Completely DEAD!!

[JohnFoxeSheets]

The 12V battery is only maintained while the high voltage battery is actively charging. Once charging is finished, the car goes to sleep and the 12V battery may drain dead even though it is still plugged in. I’ll have to look later what’s going on, but could be a charge fault or just a bad 12V battery.

I have posted this before in other threads. Below is the charging strategy for the Mach E. The 12V battery will always charge when needed. If repeated charging is required as a result of some external drain, battery damage will occur.

Taken from Ford Special Vehicle Engineering:
While ignition is off, if 12V battery reaches 40% state of charge, then vehicle waits 48 hours , before the DC-DC transfers 300 Watt-hours of energy to recharge the 12V battery. The HV power comes from either HV battery or wall power while on plug. If the 12V battery state of charge reaches 30%, then this HV to LV energy transfer happens immediately with no delay.
Note:
• This system was designed to recharge 12V battery while the vehicle was left parked for many days
either on or off plug or occasional drain from customer usage. The 12V battery will wear out if this energy transfer is completed daily due to aftermarket loads draining the 12V battery down to 40% or lower.
• Vehicle has 35 Amp-hour AGM 12V Battery

Hmm, my understanding is as per what @Richard L. wrote. What you're saying Lee appears to be different...?

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[Mach-Lee]

OP, you need to work on determining why your 12V battery died. Read the first part of my article for ideas: https://www.macheforum.com/site/threads/how-to-recondition-service-your-12v-battery.11069/

Looking at your history from Sept it looks like you've been using a faulty EVSE with an erratic control pilot. That could be triggering a charge fault that drains the 12V battery. You should never get a flashing red ring error on the charge port, if you do sometimes, then you need to fix that issue.

Another cause could be that TBOX CarPlay interface you have. I'd try disconnecting that.

If none of those causes apply, you may just need a new 12V battery. The 12V battery was very low starting on Sunday evening (6th) and has only gotten worse.

Hmm, my understanding is as per what @Richard L. wrote. What you're saying Lee appears to be different...?

It goes to sleep after charging and the BCM checks the 12V periodically. If it dips below 30-40% the car should wake up and recharge it. However this doesn’t always happen if the battery dies quickly between checks or if the car is in an error state.

 

[JohnFoxeSheets]

It goes to sleep after charging and the BCM checks the 12V periodically. If it dips below 30-40% the car should wake up and recharge it. However this doesn’t always happen if the battery dies quickly between checks or if the car is in an error state.

Thank you Lee for the clarification. That makes complete sense.

 

[Neilthepilot]

Silly question but "It was plugged in" but was it charging. Either a blown breaker or charger/car fault.

 

[dtbaker61]

so.... I just jumped to the bottom since it looks like you have not gotten a fix yet. Have you taken it to the Dealership so they can pull codes and get to the bottom of this? a brief read indicates they may need to pull frunk tub, check charge port, connections, charger.

There have been a few, only one I recall, cases where one of the charge cable connections was loose, and given some very strange charge errors. You can't get to it and pull the fuse box without pulling the tub.

 

[RWG]

The potential for a dead LVB has been discussed on this Forum many times in the past. Fortunately we have not experienced this problem with our MachE, but the previous reports of the problem made me a bit nervous. So I took the precaution of getting a LVB monitoring device so I can check battery voltage just in case there was an ongoing charging issue. I deem the current system notification system as somewhat inadequate because when you get the notification on Ford Pass it may be too late or, Ford Pass may not even notify you , because of a host of issues:

• Ford Pass system may be down; there are literally thousands and thousands of Ford vehicles using Ford Pass, not just the MME. High user volumes can lead to problems that impact all users and that can impact system reliability.
• Your Fordpass app may be broken, outdated
• Your Smartphone maybe be broken, compromised.
• You are out of your phone service area.
• You may be driving without your phone
• etc. etc.

I bought a Cigarette Lighter Port voltmeter from NAPA, less than $25 and just plugged it in. ( I did not come up with the idea, someone else posted it on this Forum long ago and I agreed with the suggestion.)

