12V Battery Issues

[smunro622]

23 extended range AWD Mach E, had anyone else run I to this issue below.

Since the 12 v battery update I am having 12v battery drain issues. 2weeks ago vehicle parked at train station (3 days) drops to 39 percent. Noticed a few more times 12v hits mid 40 percent while on charger, HVB is swt to charge to 90 percent. Gomout for a 45 mi drive today and charges to about 60 percent. I have double checked nothing is plugged into a USB port and nothing is plugged in on the 12v outlet under the arm rest.

I did get the OBD Max + for the port paired with car scanner. 12v battery running at 15.1 v. Next step is making a dealership appointment to see if they can find anything wrong or a maybe needs a SW update.

Sponsored

 

[Mach-Lee]

Are you making sure you unplug that OBD Max device when the vehicle is parked? Otherwise that's a 12V drain.

 

[smunro622]

Are you making sure you unplug that OBD Max device when the vehicle is parked? Otherwise that's a 12V drain.

I just added this 2 days ago and yes I do unplug the OBD device. Should the LVB hitting 15.1 V?

 

[Mach-Lee]

I just added this 2 days ago and yes I do unplug the OBD device. Should the LVB hitting 15.1 V?

Yes that's normal if the 12V battery is charging.

Verify the following:

Disconnect any and all accessories from the vehicle including hardwired dashcams, dashcam batteries, radar detectors, OBD port scan devices, etc. (Verify no fuses are tapped, nothing plugged in to OBD port, 12V ports, USB ports, or connected to the 12V battery).

Make sure you have no apps that are pinging your vehicle for data (such as battery % charge), including charging status apps, utility charging apps, battery health apps, etc.

Disable welcome lighting and keep key fobs at least 25' away from vehicle while parked. Disable Bluetooth on your phone(s) so PAAK cannot connect while the vehicle is parked.

 

[Teslaeata]

23 extended range AWD Mach E, had anyone else run I to this issue below.

Since the 12 v battery update I am having 12v battery drain issues. 2weeks ago vehicle parked at train station (3 days) drops to 39 percent. Noticed a few more times 12v hits mid 40 percent while on charger, HVB is swt to charge to 90 percent. Gomout for a 45 mi drive today and charges to about 60 percent. I have double checked nothing is plugged into a USB port and nothing is plugged in on the 12v outlet under the arm rest.

I did get the OBD Max + for the port paired with car scanner. 12v battery running at 15.1 v. Next step is making a dealership appointment to see if they can find anything wrong or a maybe needs a SW update.

Are you actually having an issue?

Was there a fault or lack of performance in a system somewhere which led to the perceived need to check LVB SoC or did you check the LVB voltage and then believe you have an issue from the SoC information you obtained?

Doesn’t those charge percentages show that the car’s performing within specification.

From technical papers I have read, the design is such that when LVB SoC reaches 40% charging via DC/DC converter starts within 48hrs, if SoC drops to 30% LVB charging starts immediately.

LVB charges whether car is On, Off, HVB is on charge or not. Only exception is that if HVB SoC is under something like 3% as far as I recall LVB will not charge.

I’m nearly nearly 3years and 82,500 miles up and never once felt a need to look at LVB SoC though when I check HVB SoH I have taken a peek at LVB SoC only because of various posts and never once found 100% LVB charge which I don’t see as a problem, fault or other issue while everything is working just fine.

I always think understand and don’t misuse information, if it ain’t broke don’t try & fix it and don’t f**k about with something which works correctly to make it broke??‍

 

[Shayne]

I was hoping everyone gets the OTA for the 12V BMS and it stops all this talk about the 12V battery.

Put a 12V power supply from a PC in there and it will boot without the silver dollar (12V) CMOS battery. Set your clock and put it in drive. Not like a 12V power supply is something new to boot and run circuit boards.

 

[zvez]

Are you actually having an issue?

Was there a fault or lack of performance in a system somewhere which led to the perceived need to check LVB SoC or did you check the LVB voltage and then believe you have an issue from the SoC information you obtained?

Doesn’t those charge percentages show that the car’s performing within specification.

From technical papers I have read, the design is such that when LVB SoC reaches 40% charging via DC/DC converter starts within 48hrs, if SoC drops to 30% LVB charging starts immediately.

LVB charges whether car is On, Off, HVB is on charge or not. Only exception is that if HVB SoC is under something like 3% as far as I recall LVB will not charge.

