12V Battery - Something has to be done!

Mach-Lee

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Hmm. I did not do this procedure after swapping the 12v battery a few weeks ago, I wonder if that explains the "charging system, service soon" message that I am now seeing in the IPC @Mach-Lee ?
Yes the BMS reset procedure MUST be done after a battery change or you will continue to have problems. Charge battery first for best results (does not have to be 100%, just mostly charged). Please go back and do the reset.
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mkhuffman

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I am getting my battery ready for installation this weekend. It took about 3 hours to get fully charged, but I am going to leave it connected until I am ready to install it. And then I will immediately do the BMS reset.

Ford Mustang Mach-E 12V Battery - Something has to be done! 1000011829
 

iam-s-Hon

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This discussion would go away if Ford went back to the old software that had the SOC of the 12V battery on the first page of the website and the large battery SOC on a second page.
I think MME owners are responsible for this change because they complained that they couldn't work the software.
I decided that since I own a 2021 MME to get a moniter ($13) to plug into the 12V receptacle. Be careful if you buy one of these. Don't leave it plugged in, some have reported fires due to the moniter. Treat it as a meter and then pull it out.
Band-aid. Not a very useful solution IMO

i mean, I have to log in every day or so to the website to check?

App, maybe. But I rarely take my laptop when I’m away for the weekend and logging on via phone? That‘s so 2010.
 

azerik

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My old Focus EV will actually drain the 12v if I need to charge it from near Zero to 100%. Not entirely sure why this happens but it's happened twice in 3 months under nearly the same variables. Car had less than 5% HVB SOC (and less than 5 miles one time), plugged in over night, started the next day and the 'battery' of warnings along with something like Check 12volt battery warning. Metered it 5 minutes later and it read 10.9volts. BUT if you leave the Focus running it it slam charges that lead acid battery(at 14.4 volts) and when you power off after like 2 hours it's over 12.5 volts (and sounds like it's boiling!). From what i'm seeing my car leaves the 12v. on while charging on L2. Thank goodness my MME doesn't do that because it takes longer than the 7 hours the Focus takes from <5% to 80%.
 

Fat Mach

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You probably got the timing wrong. Try again.

The battery should be in a fully charged state (or nearly so) before resetting the BMS. I recommend an overnight charge of the new battery before installation. The car's reading of SoC before a reset does not matter, proceed with the reset regardless. (For example, if you know the battery is fully charged but 12V SoC says 70%, you can reset it anyway.) An accurate SoC will be determined in the next six hours of idle time following a reset.

Ford BMS Reset Procedure:
  1. Press the START button without pressing the brake to engage ACCESSORY mode. NOTE: Complete steps 2 and 3 in the next 10 seconds.
  2. Flash and release the high beams with the stalk 5x
  3. Press and release the brake pedal 3x
  4. Battery icon on instrument cluster should flash 3x
  5. Turn OFF the car and open the driver's door
If the battery icon does not flash, you may have completed steps 2 and 3 too fast or slow. Try again with a one-second cadence.
Much appreciated! I think I didn't have it all completed in less than 10 seconds previously. All is well now!
 


doogie63

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I'm surprised someone hasn't made a new panels with a door for easier access to the battery. At least for jumping the battery. Ford should create a new mold for a panel to replace the stupid design they have now. EV have less part then an ICE car but they couldn't figure out and easy access to the battery? I rather have less room in drunk but easy access to my battery.
 

HuntingPudel

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I'm surprised someone hasn't made a new panels with a door for easier access to the battery. At least for jumping the battery. Ford should create a new mold for a panel to replace the stupid design they have now. EV have less part then an ICE car but they couldn't figure out and easy access to the battery? I rather have less room in drunk but easy access to my battery.
You mean like this? ??

Ford Mustang Mach-E 12V Battery - Something has to be done! IMG_5082
Ford Mustang Mach-E 12V Battery - Something has to be done! IMG_5083.JPG
 

Mosworthy

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I'm surprised someone hasn't made a new panels with a door for easier access to the battery. At least for jumping the battery. Ford should create a new mold for a panel to replace the stupid design they have now. EV have less part then an ICE car but they couldn't figure out and easy access to the battery? I rather have less room in drunk but easy access to my battery.
Like this?
Ford Mustang Mach-E 12V Battery - Something has to be done! 1000014534
 

Mosworthy

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Why
Still no way to easily pull the battery out, lol
Plus it needs a lock on the door handle, lol
Why do you need to pull the battery?

4.5 years, I've never wished for a manual lock.

Heck, I even got rid of the silly wings in the front doors
 

Sikkun

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I drilled holes….but only because I do my own updates with FDRS so I’m plugging the battery in more than normal.

But for the couple times you might jump the vehicles over ownership…..people have really oversold how “hard” taking the beauty panels off is.
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