Ford Battery Recall - #25S02

[Dude]

Agreed. It's not about overwhelming the alternator, it's about the way the BMS manages alternator output. Meeting consumer demand to get the best possible fuel economy means limiting the amount of engine power needed for accessories like the alternator. If the BMS limits alternator output then it requires less engine power to operate.

You are right of course on that point and I updated ChatGPT .. it even thought your answer was a solid addition! Living in infamy now with ChatGPT’s updated knowledge lol

(ChatGPT) Great suggestion! Here is an updated list with your #4 addition included: (see post #36 for the prior list)

4. Modern vehicles that use a Battery Management System (BMS) manage the alternator output. To improve fuel economy, the BMS limits the alternator’s output to reduce the engine power needed for accessories. As a result, modern vehicles cannot run with a dead or disconnected battery because they rely on controlled alternator output.

Thanks for the input- it is a solid addition!

(Above is from ChatGPT)

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[Mark S.]

You are right of course on that point and I updated ChatGPT .. it even thought your answer was a solid addition! Living in infamy now with ChatGPT’s updated knowledge lol

I guess I'm now immortal...

 

[wireman]

I guess I'm now immortal...

You always have been!

 

[sajohnson]

You are right of course on that point and I updated ChatGPT .. it even thought your answer was a solid addition! Living in infamy now with ChatGPT’s updated knowledge lol

(ChatGPT) Great suggestion! Here is an updated list with your #4 addition included: (see post #36 for the prior list)

4. Modern vehicles that use a Battery Management System (BMS) manage the alternator output. To improve fuel economy, the BMS limits the alternator’s output to reduce the engine power needed for accessories. As a result, modern vehicles cannot run with a dead or disconnected battery because they rely on controlled alternator output.

Thanks for the input- it is a solid addition!

(Above is from ChatGPT)

My understanding is that recall 24S24 was supposed to address the problem of the engine dying when the battery failed. IOW, it should have reprogrammed the BMS to allow the engine to keep running using the alternator alone:
https://www.ford.com/support/how-tos/recall/recalls-and-faqs/24s24-bronco-sport-2021-2024-and-maverick-2022-2023-loss-of-power-recall/

1) "April 12: Recall over loss of drive power from low battery
Ford recalled certain 2021-2024 Bronco Sport and 2022-2023 Maverick vehicles. In the NHTSA report, the company said the body and power train control modules may fail to detect a change in the 12-volt battery. When a vehicle has an undetected low battery charge, it can result in a loss of hazard lights or cause a loss of drive power, the report said. As a result, it will increase the risk of a crash. Potential number of units affected: 456,565."
https://www.usatoday.com/story/money/cars/recalls/2024/12/30/ford-recalled-cars-suvs-2024/77241606007/

2) "REASON FOR THIS SAFETY RECALL In the affected vehicles, the Body Control Module (BCM) and Powertrain Control Module (PCM) calibrations may be unable to detect a sudden battery degradation while driving. If the battery suddenly degrades during a drive it can lead to a vehicle that is unable to restart after an auto stop/start event or experience a stall while coming to a stop at low speed. Either of these conditions may be accompanied by a loss of 12-volt accessories, including hazard lights. A loss of motive power can increase the risk of a crash."
https://static.nhtsa.gov/odi/rcl/2024/RCMN-24V267-9251.pdf

 

[Dude]

….

Regarding your statement: “My understanding is that recall 24S24 was supposed to address the problem of the engine dying when the battery failed. IOW, it should have reprogrammed the BMS to allow the engine to keep running using the alternator alone:”

I do not believe that is correct in that the ‘BMS was programmed to allow the vehicle to run on alternator alone’, my read of the limited info regarding 24S24 is the configuration changes would force a condition where Auto Stop Start would remain Off (not engaged) when the battery was at an insufficient level to allow the vehicle to perform a restart if ASS stopped the engine. In 25S02, Ford stated that some of the battery failure conditions could not be detected with the 24S24 configuration (including the case where a vehicle ‘experiences a stall while coming to a stop at low speed’) and thus 24S24 configuration changes failed to work as Ford intended for all cases of a battery failure (see 25S02 description). I have not seen any documentation stating the vehicle is designed to run on alternator alone or even if it could the fuel mileage would suffer as Mark S previously posted. Do you have a specific statement from Ford that the Bronco Sport is designed to run on alternator alone?