The voltmeter is in plain sight, everytime I get in the car. I just routinely glance at it and have determined that; When the car is setting, in the off mode, voltages are normally about 12.5v or a little higher, when the car is plugged in and/or I am driving, battery voltage is between 12.5 to 14.5v, i.e. which is an indicator of adequate charging. I would surmise that if at anytime voltage is below 12v , there is something wrong and worth investigating.

Most ICE vehicles have a battery voltage meter or charging system fault indicator built into the vehicle dashboard, but the Mach E does not. I wish Ford would include a voltmeter feature in the Sync System on a software future upgrade and some configurable notification software along with some historical LVB low voltage charting/graphs data. This way, the user community can monitor the LVB charging status/performance and take corrective actions before having an unfortunate scenario, like the one MV10858 had. I believe the technical capability is resident in the Sync system, Ford just needs to do it and not trust Ford Pass as a solution because it is notoriously unreliable. I would suggest the reason the automotive manufacturing/design community put battery charging system indicators in ICE vehicles was because of the many potential charging system failure modes and the serious negative user experience risks. In this case, an EV is no different than an ICE vehicle; i.e. if your 12v battery dies, everything stops and with the MME you are locked out of the car because entry depends on the LVB.



Based on my previous ICE automotive charging system experience, it is likely the system stopped charging many hours before total failure and you didn't even know it. Sometimes, when charging system failures occur, the operator could drive for miles and/or hours and notice nothing, until the battery voltage drops to a critical low voltage level and then everything just stops. There should have, could have, been advance notice of the pending battery failure by monitoring battery voltage.

Editorial comment: I find it curious that the MME was designed so you have to find a 12v source to open the Frunk in a dead LVB situation, instead of building in a mechanical Frunk release solution. Consider this: just about every modern ICE vehicle sold on the planet has a key Fob entry system with a mechanical key back up, but Ford built the MME with a failed battery fault system that requires another 12v source to provide technical access. Obviously the design team anticipated potential issues so they built in the "trap door with 12v wires access" but this seems like a unnecessarily complicated solution when all that's needed is to simply open the Frunk to get access to the LVB. I would love to hear the engineering/design rationale, perhaps it was a cost driven decision?

Good luck.

 

[Knight]

This happens more than you think with a lot of EV's. Odds are the 12V battery isn't really dead. Jump start it (if you don't have a portable jump starter get one), start the car. There's a good chance everything resets and is fine after that.

Where do you recommend keeping your portable jump starter? From what I understand, if the 12V is dead, then you cannot open the doors or the frunk.
I have a jumper box, but if I keep it in the car, and I'm away from home and the battery dies, then it would be effectively useless because I would not be able to get into the car to retrieve it.

 

[Mach-Lee]

Editorial comment: I find it curious that the MME was designed so you have to find a 12v source to open the Frunk in a dead LVB situation, instead of building in a mechanical Frunk release solution. Consider this: just about every modern ICE vehicle sold on the planet has a key Fob entry system with a mechanical key back up, but Ford built the MME with a failed battery fault system that requires another 12v source to provide technical access. Obviously the design team anticipated potential issues so they built in the "trap door with 12v wires access" but this seems like a unnecessarily complicated solution when all that's needed is to simply open the Frunk to get access to the LVB. I would love to hear the engineering/design rationale, perhaps it was a cost driven decision?

If the 12V is completely dead you will not be able to open the driver’s door to pull the hood release since there is no manual key cylinder. Hence the 12V leads to open the frunk with external power become necessary. A jump pack inside the vehicle will also do you no good since you won’t be able to access it.

When the battery isn’t dead, you can’t allow unauthorized persons to open the hood. So a simple cable in the wheel well won’t work.

So if you consider those two requirements, the cables in the front become one of few solutions if you have a keyless system.

 

[Mv10858]

so.... I just jumped to the bottom since it looks like you have not gotten a fix yet. Have you taken it to the Dealership so they can pull codes and get to the bottom of this? a brief read indicates they may need to pull frunk tub, check charge port, connections, charger.

There have been a few, only one I recall, cases where one of the charge cable connections was loose, and given some very strange charge errors. You can't get to it and pull the fuse box without pulling the tub.

