Mach-E Long term storage

[generaltso]

From what searched in the manual, Ford doesn't recommend using a battery maintainer. I did not read every page of the manual at this point. If I get a Mach E, I will be more interested in reading the entire manual.

Oh, you don't have a Mach-E? Did you at least stay at a Holiday Inn Express last night?

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[generaltso]

Other than the MME lacking an engine-driven alternator, maintaining a 12V automotive battery is not EV specific.

It is when there's a BMS, and you intentionally choose to bypass it for no reason. Ford provides a negative post specifically for external 12V power sources. But you probably weren't aware of that since you don't actually own one.

Nobody's arguing about Ford's recommendation to disconnect the 12V battery for long term storage. But if you're going to use a battery charger or maintainer instead, you should use the negative post that Ford provides for that purpose. I'm not sure why you seem to believe so strongly that you shouldn't.

 

[generaltso]

Well, you can get dickish now, but I'd bet I have as much or more experience maintaining 12V automotive batteries than you.

It's a 12V automotive battery. If you are so informed on the MME LVB charging engineering, why does the HVB system not keep the LVB fully charged while in deep sleep mode?

Because it would have to engage the HV contactors to fire up the DC/DC converter, which it can't do while in deep sleep.

I'm done. Good luck with whatever vehicle you're driving.

 

[Mach-Lee]

And it will also be fine connecting both maintainer leads directly to the battery terminals.

No, DO NOT CONNECT A BATTERY CHARGER TO BATTERY NEGATIVE ON A FORD. YOU MUST USE BODY GROUND. Ignoring this will screw up the BMS and you'll have a bunch of issues with modules shutting down.

The 12V battery is not maintained in deep sleep mode and will eventually go dead if left connected, just like in any conventional vehicle. So a maintainer should be used, connected the proper way with a body ground.

Disconnected lead acid batteries should be fully charged before going into storage, and then recharged every 6 months. OP didn't fully charge the battery before and after storage, so he had issues as a result of not doing that.

 

[fpavlo1]

Sorry this post caused such a controversy. I plan to hook a battery. tender on when I leave for Florida even though the Ford manual says to disconnect the 12V battery. I have used tenders on all my vehicles in the past including a 2013 F150 and always hooked them up directly to the battery terminals. They have always worked unless it is a solid state battery. The negative post on the Mach-E is hooked directly to the battery via the ground cable. There would be virtually no difference hooking to the post or the battery terminal.

 

[thekat03]

Sorry this post caused such a controversy. I plan to hook a battery. tender on when I leave for Florida even though the Ford manual says to disconnect the 12V battery. I have used tenders on all my vehicles in the past including a 2013 F150 and always hooked them up directly to the battery terminals. They have always worked unless it is a solid state battery. The negative post on the Mach-E is hooked directly to the battery via the ground cable. There would be virtually no difference hooking to the post or the battery terminal.

Nah, no controversy here. I just read this thread and say, "I am going to do whatever @Mach-Lee says, because he knows his s*** when it comes to everything about the Mach-E batteries." ?

Good luck, and let us know how the car is when you get it back out of storage. Good learning experience for all of us.

 

[generaltso]

The negative post on the Mach-E is hooked directly to the battery via the ground cable. There would be virtually no difference hooking to the post or the battery terminal.

Look at the negative terminal of your battery again, and you'll see a small box attached to it (it's not just a ground cable). That's the BMS sensor that's between the negative terminal and the chassis ground. Your battery will charge fine if you bypass the BMS, but your car won't know that it did. Still not sure why anyone would choose to bypass the BMS when there's a potential downside with no upside. But to each their own.

 

[RickMachE]

Look at the negative terminal of your battery again, and you'll see a small box attached to it (it's not just a ground cable). That's the BMS sensor that's between the negative terminal and the chassis ground. Your battery will charge fine if you bypass the BMS, but your car won't know that it did. Still not sure why anyone would choose to bypass the BMS when there's a potential downside with no upside. But to each their own.

This. ^^^

Horse. Water. Not thirsty.

 

[HuntingPudel]

As someone who has worked on cars for several decades, I have never seen any documentation that encouraged the connection of a jump, charger, or maintainer directly to the battery negative terminal on a 12V negative ground system. Everything I have read (and written) indicates that a good chassis ground should be used for safety reasons, as well as electrical reasons. Maybe I don’t know what I’m talking about since I’m only an electro-mechanical engineer. Or maybe because I’m canine. ?‍?

 

[generaltso]

Here's a pic of the BMS sensor on my '22 Bronco. If someone tries to tell me there is a safety or electrical difference between the spade on the negative terminal and the chassis ground on the fender wall. I'll laugh.

Nobody said there was an electrical difference. If you send power through a chassis ground, the BMS will know about it. If you send power directly to the terminal, the BMS won't know about it. That's all anyone is saying. What the car does with that information completely depends on the specific vehicle. In the case of the MME, it makes a lot of decisions (like when to transfer power from the HVB to the LVB) based on what it thinks the SOC of the LVB is. Why intentionally confuse it?

This is not the same as ICE cars since their 12V batteries are only charged when the alternator is running. The BMS doesn't have to know that the LVB hit 30% SOC because it isn't going to top it off while parked.

 

[generaltso]

The battery maintainer is not charging the battery when the car is being used (i.e. not in storage). If the LVB is fully charged and attached to the maintainer when the MME is put into storage how can the BMS get confused?

Because the car doesn't go into deep sleep mode the second you put it in storage. It could sit for a week or more before that happens. During that time, the car will use power from the LVB and not know that it's being replenished by the maintainer. That means that when the car wakes up, the SOC of the LVB won't match what the car thinks it should be. I'm not the one overthinking it. I'm just telling you how the MME works, which is completely unrelated to your Bronco. Luckily, Ford gave us a negative post specifically for this purpose, so we don't have to even think about it. I'm not sure why you're so dead set against using it (other than the fact you don't actually own the car).

 

[MustangBarry]

Which battery tenders are satisfactory for maintaining during storage? I see dozens on Amazon from $10 to $300. Seems like low output power (and therefore lower cost) would be fine for this purpose,

 

[generaltso]

You are over thinking the operation of the BMS and believing it is "smarter" than it really is.

Dude, at this point you clearly just want to argue. It's great that you know more about the MME than people that have owned it for years. You started by suggesting using the wires in the front bumper to charge the battery, so you're obviously an expert. By all means, do whatever the hell you want with your MME if you ever own one. Until then, have fun with your Bronco. Best of luck.

 

[RickMachE]

This forum has a great Ignore feature.

Don't know why a non-owner needs to be here and spread misinformation.

 

[MustangBarry]

We are leaving town for 22 days and I’m not inclined to attach a battery tender that I have no track record with. If I understand correctly (and that is questionable) the HVB “maintains” a charge on the 12v until the car goes into a sleep mode. If this is true, then wouldn’t leaving the Mach-E connected to my level 2 charger and setting it to charge for a few minutes each day with a maximum charge level of 50% keep the car in the awake state needed to maintain the 12v ?

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