 

[sajohnson]

Regarding your statement: “My understanding is that recall 24S24 was supposed to address the problem of the engine dying when the battery failed. IOW, it should have reprogrammed the BMS to allow the engine to keep running using the alternator alone:”

I do not believe that is correct in that the ‘BMS was programmed to allow the vehicle to run on alternator alone’, my read of the limited info regarding 24S24 is the configuration changes would force a condition where Auto Stop Start would remain Off (not engaged) when the battery was at an insufficient level to allow the vehicle to perform a restart if ASS stopped the engine. In 25S02, Ford stated that some of the battery failure conditions could not be detected with the 24S24 configuration (including the case where a vehicle ‘experiences a stall while coming to a stop at low speed’) and thus 24S24 configuration changes failed to work as Ford intended for all cases of a battery failure (see 25S02 description). I have not seen any documentation stating the vehicle is designed to run on alternator alone or even if it could the fuel mileage would suffer as Mark S previously posted. Do you have a specific statement from Ford that the Bronco Sport is designed to run on alternator alone?

We are both simply interpreting Ford's recall 24S24. It is not possible to say with 100% certainty a) what their intentions were, and b) how successful they were.

It is certainly implied that the recall will correct the problem -- and the only way to do that is for the vehicle to be able to continue operating on the alternator alone.

The recall says: "When a vehicle has an undetected low battery charge, it can result in a loss of hazard lights or cause a loss of drive power, the report said. As a result, it will increase the risk of a crash."

So Ford was/is fully aware that -- prior to the recall -- if a battery fails, the vehicle cannot continue operating, and it will increase the risk of a CRASH -- which may result in injuries or death.

At that point, the impact on mileage ceases to be a factor. It's bad enough that the issue existed in the first place, but OK, no vehicle is perfect. Ford did the right thing and issued a recall. That should have been the end of it.

Now it is being suggested that the BS still cannot run on the alternator alone?! If that's true it seems that Ford has exposed itself to liability for any damages related to their vehicles that stop running with no warning.

 

[Dude]

I’ve posted a handful of times already, “none of us know the charging system algorithms implemented by Ford in the BCM and in the PCM” and we don’t know the mods contained in the changes for 24S24. On that point we both agree.

But no where have I seen that the vehicle will run on the alternator output alone and was hoping you could provide a statement from Ford that it can.

We have discussed many times before (a few of the links are below), the actual wording in 24S24 (https://static.nhtsa.gov/odi/rcl/2024/RCLRPT-24V267-6161.PDF) states ‘improved detection’.

A few of the prior discussions on the topic of Recall 24S24 states it provides “improved detection of 12V battery SOC during drive cycles” but does not state the problems listed in 24S24 are fixed:

https://www.broncosportforum.com/forum/threads/recall-24s24-nhtsa-closes-ford-bronco-sport-12v-battery-investigation.11931/post-200376

https://www.broncosportforum.com/forum/threads/recall-24s24-quarterly-report-loss-of-drive-power-from-undetected-low-battery.11890/post-199832

https://www.broncosportforum.com/forum/threads/defective-battery-recall-24s24-and-other-topics.11523/post-199418

The key point admitted in Recall 25S02 is “Prior software released as part of FSA 24S24 is unable to detect certain electrical signatures present on failed batteries and/or failed to disable stop/start functionality quickly enough.”