I have not my local dealership is starting they can’t look at it until December. I’m waiting on a phone call from Ford EV support to help speed up the process. I’m opening I can hear back today.

 

[dtbaker61]

I have not my local dealership is starting they can’t look at it until December. I’m waiting on a phone call from Ford EV support to help speed up the process. I’m opening I can hear back today.

wow, I'd look for a different Dealership.

Short-term, get a $15 cigarette port voltmeter and stick it in the center console port.
https://www.amazon.com/Jebsens-Charger-Battery-Monitor-Voltage/dp/B01N00I4TM/ref=sr_1_11?

When MME is 'off', the voltage should show somewhere between 12.0-12.8 . It is supposed to 'wake up' MME if it hits 12.0, and grab a maintenance charge from big battery if needed, even when sleeping.

If you ever see less than 12.0, or you do not see the LVB jump up to 14-15 volts when MME is 'on', then you have a problem that needs to get to a Dealership asap.

 

[Mv10858]

wow, I'd look for a different Dealership.

Short-term, get a $15 cigarette port voltmeter and stick it in the center console port.
https://www.amazon.com/Jebsens-Charger-Battery-Monitor-Voltage/dp/B01N00I4TM/ref=sr_1_11?

When MME is 'off', the voltage should show somewhere between 12.0-12.8 . It is supposed to 'wake up' MME if it hits 12.0, and grab a maintenance charge from big battery if needed, even when sleeping.

If you ever see less than 12.0, or you do not see the LVB jump up to 14-15 volts when MME is 'on', then you have a problem that needs to get to a Dealership asap.

 

[dtbaker61]

referring to your info image...

so this doesn't show any problems.....
LVB is sitting at 14.7 because your MME is 'on' - fine
calculated SOC of 71% and average of 80% - fine

it's when MME is 'off' that you have to keep an eye on. You can only do that with a voltmeter without waking up the car. get a voltmeter, stick it in the center console port, leave the armrest and console slider open so you can see the voltmeter from outside the car without opening the door..... check the 12v system voltage in the morning, it should never be less than 12.1

 

[generaltso]

it's when MME is 'off' that you have to keep an eye on. You can only do that with a voltmeter without waking up the car. get a voltmeter, stick it in the center console port, leave the armrest and console slider open so you can see the voltmeter from outside the car without opening the door..... check the 12v system voltage in the morning, it should never be less than 12.1

But the cigarette lighter port doesn't stay powered for long after the car is turned off.

 

[dtbaker61]

But the cigarette lighter port doesn't stay powered for long after the car is turned off.

oh, that's right, that's why I left the hood up and checked battery voltage directly when I was worried about it.

so.... if the OP does not have the access holes cut for direct measure after a night's sleep, the next easiest way would be to get in the car, hit the start button WITHOUT foot on brake to see what the 12v power is at before turning the MME 'on' all the way, it should be something between 12.0-12.4, and then turn MME 'on' fully to make sure it jumps up to 14+ volts.

The 'resting' voltage of the LVB is probably right around 12.4-12.6 if measured directly, but may get 'pulled down' to about 12.2 if you get in and turn on acc power because the welcome lights and such are consuming 12v energy direct from the tiny LVB until you turn the MME fully 'on'. The LVB is so small it sags a fair amount with any significant load on it. System is INTENDED to right to 'on' so the LVB rarely has to support any significant loads.

This is by the way, why I usually turn off either BT or FP when my car is in the garage. Walking by 10-20 times and having welcome lights come on/off is strain and drain I don't want to put on the LVB if I don't have to. I REALLY wish there was a 'garage' location that could be set that would turn off walk-away and approach sensing.

 

[generaltso]

This is by the way, why I usually turn off either BT or FP when my car is in the garage. Walking by 10-20 times and having welcome lights come on/off is strain and drain I don't want to put on the LVB if I don't have to. I REALLY wish there was a 'garage' location that could be set that would turn off walk-away and approach sensing.

This still really confuses me. I've seen several people report that this is how their car works, but mine only wakes up the first couple of times I go near it with my phone/fob. After that, it just stays in its standby state until I open a door.

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