12v battery issue questions from a new owner

[DugthePug Dad]

I don't drive much because I'm retired.

This being said I have read about the 12V battery issues.

How concerned should I be about that battery failing?

Should I keep my Mach E plugged in after reaching my desired charge level?

Any suggestions or recommendations are appreciated.

Like I said I'm a rookie, 755 mile rookie...

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[RickMachE]

Ideally, your car is always plugged in while at home. Keep it charged to 90%. Come home, plug in. 12v will be fine.

 

[PedroDaGr8]

The LVB only charges when either the HVB is charging OR when the car is operating and the battery management system is charging it. From my understanding, once the HVB is fully charged, the LVB stops charging as well.

 

[ChasingCoral]

Most of the problems with maintaining the 12v battery have been pretty well solved. After an incident the first month (February 2021), I haven't done anything to baby the 12v battery in 2-1/2 years of driving ours.

 

[Mach-Lee]

Should I keep my Mach E plugged in after reaching my desired charge level?

No, staying plugged in doesn't keep the 12V battery charged.

You don't need to do anything different unless you are getting 12V battery error messages or failed OTAs. Most people it will be fine.

 

[HuntingPudel]

Just make sure that you don’t have any hardware or software installed that would constantly “ping” the 12V battery. Some power companies have you connect your FordPass account to their monitoring system and they keep your car awake, draining your 12V. Some accessories constantly drain the 12V. If you have no aftermarket add-in’s like those, you should be fine. The early cars didn’t charge the 12V reliably when the car was asleep, leading to the early rash of accidents 12V battery failures. There have been a few software updates to the cars since then that address this. ??

 

[Teslaeata]

I don't drive much because I'm retired.

This being said I have read about the 12V battery issues.

How concerned should I be about that battery failing?

Should I keep my Mach E plugged in after reaching my desired charge level?

Any suggestions or recommendations are appreciated.

Like I said I'm a rookie, 755 mile rookie...

Whether plugged in or not, whether “on” or not, if the 12v needs charging the DC/DC will charge the LV 12v battery.

My advice: Just don’t worry & don’t overthink things.

Enjoy the ‘Stang and the EV experience.

I don’t even think of it as an EV or anything different anymore having done 63,500 miles in 26months, it’s just “the car” to me……..and what a car?

 

[Teslaeata]

No, staying plugged in doesn't keep the 12V battery charged.

You don't need to do anything different unless you are getting 12V battery error messages or failed OTAs. Most people it will be fine.

THIS!

Well done, Mach-Lee, good, sound advice for those needing confidence in life with a ‘Stang.

 

[RickMachE]

No, staying plugged in doesn't keep the 12V battery charged.

You don't need to do anything different unless you are getting 12V battery error messages or failed OTAs. Most people it will be fine.

Just to clarify, while staying plugged in doesn't keep the 12v battery charged, there is no reason to unplug after charging unless you're ready to use the car, or you need to move it out of reach of the cable. In extremely hot, or cold weather, the car can utilize house current to cool, or warm, the battery if plugged in, which it won't do if unplugged.

For us, it's simple. Come home, plug in. Charges to 90% during off-peak hours. Unplug when going out. Every morning is a "full" (90%) tank.

 

[Auto Motive]

No, staying plugged in doesn't keep the 12V battery charged.

You don't need to do anything different unless you are getting 12V battery error messages or failed OTAs. Most people it will be fine.

Dealer needed to do updates when I had a 12v battery fault along with a susp fault. Dearler only update 4 hours to complete. Its been 2 months all is good.

 

[Jtbuster]

Ideally, your car is always plugged in while at home. Keep it charged to 90%. Come home, plug in. 12v will be fine.

Not true

 

[Maquis]

Not true

 

[AZBill]

Today my wife went to drive the MME and it was completely dead, the driver door would open but nothing else worked. I opened the hood and had already made access holes for the battery jump points. It was reading 3v. Connecting a charger got things going, but it posted a message on the screen about turned off to conserve power.

I pulled the back panel off in the frunk and found the positive battery connector was lifted off the battery and making intermittent contact. Pushed it back down and tried to tightened the connection. That connector will not tighten, it appears to be broken. Going over a bump probably caused it it slide off.

Headed to the dealer this week. After at least pushing this connector back down, the car works.

Also, over the last two weeks we had gotten power train errors and a few other error messages as well. All likely due to this bad connection.

 

[Mach-Lee]

Today my wife went to drive the MME and it was completely dead, the driver door would open but nothing else worked. I opened the hood and had already made access holes for the battery jump points. It was reading 3v. Connecting a charger got things going, but it posted a message on the screen about turned off to conserve power.

I pulled the back panel off in the frunk and found the positive battery connector was lifted off the battery and making intermittent contact. Pushed it back down and tried to tightened the connection. That connector will not tighten, it appears to be broken. Going over a bump probably caused it it slide off.

Headed to the dealer this week. After at least pushing this connector back down, the car works.

Also, over the last two weeks we had gotten power train errors and a few other error messages as well. All likely due to this bad connection.

So the positive terminal clamping screw broke? Who was the last one to tighten it?

Your wife is very lucky that didn't come loose while she was driving because that could have been an instant brick in motion with no power steering or power brakes.

 

[AZBill]

Ford dealer did a repair for me, due to rodent wiring damage, about 6 months ago. I am sure they had the battery disconnected to do that work. What is interesting it that the screw feels pretty firm, but never actually tightens. It is also a very different design than the negative terminal.

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