Do these 12v battery issues exist in the 2025 model?

[joshtb86]

Do the same issues exist in the 2025 models? Dying early etc?

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[Ncasini]

Do the same issues exist in the 2025 models? Dying early etc?

YES
Battery swelling too
Check all connections on the battery. I mean ALL connections.
i found them loose and somewhat oxidized. Check under the BMS on the negative terminal. Mine was not tight and could hear a hissing sound like a loose connection. I cleaned the oxidation off the contact areas and used dielectric grease (silicone) on all the connections and made all the connections tight.
I bought a NAPA battery. ( there are only 2 manufacturers of this battery, one with the waffled sides like Ford, etc or flat sides like the NAPA. Don’t forget to reset the BMS.
And a 5 amp CTEK battery maintainer.

 

[RLXXI]

12v lead acid batteries are a crap shoot in any year vehicle, 3-4 years normally. Some get lucky and go longer, others not so much.

 

[joshtb86]

YES
Battery swelling too
Check all connections on the battery. I mean ALL connections.
i found them loose and somewhat oxidized. Check under the BMS on the negative terminal. Mine was not tight and could hear a hissing sound like a loose connection. I cleaned the oxidation off the contact areas and used dielectric grease (silicone) on all the connections and made all the connections tight.
I bought a NAPA battery. ( there are only 2 manufacturers of this battery, one with the waffled sides like Ford, etc or flat sides like the NAPA. Don’t forget to reset the BMS.
And a 5 amp CTEK battery maintainer.

Battery maintainer like a trickle charger? Are you plugging that into the pro power bed in the frunk? Got a solar one that plugs directly in to the OBD2 port for on the battery itself

 

[El Duderino]

2025 Flash owner here.

No low battery issues except for one after dealer performed recall via software update in my driveway. I think the 12v battery got drawn done further than normal via FDRS updates.

I completed a long Level 2 AC charge at very low rate (2,200 watts) and it charged the 12v backup to full.

I like low rates of level 2 charging when I can get away with it. My Emporia EVSE has adjustable charging from 6 amps up to 48 amps. I can change it in the app from my phone. Very convenient.

Current charge rate (240v * 10a = 2400w. Then some losses in conversion gets approx 2,200 watts shown in Ford Pass app)

 

[RickLightning]

Battery maintainer like a trickle charger? Are you plugging that into the pro power bed in the frunk? Got a solar one that plugs directly in to the OBD2 port for on the battery itself

No, you don't want to use the truck outlets to power a battery maintainer that charges the 12v battery...

If you use a battery maintainer, either connect it to the jump posts, or make sure the negative is south of the BMS connector.

 

[Heliian]

Mine lasted 3 years and 3 very cold winters before I proactively replaced it before leaving the truck parked for a week unplugged at - 25 deg C this year. Bought a new one from ford that has a 3 year warranty. No problems.

cleaned the oxidation off the contact areas and used dielectric grease (silicone) on all the connections and made all the connections tight.

I hope the order was clean, then tighten, then apply the dielectric grease over top.

 

[RickLightning]

Mine lasted 3 years and 3 very cold winters before I proactively replaced it before leaving the truck parked for a week unplugged at - 25 deg C this year. Bought a new one from ford that has a 3 year warranty. No problems.


I hope the order was clean, then tighten, then apply the dielectric grease over top.

Yeah, many improperly use dielectric grease.

 

[joshtb86]

No, you don't want to use the truck outlets to power a battery maintainer that charges the 12v battery...

If you use a battery maintainer, either connect it to the jump posts, or make sure the negative is south of the BMS connector.

Truck outlet to power the charger sorry should have clarified

 

[joshtb86]

Yeah, many improperly use dielectric grease.

What do you mean just put on top?

 

[RickLightning]

Truck outlet to power the charger sorry should have clarified

You don't want to use ProPower to power a device that is used to charge the 12v battery.

What do you mean just put on top?

It is non-conductive. If you coated the battery terminals, then put on the clamps, remove them and clean all the grease off. Apply the clamps and then tighten. Then, apply the dielectric grease if you see it (totally unnecessary).

 

[MountainAlive]

I’m going to jinx myself here but the 12v on my 2023 has been fine. I drive my truck every day though so it rarely sits. And I don’t leave any accessories plugged in when the truck is off except for the FITCAMX dashcam, but that’s connected to the rear view mirror power which shuts down when the truck is off. If your truck sits for several days in sub freezing temperatures then the 12v might go sooner.

 

[Heliian]

What do you mean just put on top?

Dielectric grease is to keep out moisture and prevent conductivity.

A contact enhancer goes on the connections prior to assembly to make it more conductive. Deoxit is probably the most available. Stabilant 22 is another popular contact enhancer but it's incredibly expensive. I use stabilant on aircraft, never had the need on a battery though.

There are various other battery contact cleaners but never used those either. Purple Scotch brite works well enough for me.

 

[djwildstar]

Do the same issues exist in the 2025 models? Dying early etc?

Ford has not significantly changed the 12V battery management.

In general, the lifespan of 12V batteries in EVs is about the same as in gas cars, roughly 3-6 years, mainly depending on your climate: the hotter it is, the quicker 12V AGM batteries will die.

Unlike gas cars, most EVs have electronic locks and latches, which sets up a catch-22: you can't access the vehicle without 12V power, but you can't jump-start the vehicle or replace the 12VB battery until you can access it.

This isn't the case with the Lightning: you can access the vehicle to jump-start it using only the key that's inside the keyfob. That plus a lithium-ion jump box (or another car with jumper cables) is all you need to get going again.

 

[Kansan]

Ford has not significantly changed the 12V battery management.

In general, the lifespan of 12V batteries in EVs is about the same as in gas cars, roughly 3-6 years, mainly depending on your climate: the hotter it is, the quicker 12V AGM batteries will die.

Unlike gas cars, most EVs have electronic locks and latches, which sets up a catch-22: you can't access the vehicle without 12V power, but you can't jump-start the vehicle or replace the 12VB battery until you can access it.

This isn't the case with the Lightning: you can access the vehicle to jump-start it using only the key that's inside the keyfob. That plus a lithium-ion jump box (or another car with jumper cables) is all you need to get going again.

There were updates to the 12v BMS over the past year. Those greatly improved how my 24 Flash manages the 12v battery - it was very evident this winter. I recall getting one or two updates OTA that affected the 12v system but I’m not sure if there were others - I keep my trucks updated with FDRS and you don’t get the nice summary when you update that way.

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