12V Battery - Something has to be done!

Blue highway

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I dodged the very early 12v battery problems some folks had with their not-even-old 2021s and replaced my Mach E with a Genesis GV60 before my '21 Mach E has any age-relayed 12v issues.

6 months into owning the GV60, I came out to a flat 12v battery and a dead vehicle that was over 90% hv soc when I drove it an hour earlier.

Genesis does provide a physical key - not in the fob but in package that could fit in your wallet. (Some folks gripe about it not being integrated into the fob but with paak and face/fingerprint unlock, separate probably makes sense.)

The battery cover can be opened and moved out of the way by hand without removing any fasteners. (Although the manual instructs you to remove one plastic pop faster. I couldn't figure that out but I did "discover" the rotate trick.)

So I guess Genesis did the mitigation part better....but why are EVs having these no-warning 12v battery issues?

There are no DTCs, no messages....

After the first episode, I bought a Bluetooth battery monitor.

The vehicle was even plugged in when this happened!

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EVs have these issues because the battery is used differently than in an ICE car... and because of this, they are much smaller. The "warning" that ICE cars give you is often noticeable slower cranking... although you don't always notice the loss of capacity before it is unable to crank the car... my Cadillac did that... there can be a "warning". In an EV, you need just enough capacity to light up the computers and fire the HV relays... when there is not enough current capacity to do this, the car goes from perfect to complete fail all at once.

The real warning that the battery gives you is a calendar. Replace the 12v battery at 3 years and save the aggravation of having to do it when the car doesn't start.
 

Coffs

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FORD, listen upā€¦ā€¦ā€¦.I love all the new improvements planned for 2025; cooled seats, heat pump, more center console space. Etc. But what I continually read in these forums is the overall nightmare that is the MMEā€™s 12V implementation. Everyone lives in fear of the ā€˜somewhere-around-three-yearā€™ surprise binary failure, which apparently occurs without notice. Even if covered under warranty, your customers shouldnā€™t be inconvenienced by a total and instant shut down of the entire car, and then the Byzantine means by which it must be corrected by the owner, or towed away back to a Ford dealer. The whole thing in place now for 4 (or is it 5?) model years looks like a last minute Rube-Goldberg solution to an overlooked problem!
Here are some suggestions:

- Change battery chemistry and/or construction to something that doesnā€™t just go from a ā€˜1ā€™ to a ā€˜0ā€™ with no advance warning. Also, these batteries ought to enjoy a 5-7 year lifespan instead of 3 years, just like ā€˜old fashionedā€™ lead-acid batteries currently do.
- Provide the means of gaging/viewing its SOC if thatā€™s still necessary after you make some changes. Lead acid batteries in ICE cars usually warn us with slow engine cranking for example, giving us (usually) months worth of heads-up.
- Change the logic by which the HVB wakes up and recharges the LVB. Maybe this is already in place with recent OTA updates?
- Provide a mechanical override cable (like those often found in trunks) that will allow the front hood to be opened without having to ā€˜jumperā€™ it open through the front portal. I mean, who carries a 12V supply in their back pocket (because you canā€™t keep it in a car that canā€™t be accessed absent 12V power).
- Provide a snap-down lift-up panel under the hood so that itā€™s easy to access and/or remove the battery without having to dis-assemble 2/3rds of the other plastic panels.

Maybe all this has been suggested already throughout the MMEā€™s first years. If so, why arenā€™t we hearing about specific changes to address the issue? Iā€™ll shut up when I see some changes that actually do!

BTWā€¦..otherwise I LOVE my MME, which currently is only 5 months old and has only 2,300 miles. Itā€™s been problem free and a total joy to own! Iā€™ll want to stay with it when my lease is up in 2027, but stupid issues like this one will give me pauseā€¦..
how about an actual key to unlock the doors, dead battery no problem, use key, open doors, pop frunk, charge/change battery. Simple ages old solution to a 2021 onwards problem.
 

devmach-e

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EVs have these issues because the battery is used differently than in an ICE car... and because of this, they are much smaller.
It isn't just EVs that have this issue. Hybrids have the same issue. But at least in my Highlander Hybrid, I can get into the car with a physical key and have jump points in the engine bay that I can hookup a jump pack to. The actual battery is in the back under the trunk floor. I've had to change it once in the 9 years we've owned it. But I have had to jump start it multiple times, mostly due to sitting in the driveway for weeks at a time not being used. This was particularly needed during Covid. Everytime we'd walk past the car to get into the other car (first a Bolt and then the Mustang), it would wake up and greet us with the welcome lighting in the hopes we'd drive it, only to have its hopes and dreams dashed.
 

melissphillips

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I've had my car for well over 3 years and I have never had a 12V battery issue. So it's not universdal.
Neither did I, until the day I did. Now it's sitting like a brick and I'm in an ICE loaner waiting on parts that are not available until after the first of the year, if then.
 

melissphillips

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how about an actual key to unlock the doors, dead battery no problem, use key, open doors, pop frunk, charge/change battery. Simple ages old solution to a 2021 onwards problem.
This and some kind of manual override to put it in neutral so it can move out of a roadway quickly and easily. The existing solution requires the accessory power to be operable, which, if you have a 12v issue, it is not.
 


