Deep Sleep Mode - 12v battery drained dead [update: Mach-E jump started]

[GoosePond08]

I am curious, is everyone on here that are describing dead battery or powertrain malfunction getting the same calls from Ford as @ChasingCoral is?

Wondering if he is the only one in touch with Ford this much, or do you all seem to have the same response as he has gotten?

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[MachE2021]

I find it surprising that an EV can go dead because of a small 12v battery while there’s a massive electric battery in there. Why can’t they engineer the 12v battery to be automatically recharged from the main battery? This is ridiculous. It never crossed my mind that I could have a 90% charged EV and yet it wouldn’t start because the mini battery under the hood is dead.

 

[tomterky]

I am curious, is everyone on here that are describing dead battery or powertrain malfunction getting the same calls from Ford as @ChasingCoral is?

Wondering if he is the only one in touch with Ford this much, or do you all seem to have the same response as he has gotten?

Not a peep from Ford. I didn't even get the email that my car delivered to my dealership. I was so looking forward to it. Instead, I was the one to call them to tell them my car delivered.

 

[ChasingCoral]

I am curious, is everyone on here that are describing dead battery or powertrain malfunction getting the same calls from Ford as @ChasingCoral is?

Wondering if he is the only one in touch with Ford this much, or do you all seem to have the same response as he has gotten?

I just heard a Ford Engineer is coming out to check @machefan's car:
https://www.macheforum.com/site/threads/rr-fe-my-delivery-dealer-great-mme-issues.3329/post-110312

 

[ChasingCoral]

I find it surprising that an EV can go dead because of a small 12v battery while there’s a massive electric battery in there. Why can’t they engineer the 12v battery to be automatically recharged from the main battery? This is ridiculous. It never crossed my mind that I could have a 90% charged EV and yet it wouldn’t start because the mini battery under the hood is dead.

You've identified what I think is one of two issues going on:
1) A major vampire battery drain in the LVB when the car is off
2) The system maintaining the LVB level off the HVB charge is not keeping the LVB charged.

Remember that there are very important safety reasons to keep the HVB and LVB isolated. You want to make sure that the 400v system keeps the 12v system happy but if there's a problem you don't want to create a hazard by dumping too much power across. There's even a high voltage disconnect identified in the Mach E Rescue Cards for field repairs and emergency workers to make sure the 400v system doesn't cause safety issues.

 

[highland58]

I find it surprising that an EV can go dead because of a small 12v battery while there’s a massive electric battery in there. Why can’t they engineer the 12v battery to be automatically recharged from the main battery? This is ridiculous. It never crossed my mind that I could have a 90% charged EV and yet it wouldn’t start because the mini battery under the hood is dead.

The smaller box below with the orange cable attached to it is the DC to DC converter that converts 400V to 12V to charge the LVB. This is visible when the panel is removed between the frunk and the windshield.

 

[MachE2021]

You've identified what I think is one of two issues going on:
1) A major vampire battery drain in the LVB when the car is off
2) The system maintaining the LVB level off the HVB charge is not keeping the LVB charged.

Remember that there are very important safety reasons to keep the HVB and LVB isolated. You want to make sure that the 400v system keeps the 12v system happy but if there's a problem you don't want to create a hazard by dumping too much power across. There's even a high voltage disconnect identified in the Mach E Rescue Cards for field repairs and emergency workers to make sure the 400v system doesn't cause safety issues.

That makes sense. Thanks!

 

[Heysteve]

I had this exact same issue in Minnesota yesterday. Couldn’t get the car to start on Monday night so I had to leave it at the restaurant I was at, but did get it to start yesterday morning. Got it about halfway home (I only live 3 miles from where the car was at) and it completely died will driving. 4 hours of waiting for Ford Rodside later, and finding out that the tow service had canceled the request without telling me, I finally got somebody to tow the car on my own. It’s back at the dealership getting looked at right now. Very disappointed in Ford Roadside, and hope that they can figure out the issues with the car in the cold.

 

[agoldman]

I had this exact same issue in Minnesota yesterday. Couldn’t get the car to start on Monday night so I had to leave it at the restaurant I was at, but did get it to start yesterday morning. Got it about halfway home (I only live 3 miles from where the car was at) and it completely died will driving. 4 hours of waiting for Ford Rodside later, and finding out that the tow service had canceled the request without telling me, I finally got somebody to tow the car on my own. It’s back at the dealership getting looked at right now. Very disappointed in Ford Roadside, and hope that they can figure out the issues with the car in the cold.

wow... very sorry to hear this happened to you. will be following all this very closely. Was yours one of the ones held up for additional testing?