Bottom line is the exhibited internal failure mechanism inside the Camel EFBs which failed could not be handled by the BCM/PCM algorithms which corresponds to the statement of having “improved detection” but clearly was not 100% detection.

 

[sajohnson]

But no where have I seen that the vehicle will run on the alternator output alone and was hoping you could provide a statement from Ford that it can.

No, to my knowledge, Ford does not make that claim -- not directly.

Of course the inverse is true -- Ford has not said that the BS cannot continue running with a weak/dead battery.

But let's say that after the 24S24 recall the BS still cannot run on the alternator alone. That means the potential for a very dangerous failure -- one that Ford is aware of -- still exists.

Why not design the BS (and all vehicles) so that they can run on the alternator alone? There is zero downside. The BMS can be reprogrammed. MPG might take a *slight* hit, but it has to be minimal. After all, it's the load that determines the alternator output (and therefore the drag on the engine). The alternator output must be equal to all loads combined. There's no way around that, other that to discharge the battery. Limiting the alternator's output to reduce the load on the engine makes no sense -- the load is what it is.

I just did some reading to see if I was missing something. All I found was what most of us know -- that the battery acts as a filter capacitor, so it should not be removed or disconnected while the engine is running, but as long as it is in place the alternator should be able to keep the car running with no damage to any electronics.

 

[Dude]

The text in 25S02 states that a battery failure can lead to an open circuit … with an open circuit inside the battery, there is no 12V battery in the system correct?

So that violates the prior statement “battery acts as a filter capacitor, so it should not be removed or disconnected while the engine is running, but as long as it is in place the alternator should be able to keep the car running with no damage to any electronics.”

With an open circuit, the battery is no longer in place so the alternator would not necessarily be able to keep the car running with no damage to any electronics correct?

Worst case, that open circuit is like attempting to drive a vehicle with no 12V battery.

 

[sajohnson]

The text in 25S02 states that a battery failure can lead to an open circuit … with an open circuit inside the battery, there is no 12V battery in the system correct?

So that violates the prior statement “battery acts as a filter capacitor, so it should not be removed or disconnected while the engine is running, but as long as it is in place the alternator should be able to keep the car running with no damage to any electronics.”

With an open circuit, the battery is no longer in place so the alternator would not necessarily be able to keep the car running with no damage to any electronics correct?

Not if the vehicle is designed correctly. Capacitors are cheap -- especially compared to a tow, or an accident.

Being able to run on the alternator is an ability all cars should have.

The alternative is missing appointments; being stranded -- potentially in an unsafe location; paying for a tow; and other unpleasant situations like stalling on an interstate highway with 80+ mph traffic.

IMHO, this is an easy call.

EDIT to ADD:

Since batteries can fail open, as you mentioned, Ford (and other mfrs) must have circuitry in place to protect onboard electronics.

 

[Dude]

In a 12V vehicle, load dump refers to a transient voltage spike that occurs in the electrical system when a significant electrical load, such as the vehicles battery, is suddenly disconnected while the alternator is still generating power. This can happen due to loose battery connections, failure of battery cables, or disconnection during maintenance (or an internal open circuit in the 12V Battery).

Key Points about Load Dump:

Cause: The alternator, which is regulated to maintain voltage, continues generating power, but without the battery to absorb excess energy, the system voltage surges, often reaching 120V or more in extreme cases.

Duration: The spike can last from milliseconds to hundreds of milliseconds.

Impact: This high voltage can damage sensitive electronics in the vehicle, such as the ECU (engine control unit), sensors, and infotainment systems.

Protection Measures:

1. Load Dump Suppressors: Devices like transient voltage suppressors (TVS) are installed to protect sensitive electronics.

2. Regulated Alternators: Modern vehicles use alternators with advanced voltage regulators that can mitigate load dump effects.

3. Battery Connections: Ensuring tight and secure battery connections can prevent accidental disconnections.

This phenomenon is especially critical in vehicles with many electronic components, as even a brief voltage spike can cause costly damage.

