12V Battery FAQ

[Squire330]

Thanks much for your response. Just can’t help wondering why Ford didn’t use the front bumper portal for a jumper connection instead of merely opening the frunk.

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[MTNestr]

Thanks for all the work you have done!! Is there a way to get a PDF of this whole explanation?

 

[MTNestr]

If I were to turn on my Mach-E with a battery tender still attached to the battery will that damage the battery or any other electronics?

 

[Lite2]

Cudos for the writeup for sure!!
New to the ME but not EV's.
All I have been reading of my new (used) car lately is that ford ain't near as good as GM as far as ANY battery management. My old 22 Bolt was VERY good at all battery maintenance (heating/cooling main and charging 12v while plugged in) so I'm shocked at the Mach E for dumming down things that should be there just for self preservation to say the least. All I can get is that they make it like an ICE car, only charges the 12v when the motor's running.... how non!
No physical key to get into said dead car to get to emergency jump pack.... Dumb all around...
Yes, I do really like the Mach E vs my previous Bolt as far as the ride, room and style but now I have to worry more about it's health.

 

[Snakebitten]

All I can get is that they make it like an ICE car, only charges the 12v when the motor's running.... how non!
No physical key to get into said dead car to get to emergency jump pack.... Dumb all around...

Simply not true.
It does indeed charge when the car is on. (motor is running, so to speak)

It also charges when the HVB is being charged.

It's charged when the remote climate control is triggered.

It's charged when the FordPass departure time is scheduled and the EVSE is drawn on to precondition the Mach-E battery and cabin.

And depending on the BMS software version, (from what I understand) it charges the battery if/when the AGM SOC/Voltage gets below some threshold.

But it's true that if the AGM fails, you can possibly be locked out and facing a real inconvenience. But with a modicum of due diligence, it should be something an informed owner would not experience.

 

[Lite2]

Simply not true.
It does indeed charge when the car is on. (motor is running, so to speak)

It also charges when the HVB is being charged.

It's charged when the remote climate control is triggered.

It's charged when the FordPass departure time is scheduled and the EVSE is drawn on to precondition the Mach-E battery and cabin.

And depending on the BMS software version, (from what I understand) it charges the battery if/when the AGM SOC/Voltage gets below some threshold.

But it's true that if the AGM fails, you can possibly be locked out and facing a real inconvenience. But with a modicum of due diligence, it should be something an informed owner would not experience.

But in all those cases the car has to be "on" in some form, not just sitting there plugged in and being maintained like you left it plugged in for months while no one was home.

 

[mkhuffman]

But in all those cases the car has to be "on" in some form, not just sitting there plugged in and being maintained like you left it plugged in for months while no one was home.

No.

The MME will maintain the LVB whether it is on or off. When off, it monitors the SoC and (using the latest software) will recharge the LVB when it drops below 50% SoC. Previously it would do it at 40%. (Mine still does it at 40%, which is most common.)

You can leave it plugged in or unplugged for months and it will be fine. If you plan to leave it for months though, I believe Ford still recommends disconnecting the LVB. Regardless, it should be fine if you don't.

Relax.

 

[Lite2]

Thanks all, makes me feel a little better now. My Bolt would (based on my Emporia charger stats) hit the battery several times at night for I would assume HV battery conditioning and was supposed to keep an eye on the LV battery along the way.
So far so good, miss the physical buttons like going Tesla but I will get used to it.

 

[Just Lurking]

Thanks much for your response. Just can’t help wondering why Ford didn’t use the front bumper portal for a jumper connection instead of merely opening the frunk.

My best guess as to why they did it this way:

Putting a live 12-Volt jump ports in the bumper would open up the potential for abuse (someone could discharge your battery and lock you out of the vehicle, for example.)

Putting in circuitry to prevent abuse and only allow charging of the battery (but not overcharging) would add cost and complexity to an already complex car.

TL;DR: The frunk opening solution was probably considered less risky and less costly to implement.

 

[HuntingPudel]

Thanks much for your response. Just can’t help wondering why Ford didn’t use the front bumper portal for a jumper connection instead of merely opening the frunk.

Safety. Can’t have a live set of 12V connections out where the car is most vulnerable to impact. ??

 

[dimes4slim]

Thanks to this article and all of this forum members' support, I made the attempt to replace my 3.5 year old battery myself. I'm a 73 year old car guy, but technology has left my skills in the dust. I decided not to take the shortcut access to the battery because I really wanted to see what was under all that plastic. With all of the warnings about losing the clips holding the frunk panels in place, I only came up one short, and I started at two short probably due to previous dealer service, since I found one at the bottom under the tub. It took a leisurely 1.5 hours, and (so far) all is well, including resetting the BMS. I got the Motorcraft battery from Rock Auto at the insanely cheap price of $87 plus the $18 refundable core charge and $12 shipping. It was produced in November, so relatively fresh.
Unfortunately, I still have the outstanding BECM update along with another 15 or so according to FDRS (another shout out to volunteers in this group). I don't know what effect that will have, and I don't know if Ford is responsible, or has any interest to do any of these updates, even OTA. Should any of, or all be done if everything seems to be working OK?

 

[miguelmix]

Thanks to this article and all of this forum members' support, I made the attempt to replace my 3.5 year old battery myself. I'm a 73 year old car guy, but technology has left my skills in the dust. I decided not to take the shortcut access to the battery because I really wanted to see what was under all that plastic. With all of the warnings about losing the clips holding the frunk panels in place, I only came up one short, and I started at two short probably due to previous dealer service, since I found one at the bottom under the tub. It took a leisurely 1.5 hours, and (so far) all is well, including resetting the BMS. I got the Motorcraft battery from Rock Auto at the insanely cheap price of $87 plus the $18 refundable core charge and $12 shipping. It was produced in November, so relatively fresh.
Unfortunately, I still have the outstanding BECM update along with another 15 or so according to FDRS (another shout out to volunteers in this group). I don't know what effect that will have, and I don't know if Ford is responsible, or has any interest to do any of these updates, even OTA. Should any of, or all be done if everything seems to be working OK?

Sorry for your issues, i am receiving mine Motorcraft tomorrow, any way to see when the batery was build?

 

[dimes4slim]

Sorry for your issues, i am receiving mine Motorcraft tomorrow, any way to see when the batery was build?

There is a sticker on the side, but also a lightly printed date on the top of the battery.

 

[Lite2]

I got the Motorcraft battery from Rock Auto at the insanely cheap price of $87 plus the $18 refundable core charge and $12 shipping. It was produced in November, so relatively fresh.

What did it cost to return the old battery for core refund?

 

[dimes4slim]

What did it cost to return the old battery for core refund?

I haven't done it yet, but may see if I come out ahead by just getting a credit at Auto Zone or Advance versus the shipping cost. I will follow up next week.

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