Welcome Lighting May Drain 12V Battery

[DevSecOps]

The trigger threshold for an immediate recharge is 30% SoC

You sure about that? I am probably the only person who has a constant 12v monitor on my LVB with data going back over 6 months. 12.3v/12.2v is the lowest I can go (sustained, low load) before the car kicks in the DC/DC to top up the LVB. By my limited battery knowledge that would be 50-60% SOC.

The 12V will also stop automatically recharging when it’s less than 5ºF

Is that documented? Not doubting you, just never seen that before.

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[Murse-In-Airy]

Interesting Conversation @MachLee . I have never gotten the low 12V battery notification despite my welcome lights and my always on dash cam., except for when my car was in the shop getting wrapped. So I guess I’m not the target audience for this thread.

 

[Mach-Lee]

You sure about that? I am probably the only person who has a constant 12v monitor on my LVB with data going back over 6 months. 12.2v is the lowest I can go (sustained) before the car kicks in the DC/DC to top up the LVB. I didn't think 12.2v was 30% SOC.

Is that documented? Not doubting you, just never seen that before.

That's the way it was in a charging description I read somewhere. 12.2V is closer to 40% on an AGM. 5ºF/15% is when it said it will stop auto-recharge. They certainly could have changed behavior since writing the description.

EDIT: Found it in the Mach-E upfitter bulletin: https://fordbbas.com/vehicleModel/PoliceVehicle

I forgot about the "OTA recharge" option to top off before an OTA. Wonder if that's been working.

It will recharge after 40% with a delay, or immediately if it hits 30%.

 

[Logal727]

Turning off welcome lighting was a potential lead that seemed to solve issues for @Logal727 and @ProximusAl after exhausting other causes.

It’s because on some vehicles with I think older software the sync screen backlight is coming on and staying on after welcome lighting turns off, so even if it ignores you after a little bit, the screen backlight drains the battery. This also only happens to those who have their PAAK very close all the time it seems.

 

[Mach-Lee]

It’s because on some vehicles with I think older software the sync screen backlight is coming on and staying on after welcome lighting turns off, so even if it ignores you after a little bit, the screen backlight drains the battery. This also only happens to those who have their PAAK very close all the time it seems.

Ah, so it's probably the APIM? staying awake and draining rather than the welcome lighting itself. Welcome lighting just triggers the condition. Wonder if an APIM update would fix that.

 

[Logal727]

Ah, so it's probably the APIM? staying awake and draining rather than the welcome lighting itself. Welcome lighting just triggers the condition. Wonder if an APIM update would fix that.

Yes, I haven’t tested if it’s been fixed since I got all my updates yet, I will see if I can test it out.

 

[DevSecOps]

That's the way it was in a charging description I read somewhere. 12.2V is closer to 40% on an AGM. 5ºF/15% is when it said it will stop auto-recharge. They certainly could have changed behavior since writing the description.

EDIT: Found it in the Mach-E upfitter bulletin: https://fordbbas.com/vehicleModel/PoliceVehicle

I forgot about the "OTA recharge" option to top off before an OTA. Wonder if that's been working.

It will recharge after 40% with a delay, or immediately if it hits 30%.

Ok so according to that document it's when the battery temp is below -15C that it won't charge.

 

[generaltso]

Ok so according to that document it's when the battery temp is below -15F that it won't charge. That's damn cold.

It’s -15C, which is 5F. Not so cold around here.

 

[Mach-Lee]

It’s because on some vehicles with I think older software the sync screen backlight is coming on and staying on after welcome lighting turns off, so even if it ignores you after a little bit, the screen backlight drains the battery. This also only happens to those who have their PAAK very close all the time it seems.

Ah, so it's probably the APIM? staying awake and draining rather than the welcome lighting itself. Welcome lighting just triggers the condition. Wonder if an APIM update would fix that.

I found this SSM, I can't remember if it got posted or not. I think this IPC update was 2.4.4/2.7.4. BlueCruise updates should have fixed it.

SSM 50444 2021 Mustang Mach-E - IPC Backlight Remains Illuminated With Ignition Key Off/12V Battery Drain

Some 2021 Mustang Mach-E vehicles may exhibit illuminated instrument panel cluster (IPC) backlight with key-off, causing 12V battery drain. To resolve this condition, park the vehicle and close doors, allow vehicle to enter key-off status, wait for the brake indicator to turn off, turn on hazard lights for 3 flashes and turn off. An IPC software update is expected to be delivered to vehicles via an over-the-air (OTA) update in March 2022 to permanently resolve the condition. Let the customer know they can continue to drive the vehicle and advise to connect to their FordPass account to enable OTA delivery. Schedule a follow-up appointment for April 2022, and contact the customer to verify the OTA was received and confirm if the service appointment is necessary going forward. Monitor OASIS for updates.

 

[DevSecOps]

It’s -15C, which is 5F. Not so cold around here.

LMAO. I can't believe I didn't see the C

 

[DevSecOps]

Here's a good illustration of my car while I was on vacation for 10 days. My dad had the car and didn't drive it for a week. The dips in voltage are the welcome lights coming on. I do have 2 always on devices connected to the LVB which is why there's slight drain.

 

[Mach-Lee]

Here's a good illustration of my car while I was on vacation for 10 days. My dad had the car and didn't drive it for a week. The dips in voltage are the welcome lights coming on. I do have 2 always on devices connected to the LVB which is why there's slight drain.

Interesting. That dip after the recharge in the middle has a much steeper voltage decline than the previous week when it was parked for some reason?

 

[StillWaitingForMachE]

Just a thought, but what if Ford added a state of charge readout for the 12V battery just like how there's one for the HVB? Is the hardware in place to do this? Or would it result in higher 12V battery drain due to Schrodinger's Law lol

So what is the clicking I hear so often then?

Ive heard it too and I always thought it was the car locking/unlocking, although I am probably wrong. The Mach E is by far the most technologically advanced car I've ever owned so I'm still learning about everything it has.

 

[DevSecOps]

Interesting. That dip after the recharge in the middle has a much steeper voltage decline than the previous week when it was parked for some reason?

I collect the data on 10 second intervals. Almost all of the dips are extremely short. Here's a zoomed out view of typical ups and downs:

And here's a coser look at welcome light dips

Also this is using a shunt so I'm not basing this off the cars reporting. Therefore, I would guess it's more accurate.

 

[Mach-Lee]

Just a thought, but what if Ford added a state of charge readout for the 12V battery just like how there's one for the HVB? Is the hardware in place to do this? Or would it result in higher 12V battery drain due to Schrodinger's Law lol

Ive heard it too and I always thought it was the car locking/unlocking, although I am probably wrong. The Mach E is by far the most technologically advanced car I've ever owned so I'm still learning about everything it has.

You can see the 12V SoC % with an OBD scan tool. The SoC is determined by the BMS current sensor which lives on the negative terminal of the battery. SoC updates are sent periodically via a LIN bus.

I collect the data on 10 second intervals. Almost all of the dips are extremely short. Here's a zoomed out view of typical ups and downs:

And here's a coser look at welcome light dips

Also this is using a shunt so I'm not basing this off the cars reporting. Therefore, I would guess it's more accurate.

I'm talking more about the general decline, it drained much faster in the circled area than the previous 5 days. After the recharge, something turned off at the cyan dot and the decline returned to normal:

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