 

[sajohnson]

In a 12V vehicle, load dump refers to a transient voltage spike that occurs in the electrical system when a significant electrical load, such as the vehicles battery, is suddenly disconnected while the alternator is still generating power. This can happen due to loose battery connections, failure of battery cables, or disconnection during maintenance (or an internal open circuit in the 12V Battery).

Key Points about Load Dump:

Cause: The alternator, which is regulated to maintain voltage, continues generating power, but without the battery to absorb excess energy, the system voltage surges, often reaching 120V or more in extreme cases.

Duration: The spike can last from milliseconds to hundreds of milliseconds.

Impact: This high voltage can damage sensitive electronics in the vehicle, such as the ECU (engine control unit), sensors, and infotainment systems.

Protection Measures:

1. Load Dump Suppressors: Devices like transient voltage suppressors (TVS) are installed to protect sensitive electronics.

2. Regulated Alternators: Modern vehicles use alternators with advanced voltage regulators that can mitigate load dump effects.

3. Battery Connections: Ensuring tight and secure battery connections can prevent accidental disconnections.

This phenomenon is especially critical in vehicles with many electronic components, as even a brief voltage spike can cause costly damage.

Yep, I read that Google AI info earlier.

AFAIK, that's all true. What I am suggesting is that Ford (and other mfrs) install transient voltage suppressors (TVS) (see #1 above) in parallel with the battery, so that if there is an open circuit failure, any spikes will be minimized.

Also see #2:

"Regulated Alternators: Modern vehicles use alternators with advanced voltage regulators that can mitigate load dump effects."

So between #1 and #2, load dump effects may be a non-issue.

Bottom line:

* The BS (and other vehicles) will apparently stop running if there is an open circuit battery failure -- either internal or due to a loose/corroded connection.

* Most people do not want their BS to stall without warning -- the result can be bad.

* Luckily, the problem can be remedied. I can't think of any reason for Ford to not correct it.

Here's one company that does just that:

"A car power supply network is often contaminated with voltage surges potentially damaging to the semiconductor circuits present. The STMicroelectronics family of RBOxx protection devices enables full protection from these surges with the minimum component count."
https://www.st.com/resource/en/application_note/an555-automotive-protection-with-the-rboxx-series-stmicroelectronics.pdf

 

[BLUEOVALRACER]

This is what my EFB battery was doing. Cold cranking was good but SOC was 67 percent so dealer replaced the battery with an AGM battery. The battery was only 10 months old and 3400 miles.

But mine is a 24 and is not included in the recall. Looks like maybe 24's should be. Just happy it was replaced with an AGM.

Thanks for this information maybe i'll swing by the nearest Ford Dealership and see what they say.I got my BS New on December 20th 2023 it's coming up on 5,700 miles.

 

[Mark S.]

The bottom line is we don't know how Ford designed the electrical system for these cars. What we do know is that some vehicles experience spurious electrical system malfunctions up to and including uncommanded engine shut down, and that Ford is "fixing" the problem with a combination of software updates and new batteries.

 

[Dude]

Have seen a few Bronco Sport owners report that their 12V battery exploded or was smoking, is it possible those were one of the China made Camel EFB (batteries)…

Recall 25S02 PDF in Post #18 refers to Internal cast-on-strap failure or weak tombstone welds in some Camel EFBs predominantly in warmer weather states.

“As of October 29, 2024, 234 out of 238 allegations of LOMP (Loss Of Motive Power) post-24S24 were vehicles produced with Camel EFB batteries. Ford has not identified any Clarios EFB batteries with a similar failure mode to what has been observed in the Camel EFB.”

“Population:
Number of potentially involved: 272,817
Estimated percentage with defect: 1%”

“The replacement 12V battery BAGM-48H6-760 is absent the internal defects present in the Camel batteries.”

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