 

[Heysteve]

wow... very sorry to hear this happened to you. will be following all this very closely. Was yours one of the ones held up for additional testing?

I don’t think that it was held up. My production date was 12/23 and I took delivery of the car on 2/4. Haven’t heard from the dealership yet today, but will post any news I do get.

 

[agoldman]

Yeah, we need a clear answer on this. It's becoming a bit of an epidemic. Bad time of the year for strandings to say the least. And that roadside assist failure is also concerning.

 

[DBC]

I find it surprising that an EV can go dead because of a small 12v battery while there’s a massive electric battery in there. Why can’t they engineer the 12v battery to be automatically recharged from the main battery?

Seems that it wouldn't be a big issue but if you look earlier in this thread you'll find all the videos documenting that 12v battery is a weak point in all BEVs. @ChasingCoral has explained the basic problem. My understanding is that Hyundai claims they have a fix but I don't follow its vehicles enough to know whether this is true. And of course Ford was very very very confident that it had also solved the problem, leading to the conclusion that the announcement of a solution has been greatly exaggerated.

I had this exact same issue in Minnesota yesterday. Couldn’t get the car to start on Monday night so I had to leave it at the restaurant I was at, but did get it to start yesterday morning. Got it about halfway home (I only live 3 miles from where the car was at) and it completely died will driving.

This is concerning because a dead 12v when sitting is completely different than a 12v dying when the car is being driven. Once the car is moving the HVB should be able to charge the 12v without issue.

When you say you couldn't start at the restaurant, could you get into the MME or was the 12v completely dead? By and large the 12v is needed to power the electronics needed to start. Once started the HVB should be able to keep the 12v charged.

 

[Heysteve]

Seems that it wouldn't be a big issue but if you look earlier in this thread you'll find all the videos documenting that 12v battery is a weak point in all BEVs. @ChasingCoral has explained the basic problem. My understanding is that Hyundai claims they have a fix but I don't follow its vehicles enough to know whether this is true. And of course Ford was very very very confident that it had also solved the problem, leading to the conclusion that the announcement of a solution has been greatly exaggerated.

This is concerning because a dead 12v when sitting is completely different than a 12v dying when the car is being driven. Once the car is moving the HVB should be able to charge the 12v without issue.

When you say you couldn't start at the restaurant, could you get into the MME or was the 12v completely dead?

I could get in and "start" it, but it gave me all kinds of alerts and wouldn't let me put it into gear. It was basically running in accessory mode.

 

[zhackwyatt]

Seems that it wouldn't be a big issue but if you look earlier in this thread you'll find all the videos documenting that 12v battery is a weak point in all BEVs. @ChasingCoral has explained the basic problem. My understanding is that Hyundai claims they have a fix but I don't follow its vehicles enough to know whether this is true. And of course Ford was very very very confident that it had also solved the problem, leading to the conclusion that the announcement of a solution has been greatly exaggerated.

This is concerning because a dead 12v when sitting is completely different than a 12v dying when the car is being driven. Once the car is moving the HVB should be able to charge the 12v without issue.

When you say you couldn't start at the restaurant, could you get into the MME or was the 12v completely dead? By and large the 12v is needed to power the electronics needed to start. Once started the HVB should be able to keep the 12v charged.

This is all speculation. The design could be solid, but there with a bug in the implementation. So after they fix this issue, its possible that the 12v problem is "solved". We just don't know the engineering details.

 

[DBC]

I could get in and "start" it, but it gave me all kinds of alerts and wouldn't let me put it into gear. It was basically running in accessory mode.

To address a case like this I carry a little portable charger. You shouldn't need a lot of power to start. You're not cranking an engine you're just powering up a computer. If the terminals were accessible this would be a two minute drill. Since they're not this is going to be a PITA in the MME. Even when the whole 12v battery issues get resolved it wouldn't be a bad idea to carry one of these little guys just in case the 12v goes flat.

But once underway there should never have been an issue. IOW solving the issue ChasingCoral had may not solve your issue. Or maybe the DC-DC converter software is the culprit in both cases, and a software fix will resolve both, which is possible.

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