor attached to the generator B+ battery cable. This is used for engine idle stability and torque control.


Copyright © 2016 Ford Motor Company
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Feathermerchant

Wrong, the battery supplies all the juice for everything and when the battery monitor tells the system it needs more, the alternator is then allowed to supply.

So put a 30A load on a battery and tell me how long before it needs to be charged. The alternator will pick up the load almost immediately. It has to or the battery serves the load discharging it.

RLXXI

You are assuming it will pick up the load immediately, every day I put a load (more than 30A) on every truck I work on in our fleet, good batteries will maintain a set voltage for a minimum of 50 secs, longer if our computer controlled load tester would allow it. The fact remains the same, the battery carries the load until the system sees it drop, and ONLY then does the alternator kick in. Your not driving a 57 Chevy.
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bb123

2013 F150 super crew 5.0L

_MacLeod_

It may only charge the battery when it needs it but it's running the entire electrical system when the motor is running.

Feathermerchant

^^ This ^^

RLXXI

I stand corrected. I knew older vehicles the alt/gen run the entire system that way and misinterpreted the only thing that did change (namely charging the battery) to system operation as a whole, I went back and re-read system description and operation and that's exactly how it's described.


Here are the Principles of operation from the shop manual.


Principles of Operation



Charging System


The PCM -controlled, or Smart Charge charging system determines the optimal voltage setpoint for the charging system and communicates this information to the voltage regulator. The Smart Charge charging system is designed to set a DTC any time a charging system fault is present. All DTCs can set as continuous faults, but not all DTCs set as on-demand faults.


This system uses 2 communication lines between the PCM and the generator/voltage regulator. Both of these communication lines use Pulse-Width Modulation (PWM) . The generator communication (GENCOM) line communicates the desired setpoint from the PCM to the voltage regulator. The generator monitor (GENMON) line communicates the generator load and error conditions to the PCM . The GENCOM command is only sent by the PCM when it is necessary to adjust the voltage setpoint. If the setpoint does not need to be changed, several seconds may elapse between PCM GENCOM commands. This normal operation appears in the PID as occasional bursts of pulse-width commands. The third pin on the voltage regulator, the "A" pin, is a circuit dedicated to monitor or sense battery voltage.


The PCM simultaneously controls and monitors the output of the generator. When the current consumption is high or the battery is discharged, the PCM raises engine speed as needed to increase generator output. The generator charges the battery and at the same time supplies power for all of the electrical loads that are required. The battery is more effectively charged with a higher voltage when the battery is cold and a lower voltage when the battery is warm. The PCM is able to adjust the charging voltage according to the battery temperature, calculated by using a signal from the Intake Air Temperature (IAT) sensor. The PCM also uses other inputs to control charging system voltage such as the Vehicle Speed Sensor (VSS) and Engine Coolant Temperature (ECT) . The voltage setpoint is calculated by the PCM and communicated to the voltage regulator by the GENCOM circuit based on the needs of the vehicle and the conditions.


The PCM turns off the generator during cranking to reduce the generator load and improve cranking speed. Once the engine starts, the PCM slowly increases generator output to the desired voltage.


The PCM reports any charging system faults and sends a message through High Speed Controller Area Network (HS-CAN) to the Body Control Module (BCM) . The BCM controls the charging system warning indicator by sending a message over the Medium Speed Controller Area Network (MS-CAN) to the Instrument Panel Cluster (IPC) . The IPC then controls charging system warning indication based on the message from the PCM through the BCM . The status of the PCM charging system warning indicator and/or message can be confirmed by viewing PCM PID generator fault indicator lamp (GENFIL). Any charging system fault detected by the PCM results in 1 or more DTCs being set and the PID GENFIL having a status of On. If equipped with a charging system warning indicator, the IPC turns the indicator on or off. If equipped with a message center, the IPC displays a CHECK CHARGING SYSTEM message. When the ignition is ON and the engine is off on vehicles equipped with a message center, the CHECK CHARGING SYSTEM message may not be displayed. For information regarding the IPC and message center, refer to Section 413-01.


Under certain circumstances, the charging system may have a concern, but still keeps the battery charged and the vehicle running. GENCOM is normally used to initiate charging, but the generator may charge with a fault in this circuit. If the engine operates at more than 2,000 rpm momentarily, the generator may self-excite or start charging on its own. The charging system warning indicator is illuminated and/or CHECK CHARGING SYSTEM message is displayed, and the generator operates in a default mode (approximately 13.5 volts) until the engine is turned off. When the engine is restarted and the engine operates at more than 2,000 rpm momentarily, the generator may again self-excite and again the charging system warning indicator is illuminated and/or CHECK CHARGING SYSTEM message is displayed.
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Feathermerchant

This is similar to the older systems that simply set the system voltage based on ambient temperature. In the new system the system monitors the actual battery charge state via the current measuring device that surrounds the negative battery lead and therefore measures the current into and out of the battery. It operates on the same principle as a DC clip on ammeter. There is a similar current sensor on the output lead of the alternator.