I’m nearly nearly 3years and 82,500 miles up and never once felt a need to look at LVB SoC though when I check HVB SoH I have taken a peek at LVB SoC only because of various posts and never once found 100% LVB charge which I don’t see as a problem, fault or other issue while everything is working just fine.

I always think understand and don’t misuse information, if it ain’t broke don’t try & fix it and don’t f**k about with something which works correctly to make it broke??‍

interesting, but yet when I was in discussions with BEV team about a non related charging issue I had, they did state the 12v needed to be 80% or better for OTAs (I don't know if all or not). I just check my 12v more out of curiousity but my state of charge on the 12v has never fallen below 81% and typically stays in the 85-95% range. This is a 23.5 GT. I do believe I've read that they did change the topping up parameters of the 12v on 23 model cars.

 

[Teslaeata]

Just run a check and with vehicle On LVB charges, after a period of rest and vehicle Off is at 11.9V 64% not charging so all is fine.

my experience is that modules cease to communicate and operate properly if V drops to 9V or 8V depending on vehicle so 40% or even 30% shouldn’t be an issue so long as charge system’s working which I think OP found it was.

 

[Teslaeata]

interesting, but yet when I was in discussions with BEV team about a non related charging issue I had, they did state the 12v needed to be 80% or better for OTAs (I don't know if all or not). I just check my 12v more out of curiousity but my state of charge on the 12v has never fallen below 81% and typically stays in the 85-95% range. This is a 23.5 GT. I do believe I've read that they did change the topping up parameters of the 12v on 23 model cars.

V interesting about the new top up parameter. Thnx.

 

[zvez]

Just run a check and with vehicle On LVB charges, after a period of rest and vehicle Off is at 11.9V 64% not charging so all is fine.

my experience is that modules cease to communicate and operate properly if V drops to 9V or 8V depending on vehicle so 40% or even 30% shouldn’t be an issue so long as charge system’s working which I think OP found it was.

but then why the requirement for 80% for at least some OTAs? I understand it pertains to longer duration OTAs. The other thing I wonder tho is why mine literally never has been below 80% in six months of ownership. (a 23.5). Keeping in mind that most of my driving is the least efficient, ie only very short duration trips ( may drive a total of a 100 miles in a week) and charge once or twice a week?

 

[Teslaeata]

I wouldn’t try & overthink it, if all works it’s fine, don’t let it spoil your enjoyment of this amazing car. Mine updates fine and I don’t worry about 12V SoC

 

[lesz]

23 extended range AWD Mach E, had anyone else run I to this issue below.

Since the 12 v battery update I am having 12v battery drain issues. 2weeks ago vehicle parked at train station (3 days) drops to 39 percent. Noticed a few more times 12v hits mid 40 percent while on charger, HVB is swt to charge to 90 percent. Gomout for a 45 mi drive today and charges to about 60 percent. I have double checked nothing is plugged into a USB port and nothing is plugged in on the 12v outlet under the arm rest.

I did get the OBD Max + for the port paired with car scanner. 12v battery running at 15.1 v. Next step is making a dealership appointment to see if they can find anything wrong or a maybe needs a SW update.

I have similar experience with my ‘22 GTPE. I became interested in the 12V when I had an OTA that would not update. Ford informed me that the SOC for the 12V was insufficient for that OTA. Like you, I don’t drive it often or long distances. I seem to have better luck increasing the SOC for the 12V when I run the car running in the garage with everything off. Driving the car for 45 minutes or so at 65 miles an hour does not seem to help as much as just leaving it in the garage running. Also, Ford has repeatedly assured me that keeping the car plugged into the wall charger would keep the 12V battery charged. My experience is that is only true as long as the car is actually charging. Once I reach my target, 90%, it no longer seems to increase the charge for the 12V. I know some of the more knowledgeable contributors. on this forum will question the logic of my experience given the cars intended functionality. But, that is what I’ve observed. BTW, my Ford dealer did pick up my car and tested the 12V battery and all seems to be fine.

 

[smunro622]

Thank you everyone who posted only reason for the ask is I have again received that my battery is 35 percent and I have a drain and service is required nothing is plugged in to a USB port or 12v port in the arm rest. Last time was in parking lot in a train station, this time parked in the driveway and temps in the 40/50's...making appt to see if it is a draw, software/BCM issue or bad battery. No issues on the HVB this is the 12v LVB. Driving it today for an hour made the 12v battery hit 60 percent

Sponsored