When does Plugging in charge the 12V?

[lesz]

Hi.
I was out of town for a few days and my 12V charge dropped. I plugged in about 3 hours ago (Ford Level 1), and in the pics you can see the effect on 12V charge.

Not sure it matters to anyone but thought I would post it.

My experience has been different from yours. When plugged into a level 1, the 12V battery SOC increases only as long as the HVB is also being charged. Once the HVB reaches its target SOC, I’ve seen no indication that the 12V battery continues to charge. As of two days ago, my HVB SOC reached 90%, and my 12V is at 78%. The car has been off and plugged in the whole time.

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[MrLoganRoss]

So now that I look back over this thread it seems like there is no need for doing extra things for the 12V, correct? If it is plugged in, it will charge (as long as HVB is charging), if you drive it, it will charge, and if it gets too low, it will take charge from the HVB.

please let me know if I missed anything.

 

[Mach-Lee]

So now that I look back over this thread it seems like there is no need for doing extra things for the 12V, correct? If it is plugged in, it will charge (as long as HVB is charging), if you drive it, it will charge, and if it gets too low, it will take charge from the HVB.

please let me know if I missed anything.

Correct. The only time you need to do something is if the vehicle will be parked without driving it for a month, or if you have a 12V battery drain.

The thread title is still misleading, I will reiterate the act of plugging in does not always charge the 12V battery. Only when the vehicle is taking HVB charge. Those that are seeing otherwise have a software glitch they didn't know about.

 

[lesz]

So now that I look back over this thread it seems like there is no need for doing extra things for the 12V, correct? If it is plugged in, it will charge (as long as HVB is charging), if you drive it, it will charge, and if it gets too low, it will take charge from the HVB.

please let me know if I missed anything.

‘… if it gets too low, it will take charge from the HVB.’ Depends on your definition of “too low“. I only became aware of the SOC of my 12V when I had an OTA update that would not complete because (according to Ford) my 12V SOC was too low (it was 78%).

 

[MachEnthusiast]

Yes … but … why did you doubt that it charged the 12v when you plug in the car?

This has been a massive discussion for years. In my experience plugging the car never charges the 12V. The only way I've confirmed successfully charging it is driving the car around or just running it in my driveway for literally hours. This is something I've had to do more than a handful of times just to get OTA updates that require a 90% or 95% charge on the 12V.

I thought one of the recent OTA updates was supposed to fix this. 24-PU0121-FTDI-FX I think. Which I have, but I have still had trouble with OTAs failing to install since getting that one.

 

[grein002]

My experience w/2023 GTPE (5/23 build date) is as follows:

1. If I drive (or otherwise turn the car on, as in "press brake and press start"), it charges 12V
2. If car is off, no 12V charge.
3. If car is in accessory mode (press start "without" pressing brake), no 12V charge. Actually 12V discharge.
4. If plugged into charger, 12V charge when HVB is charging, but not before or after.

 

[Homestead]

This has been a massive discussion for years. In my experience plugging the car never charges the 12V. The only way I've confirmed successfully charging it is driving the car around or just running it in my driveway for literally hours. This is something I've had to do more than a handful of times just to get OTA updates that require a 90% or 95% charge on the 12V.

I thought one of the recent OTA updates was supposed to fix this. 24-PU0121-FTDI-FX I think. Which I have, but I have still had trouble with OTAs failing to install since getting that one.

My 12V charge goes up when doing level 2 charging and if I use level 1 charging for an extended time it goes way up.
Also thought the OTA update was supposed to fix this but I haven't received any updates since the Tesla charging update a couple months ago.

 

[Teslaeata]

Plugging in HV charger doesn’t cause or start 12v charging.

The technical specifications I have seen state that provided HV battery is over 15% (I think is the percentage) charged, the DC/DC converter will start to charge car 48hours after 12v battery drops to 40% state of charge.

If 12v SoC drops to 30% the 12v battery charging will start straight away irrespective of whether HV battery is charging or not, whether car is turned on or off or even if has “gone to sleep”.

