Dead MME !

[SnBGC]

So unfortunate but so much for those people that said this situation has been resolved. I just don’t understand the 12V battery issues. I am no engineer but with All the testing they should have done, this never should have happened.

good luck and hope they find the problem quickly.

I suspect none of the manufacturers did very much testing that started with "Let's leave the car alone in the cold and not stimulate it at all for days or weeks at a time."

Check any EV forum that you want. They all contain 12v battery woes. I think many have under estimated the need for robust LVB system.

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[Mach1E]

With all the tech in these cars, shouldn’t 12v battery voltage be super easy to read and alert you if it needs charging waaaaay before it goes completely dead?

 

[SnBGC]

With all the tech in these cars, shouldn’t 12v battery voltage be super easy to read and alert you if it needs charging waaaaay before it goes completely dead?

I think Ford was counting on folks driving the car more often.

 

[Mach1E]

I think Ford was counting on folks driving the car more often.

Sitting for 5 days shouldn’t kill a 12v.

Hell, sitting for 5 weeks shouldn’t kill it. Especially on a new car with a new battery.

On my ‘69 Mustang, I go weeks without driving it sometimes. 12v still starts right up. Only time I had an issue was either the battery was 5+ years old or I had something drawing power. Once it was a door light switch, another time it was the brake light switch.

 

[SnBGC]

Sitting for 5 days shouldn’t kill a 12v.

Hell, sitting for 5 weeks shouldn’t kill it. Especially on a new car with a new battery.

On my ‘69 Mustang, I go weeks without driving it sometimes. 12v still starts right up. Only time I had an issue was either the battery was 5+ years old or I had something drawing power. Once it was a door light switch, another time it was the brake light switch.

Agreed.

 

[Craigeddy111]

Agreed.

Truly bizarre, and a bit disturbing. As someone who works from home currently...possibly indefinitely, I don't always drive anymore through my work week. Sometimes just the weekends. My car has never given an issue.

 

[jlauro]

A couple of general recommendations for health of your 12v and 400v batteries...

Generally do not leave your car plugged in for more than a day at a time. Heard it's been fixed with an update, but at some builds the 12V battery will not charge when the vehicle is plugged in. In other words, leaving it plugged in at 100% isn't good for it.

Have your car auto-start at least once a week if you don't drive it at least a couple of times a week. That should keep your 12v battery topped off.

If you do want to leave your car plugged in all the time, but will not be driving it for a long time (a month or longer), set it to only charge to 50%, and set TOD charging so it doesn't keep the 400V battery engaged 24x7.

The 100% indication is only for the 400V battery, and unfortunately it never displays the state/health of the 12v battery (it is available on an obd-ii reader if you connect one).

Still doesn't explain why your 12V would of died assuming it was driven the previous day... when was the last time you drove the vehicle prior to charging it to 100% and it going dead?

 

[kennethjk]

Last winter I left a 2014 911 in the garage from late December to mid March - normally I use a trickle charger on it for the winter but forgot to this time. It had the original battery and only 22k miles, so not driven a lot to begin with.

when I got home I thought for sure that it wouldn’t start. First try, it started. I realize it doesn’t have all the techno stuff the MME has but leaving a car in the garage for a few days, it should Start, no excuses.

 

[SnBGC]

Last winter I left a 2014 911 in the garage from late December to mid March - normally I use a trickle charger on it for the winter but forgot to this time. It had the original battery and only 22k miles, so not driven a lot to begin with.

when I got home I thought for sure that it wouldn’t start. First try, it started. I realize it doesn’t have all the techno stuff the MME has but leaving a car in the garage for a few days, it should Start, no excuses.

I don't know what it is like to live where it gets really cold but we have an office in Greenfield Wisconsin. Apparently it gets so cold that the office staff have to start their cars during their lunch hour because if they don't, then the car might not start when they get off work at 5 pm. Must be brutal there during the dead of winter.

 

[FCCinAZ]

With my extended range premium, I used to get the message that the 12V battery was charging through Ford Pass while on the charger. I don’t get that message anymore with my GT. Software update or it no longer charges the 12v while on the charger?

 

[kennethjk]

I don't know what it is like to live where it gets really cold but we have an office in Greenfield Wisconsin. Apparently it gets so cold that the office staff have to start their cars during their lunch hour because if they don't, then the car might not start when they get off work at 5 pm. Must be brutal there during the dead of winter.

I live a little bit north of NYC and at most we have a few days In a row of weather around zero, sometimes a pipe freezes, but never had a battery problem if a car was left out for a few days.

but I have never experienced the cold that northern NYers or others in Wisconsin face on a consistent basis. I also don’t go ice fishing like they do.

I enjoy the warm weather in Florida for the winter and spring thru fall in NY For some golf.

 

[Kamuelaflyer]

I will be picking mine car up soon and it was sitting for months before it was shipped. do you know if tthe dealer can check the 12volt battery before I take ownership?

They have a predelivery checklist. I’d have to dig deep into darkest recesses of this forum to see if we ever ousted it. But I’d simply ask them to check the 12v battery status and condition. Who cares if they think you’re looney? They’ll still want your money and will do it. And odds are it done by them anyway.

Its cold this time of the year in the Northern Hemisphere. That should make any flaws in the 12v battery more obvious.

 

[kennethjk]

They have a predelivery checklist. I’d have to dig deep into darkest recesses of this forum to see if we ever ousted it. But I’d simply ask them to check the 12v battery status and condition. Who cares if they think you’re looney? They’ll still want your money and will do it. And odds are it done by them anyway.

Its cold this time of the year in the Northern Hemisphere. That should make any flaws in the 12v battery more obvious.

They may have a checklist but if the car starts don’t expect them to actually check voltage on battery, be safe and make sure they check it.

 

[Neilthepilot]

Sitting for 5 days shouldn’t kill a 12v.

Hell, sitting for 5 weeks shouldn’t kill it. Especially on a new car with a new battery.

On my ‘69 Mustang, I go weeks without driving it sometimes. 12v still starts right up. Only time I had an issue was either the battery was 5+ years old or I had something drawing power. Once it was a door light switch, another time it was the brake light switch.

The only thing your '69 has on while it is sitting is a simple clock. Even modern ICE vehicles have problems sitting do to items using the battery.

 

[Don_23805]

Does anyone recall the exact circumstances in which the 12 volt battery wasn't being charged while the charging cable was plugged in? Something about a software issue that would disable the 12V charger when you were charging the HV battery?
I recall a newbie asking about that recently and the answer was that the issue had been resolved with an early update.
I've had the MME for about a month and didn't always plug it in at home. Never had a problem. Then left it plugged in over a week of Xmas holiday without use and now find the batt dead. It says my software is up to date (as one would hope for a new car). Maybe not.
Don

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