Mach-E Long term storage

[fpavlo1]

Has anyone had any experience with storing you EV for 5 or six months? The users manual says to disconnect the 12V battery when not using the EV for a long period of time. I did that last November on my 2022 Select model and when I returned in May it would not start and gave a Battery error. The vehicle had to be towed to the dealer and they had to reboot the system. I have a second Mach-E in Florida. It is a premium with extended range. When we left Florida in May I charged the EV to about 67% and left it without disconnection the 12V battery. After talking to my neighbor who has a Tesla Model Y he said that he has never done anything with his EV's. I am wondering what to expect when I get to Florida in November. Will the 12V battery be dead?

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[RickMachE]

The problem with leaving it for 5 or 6 months is that the 12v battery will drain over time even if not connected. It should be disconnected from the car AND put on a battery tender.

If you're not doing that, then you need to put it on a battery tender or charger when you return, and let it return to a full charge before you connect it up to the car.

Car batteries are not meant to sit unused for that kind of time.

As to the one in Florida, it will drain down and go dead.

 

[fpavlo1]

Will pugging the EV to my level 2 charger charge the 12V battery? I thought I saw somewhere that the HV battery would keep the 12V battery charged on the newer models.

 

[21st Century Pony]

Have you considered one of the Noco tenders? I have a Noco plug for the OBDII port and a Noco-"like" battery tender bought at Batteries + Bulbs that mates with the Noco's X-Connect plug. This setup avoids messing with the frunk-area beauty panels and the hard-to-access 12V battery positive (+) post.

I used to have Noco solar panel battery tenders... mostly for my motorcycles. Unfortunately, those panels break easily and are now out of production (I still have a functioning one).

 

[RickMachE]

Will pugging the EV to my level 2 charger charge the 12V battery? I thought I saw somewhere that the HV battery would keep the 12V battery charged on the newer models.

It will not. The EV will charge up, then charge the 12v. Then, it's done. It will sit for most of the 6 months, not charging. Once in a blue moon, it will tap the charger to charge the HVB, and then should charge the 12v, but not regularly.

If it were me, I would put the 12v on a battery tender leaving it connected (negative to body ground) if I was leaving it for 6 months.

 

[fpavlo1]

I have used battery tenders on my classic cars. Can I put a tender on the Mach-E without disconnecting the 12V battery or will that screw something up?

 

[RickMachE]

I have used battery tenders on my classic cars. Can I put a tender on the Mach-E without disconnecting the 12V battery or will that screw something up?

See the post just before you asked this question... Do nothing but hookup the battery tender to the 12V, with the negative to body ground (not the battery).

 

[RickMachE]

No battery tender says to hook up the tender with negative to a body ground. I use tenders year round on my motorcycles and tractor.

For a MME, I'd hook the battery tender leads to the 12V Jumpstart leads behind the bumper cover. But first I'd consult a Ford EV dealership to make sure that is the proper technique.

Two points.

First, you're absolutely wrong. Here's verbatim from the instructions for a Deltran Battery Tender:
For negative-grounded vehicle, connect POSITIVE (RED) clip from battery charger to POSITIVE (POS, P, +) ungrounded post of battery. Connect NEGATIVE (BLACK) clip to vehicle chassis or engine block away from battery. Do not connect clip to carburetor, fuel lines, or sheet-metal body parts. Connect to a heavy gage metal part of the frame or engine block.

Also, this allows the BMS system to function properly.

Second, if you hook it up to the bumper leads, you won't charge your battery, since those leads don't go to the battery. But hey, knock yourself out.

https://www.batterytender.com/site/batterytender/pdf/021-0123 man.pdf

 

[ArthurDOB]

Never heard of a battery tender until I read this thread. Interesting.

 

[RickMachE]

Using the 12V cables behind the bumper cover was a guess on my part based off what the saleswoman told me when I asked how one opens the door if the battery is dead.

Reading the owners manual this evening indicates the 12V jumpers just trigger the frunk to open, which allows access to the 12V battery that is under the frunk trim covers. Then one jumps the Mach E in somewhat conventional fashion.

Then with that understanding, I suggest the OP buy a battery tender and connect the pigtail supplied with it to the 12V battery terminals and leave a battery tender on his MME while it is in storage.

While I no longer use the Deltran brand of battery tender (I did for about 20 years) most tenders are supplied with a pigtail harness with lugs designed to permanently attach to the battery terminals. The language in the Deltran manual is written by lawyers to prevent novices from causing a spark while attaching the alligator clips to the discharged battery when the Deltran charger is plugged into the 120V power source.

I use a tender brand from Granite Digital. If you care, you can download their manual from saveabattery.com. That .pdf document will show battery connection direct to both battery posts either using clips or lugged terminals. There is no risk of hydrogen explosion because (a) a discharged battery (when not being charged) does not create hydrogen gas, and (b) the connection procedure calls for connecting the tender pigtail to the battery first, then plugging the pigtail 2-pin plug into the battery tender, which is a safe distance from the battery.

As stated, that bypasses the BMS and is not recommended, widely known for BMS systems. Harness reaches a ground point just fine. There is no possibility of spark due to the way the tender works. It can be plugged in backwards without harm.

 

[generaltso]

Using the 12V cables behind the bumper cover was a guess on my part based off what the saleswoman told me when I asked how one opens the door if the battery is dead.

If it's a guess, why are you giving it as advice?

The vehicle is in storage, so the function of the vehicle BMS is immaterial to the discussion.

This is all kinds of wrong, and again, if it's a guess why are you giving it as advice? The car keeps track of how much power goes in and out of the LVB, and uses that calculation to estimate its SOC. If you use an external battery charger (or tender) hooked up to chassis ground, the BMS sees the power going into the LVB and adjusts the calculated SOC accordingly. If you connect directly to the battery's negative terminal, you bypass the BMS and the car's calculated SOC of the LVB is completely wrong, which can cause all kinds of other issues. Why not just do it the way that Ford says to instead of guessing?

 

[RickMachE]

Never heard of a battery tender until I read this thread. Interesting.

Most people never need one. I got my first one in 2014 after my 2013 F-150 kept giving me battery saver messages due to not driving enough. Second one for a boat. Third one for the F-150 at in-law's cottage. Never plugged either EV into one yet, but the 2021 (since sold for a 2022) had numerous battery saver issues that the 2022 doesn't seem to have.

I got the message right after my 10,000 mile service where the tech had the headlights on and door open replacing the headlight switch. Cleared after an overnight charge to the car (not the 12v battery) and driving.

 

[generaltso]

Well, according to this thread and Ford's MME owners manual, when the MME sits in a stored state it doesn't charge the LVB, which causes the LVB to discharge. So the BMS apparently is not active when the MME is in storage mode.

I do find the topic interesting as why an EV in extended storage, where the manual says to keep the HVB at 50% SOC, does not keep the 12V battery fully charged.

It will for a while. But the car will eventually go into deep sleep mode and no longer charge the LVB. That's why Ford recommends disconnecting the LVB for long term storage. But if you leave a tender on it (connected to chassis ground), the LVB should be fine without disconnecting it.

 

[generaltso]

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

But why? It's not what Ford recommends and they give you a negative post that's easier to get to specifically for that purpose. I don't understand the reasoning behind intentionally bypassing the BMS when you don't have to and it's not even easier.

 

[thekat03]

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.

Wait... You don't even have a Mach-E, and you're arguing with experienced owners on how to care for it?

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