The battery management system takes care of all that.

If you find you actually HAVE TO place a charger on the 12v battery, there’s a problem which needs a diagnosis.

If you just THINK because you have worried yourself into the belief you need to attach a 12v charger, you are the problem.

I’d be inclined not to worry too much about 12v state as a lot of people do.

If it ever does actually dies, then it dies and it will be replaced.

Until then I got a life to live and a leccy ‘Stang to enjoy ?

 

[Sikkun]

You can watch the 12v battery shoot to receiving 14+v charge as soon as your plug in (L1/L2) and then taper off around 13.5v until the car is fully charged.

Or stay at 13.5v forever if you have a bugged 23.

I kinda like the idea of the charger providing a trickle charge to the 12v…but still going to get the bug fixed.

 

[Jerrytball]

Do you wanna try something different, look at the battery life on ford.com and then start the car remotely with FordPass and watch the battery mine actually went down 3% and then after I shut it off from running five minutes it came back up one percent so basically it went from 85 down to 82 and then came back up to 83!
Just got done driving 25 miles, plugged in and started charging level 2, 3 hrs ago.

 

[medriver]

Plugging in HV charger doesn’t cause or start 12v charging.

The technical specifications I have seen state that provided HV battery is over 15% (I think is the percentage) charged, the DC/DC converter will start to charge car 48hours after 12v battery drops to 40% state of charge.

If 12v SoC drops to 30% the 12v battery charging will start straight away irrespective of whether HV battery is charging or not, whether car is turned on or off or even if has “gone to sleep”.

The battery management system takes care of all that.

If you find you actually HAVE TO place a charger on the 12v battery, there’s a problem which needs a diagnosis.

If you just THINK because you have worried yourself into the belief you need to attach a 12v charger, you are the problem.

I’d be inclined not to worry too much about 12v state as a lot of people do.

If it ever does actually dies, then it dies and it will be replaced.

Until then I got a life to live and a leccy ‘Stang to enjoy ?

This is not exactly true.

When the HVB is taking a charge I find that the LVB gains about 3% an hour.
Running the car also raises the LVB but I haven't bothered to figure out how much, i would assume the same.
When the LVB gets critically low its true the HVB gives it a slug.
Waking up the car can use a couple percent of LVB.

Any accessories cause 12V battery problems, my hypothesis is PAAK and other remote API wakeups cause the remainder. Remember your LVB could drop a couple percent just by looking at your car in FordPass (the old "refresh" behavior) if your car was sleeping it's going to wake it up and use LVB.

So you can get into trouble if your car wakes up a bunch and you do short drives and you do fast charging because the LVB never really gets a chance to charge because it always relies on time with car on or time actually charging, unless it's being slugged by the HVB but it's in bad shape if that's happening because if the LVB goes too low it can die.

 

[HuntingPudel]

‘… if it gets too low, it will take charge from the HVB.’ Depends on your definition of “too low“. I only became aware of the SOC of my 12V when I had an OTA update that would not complete because (according to Ford) my 12V SOC was too low (it was 78%).

These are two separate items. Many OTAs require 80% or higher LVB SoC and will not commence if the LVB is lower than 80%. The car’s charging system views 40% as “too low” and uses that as the trigger point for engaging charging of the LVB. ??

 

[RandyMache]

My experience w/2023 GTPE (5/23 build date) is as follows:

1. If I drive (or otherwise turn the car on, as in "press brake and press start"), it charges 12V
2. If car is off, no 12V charge.
3. If car is in accessory mode (press start "without" pressing brake), no 12V charge. Actually 12V discharge.
4. If plugged into charger, 12V charge when HVB is charging, but not before or after.

So, my experience is that when my MME is off, NOT plugged in, sitting for days and even weeks, if my 12v gets down to about 12.2v, the big battery charges the 12v back up to about 12.8v. When I travel for weeks at a time, this is the same result over and over again. It takes about 5 days for it to go from 12.8 back down to 12.2v. I believe this is how it should work. I don't understand other peoples experiences other than to say something must be working improperly.

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