Blue highway

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It isn't just EVs that have this issue. Hybrids have the same issue. But at least in my Highlander Hybrid, I can get into the car with a physical key and have jump points in the engine bay that I can hookup a jump pack to. The actual battery is in the back under the trunk floor. I've had to change it once in the 9 years we've owned it. But I have had to jump start it multiple times, mostly due to sitting in the driveway for weeks at a time not being used. This was particularly needed during Covid. Everytime we'd walk past the car to get into the other car (first a Bolt and then the Mustang), it would wake up and greet us with the welcome lighting in the hopes we'd drive it, only to have its hopes and dreams dashed.
yeah, my prius 12v died unexpectedly... I think at 7 years. like you state, no warning... but I could at least get into the car.
 

devmach-e

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yeah, my prius 12v died unexpectedly... I think at 7 years. like you state, no warning... but I could at least get into the car.
I don't think I ever had a Prius or Highlander battery die suddenly, i.e car worked fine one day and then was totally dead the next. Mine were always slow deaths where I kept opting to shock the patient into rhythm by putting it on the charger to let it live for another 6 or 7 months. Eventually I would replace the battery.
 

ARK

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I have one of those bluetooth dongles that lets me get vehicle stats from the OBD II port, can I use that to check the 12v battery state of charge? I've previously only used it every several months just to see how the high voltage battery is doing.

If the answer is yes, is there something specific I would be looking for - like below X percentage on the 12v battery, replace it soon. Below Y percentage, it is critical, go straight to the dealership sort of thing?
 

evfinder

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I don't think I ever had a Prius or Highlander battery die suddenly, i.e car worked fine one day and then was totally dead the next. Mine were always slow deaths where I kept opting to shock the patient into rhythm by putting it on the charger to let it live for another 6 or 7 months. Eventually I would replace the battery.
My Prius Plug-in gave me a warning when, after 7 years, it wouldn't start one day. After letting it sit for a short time I tried to start it again and it started OK. I drove it home and the following day the battery was dead. I used the key hidden in the fob to unlock the door, popped the hood, and got a jump start.

The other thing my Plug-in Prius had was that if the fob battery died you could hold it close to the start button and this would allow you to start the car so you wouldn't be stranded. That reminds me I need to get the door codes and the start code for the Mach-e in case this should happen when I am away from home.
 

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how about an actual key to unlock the doors, dead battery no problem, use key, open doors, pop frunk, charge/change battery. Simple ages old solution to a 2021 onwards problem.
That is indeed a good solution, except for those who wish to rely exclusively on PAAK. There is no perfect solution here. But yeah, a physical key would be a great start.
 

HuntingPudel

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I have one of those bluetooth dongles that lets me get vehicle stats from the OBD II port, can I use that to check the 12v battery state of charge? I've previously only used it every several months just to see how the high voltage battery is doing.

If the answer is yes, is there something specific I would be looking for - like below X percentage on the 12v battery, replace it soon. Below Y percentage, it is critical, go straight to the dealership sort of thing?
An OBD-2 interface will only work if the car has power (i.e. it is running or in accessory mode). It will not work if the car is asleep. šŸ¤”šŸ©
 

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That is indeed a good solution, except for those who wish to rely exclusively on PAAK. There is no perfect solution here. But yeah, a physical key would be a great start.
I can't imagine people walk around keyless. I use the PAAK all the time but I have the key as well as I have to unlock other things and since I need other keys why not carry the fob as well. So to me the advantage is not having to take it out of my pocket.
 

ARK

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An OBD-2 interface will only work if the car has power (i.e. it is running or in accessory mode). It will not work if the car is asleep. šŸ¤”šŸ©
I mean before there is a failure, if I can use a car scanner app to take a look at the 12v battery charge level and if I could tell based on that whether mine is still good or if it is in need of replacement.
 

SonicBlue

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I can't imagine people walk around keyless. I use the PAAK all the time but I have the key as well as I have to unlock other things and since I need other keys why not carry the fob as well. So to me the advantage is not having to take it out of my pocket.
I do and itā€™s generally great. My pants last longer, too. But I would take a physical key and use a hideakey under a wheel well.
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