Winter storage and 12V battery

[CaptainKirk]

Leaving my 2024 Mach e in heated winter storage for a number of months, plugged in and set at 50% as recommended by Ford. I think I’ll take Ford’s advice and disconnect the 12V battery, but I’ve seen some posts about the alternative of using a battery maintainer, or even keeping the 12V connected. Has anyone tried leaving the 12V connected and what was the result when you returned? I’m told that the 12V does get something similar to a trickle charge from the HVB.

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[Sikkun]

At multiple months I would do what the manual suggest for best results.

 

[RickMachE]

Leaving my 2024 Mach e in heated winter storage for a number of months, plugged in and set at 50% as recommended by Ford. I think I’ll take Ford’s advice and disconnect the 12V battery, but I’ve seen some posts about the alternative of using a battery maintainer, or even keeping the 12V connected. Has anyone tried leaving the 12V connected and what was the result when you returned? I’m told that the 12V does get something similar to a trickle charge from the HVB.

You need to reread Ford's recommend, because it is NOT plugged in.

Can't charge if thr 12v is disconnected...

 

[CaptainKirk]

Thanks RickMache. Much appreciated.
I misinterpreted Ford’s statement in “how to prepare my electric vehicle for long term storage” (2024-07-28). I thought that “MAINTAIN the HV battery state of charge at approximately 50%” meant to keep it plugged in.

 

[Doobster6]

So logic would tell me that you should keep the car plugged in, and set it up to charge automatically to keep HVB at 50%. The HVB will then take care of keeping the 12V battery charged as needed. At least that‘s my current understanding of how this car works and so what seems right to me.

 

[RickMachE]

So logic would tell me that you should keep the car plugged in, and set it up to charge automatically to keep HVB at 50%. The HVB will then take care of keeping the 12V battery charged as needed. At least that‘s my current understanding of how this car works and so what seems right to me.

Except that Ford provides specific instructions, and that's not what they say.

 

[Kamuelaflyer]

 

[Doobster6]

Except that Ford provides specific instructions, and that's not what they say.

I totally agree that that isn’t what Ford says, but why is it a bad idea? Can someone provide a response from an engineering perspective that explains why It is?

 

[RickMachE]

I totally agree that that isn’t what Ford says, but why is it a bad idea? Can someone provide a response from an engineering perspective that explains why It is?

1) On some updates, Ford hiccups and the car charges to 100%.

2) While the 12v is supposed to stay charged off the HVB, numerous people have had it die anyway. It only charges when the vehicle charges, so sitting at 50% won't charge the 12v.

3) Should there be a power spike, it is possible the car gets damaged. Can't unplug if you are not the home.

 

[JSW]

I would unplug and use a battery tender (whether you disconnect the 12v or leave it connected).

 

[Doobster6]

1) On some updates, Ford hiccups and the car charges to 100%.

2) While the 12v is supposed to stay charged off the HVB, numerous people have had it die anyway. It only charges when the vehicle charges, so sitting at 50% won't charge the 12v.

3) Should there be a power spike, it is possible the car gets damaged. Can't unplug if you are not the home.

Hmmm…..so the I’ve been misinformed, or simply misunderstood, how the HVB charges the 12V battery. I had read that the HVB will ‘wake up’ as necessary to charge the 12V, even when not plugged in. This was supposedly a software update implemented back in 2023, that helped correct the 12V discharging problem……

 

[RickMachE]

Hmmm…..so the I’ve been misinformed, or simply misunderstood, how the HVB charges the 12V battery. I had read that the HVB will ‘wake up’ as necessary to charge the 12V, even when not plugged in. This was supposedly a software update implemented back in 2023, that helped correct the 12V discharging problem……

Yet a lot of 2023s have gone dead...

 

[SONEWBE]

I have read a lot of conflicting information on this subject. I do know that Ford has said a number of things that turned out to be incorrect, so I take Ford’s advice carefully. In this case, I do agree that the car should not be connected to your EVSE while on extended travel. I’ve had my car default to 100% charge 2 - 3 times after an update. This would not be good if it happens while you are away. In the case of the 12V battery, I connect my battery to a trickle charger and leave it connected to the car so all systems are maintained while away. I know it’s better for the 12V battery and I believe it’s better for the car.

I am more than willing to dis-connect the 12V if someone can provide a good engineering reason for this.

 

[SONEWBE]

So logic would tell me that you should keep the car plugged in, and set it up to charge automatically to keep HVB at 50%. The HVB will then take care of keeping the 12V battery charged as needed. At least that‘s my current understanding of how this car works and so what seems right to me.

Your HVB is likely to change more due to temperature changes than a few months of storage. After my last trip of 3 months, my battery was actually 1% higher when I returned. Probably due to a 10 degree temperature increase in my garage…..just my experience.

 

[Maquis]

I am more than willing to dis-connect the 12V if someone can provide a good engineering reason for this.

Ford says this:

Apparently having modules powered has some effect on the HVB.

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