12 volt battery success ?

[hammer thumb]

I have read endless posts regarding issues related to the failure or change out of the 12 V battery. Who can share a success story? Has anyone been able to change out the 12v battery in advance of issues and have a seamless replacement without any issues at all? My 2024 lightning flash (16,000 miles) green machine is the best vehicle I have ever driven. I want to keep it that way. Should I have my 12v battery tested? Should I just order a new one and put it in my self. What is the secret to avoiding all of these problems regarding the 12V. (foto: free L3 charging c/o Jackson Hole WY : ) Thanks

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[ZeusDriver]

A good AGM should last for more than 3 years.

But these catastrophic failures (that Ford and other vehicles have) should be avoidable with better battery monitoring. The only significant failure I had in my old Chevy Volt was the 12v battery failing without any warning. I had incorrectly assumed that I would get a maintenance suggestion based upon periodic checks of charging and discharging rates, voltage changes over time, and calendar time. But no... none of that. The battery failed and the car was bricked until I put in a new battery. A simple job, but it entailed getting a Lyft to an auto parts store, etc. Fortunately the weather was OK.

Way back (in the days of kerosene TVs) I built a micro plug-in hybrid with early LFP battery cells. The little car had a lead acid battery charged by a DC-DC converter from the main pack. The system was anything but problematic. Don't know why the manufacturers have a hard time figuring out haw to make AGM battery maintenance systems work well, given the mission critical nature of the LV battery. Perhaps cell-by-cell monitoring of the LV battery would make sense, although there would be leakage possibilities beyond those of a conventional AGM.

 

[Rice_classic]

Success story here.

Buy new bms for $28, charge battery to full, replace bms, do pedal dance thing and voila.

 

[Beetroot]

3yrs at least

 

[proprepper]

A good AGM should last for more than 3 years.

But these catastrophic failures (that Ford and other vehicles have) should be avoidable with better battery monitoring. The only significant failure I had in my old Chevy Volt was the 12v battery failing without any warning. I had incorrectly assumed that I would get a maintenance suggestion based upon periodic checks of charging and discharging rates, voltage changes over time, and calendar time. But no... none of that. The battery failed and the car was bricked until I put in a new battery. A simple job, but it entailed getting a Lyft to an auto parts store, etc. Fortunately the weather was OK.

Way back (in the days of kerosene TVs) I built a micro plug-in hybrid with early LFP battery cells. The little car had a lead acid battery charged by a DC-DC converter from the main pack. The system was anything but problematic. Don't know why the manufacturers have a hard time figuring out haw to make AGM battery maintenance systems work well, given the mission critical nature of the LV battery. Perhaps cell-by-cell monitoring of the LV battery would make sense, although there would be leakage possibilities beyond those of a conventional AGM.

Same for me with my 2017 Bolt and Volt. 12V dead without any indications/warnings! Stuck in parking garage at work with Volt. Stuck in mother in-laws driveway with bolt!!

I replace my 22MY at 3 years to avoid same issue.

 

[bmwhitetx]

This forum has 21,000 members. I’ve been on here for 4 years and estimate less than 100 true 12V failures.

So 20,000 unreported success stories. My 22 is still rocking the original.

Buy a jump starter and keep it on your truck if you’re worried. Just like any other vehicle. This guy does great tests. Note you don’t need one that will crank a 6 liter diesel.

 

[mr.Magoo]

Success story here.

Buy new bms for $28, charge battery to full, replace bms, do pedal dance thing and voila.

Altough a 24 like OP has should have the new(er) sensor already.

 

[mr.Magoo]

So 20,000 unreported success stories. My 22 is still rocking the original.

Exactly, I think it's been blown out of proportion a bit. It was more of an issue early on 22/23 but I really don't see much of a problem anymore following the updated BMS and software changes.

Now, AGMs have a lifespan and the deeper the discharge the worse it is, so people who have things connected that constantly draw power are more likely to "wear out" their battery. The tell tale sign of this would be the "accessory drawing power" warning in your Fordpass app.

 

[Heliian]

It's rare for a 12v to just fail without warning.

I assure you there were signs before failure. My battery is getting weak but I'm going to milk it until the spring. Once I decide to buy a new one I'll load test the old one for fun.

 

[Mike G]

Success story here.

Buy new bms for $28, charge battery to full, replace bms, do pedal dance thing and voila.

His '24 Flash should already have the later version of the BMS module.

I would go out and do the BMS Learned Values Reset dance every six months though...you're spot on there....

 

[Mike G]

It's rare for a 12v to just fail without warning.

I assure you there were signs before failure. My battery is getting weak but I'm going to milk it until the spring. Once I decide to buy a new one I'll load test the old one for fun.

There are many posts about this 12V AGM just quitting abruptly with seemingly no warning (there may have been signs, but the owners may not have recognized what was happening meant the battery was going out).

If you're still under warranty, they can test and replace your battery for free before your 3yr warranty runs out. Lots of posts on the MME forum about people doing just that.

 

[RickLightning]

I have been in that garage. Can't imagine going in it, or any parking garage, with a trailer.

Starting at 3 years (actually right before the 3 year / 36,000 mile warranty expires), have the dealership do a load test on the battery. Mine does it for free. Lightning failed, Mach-E passed. Free new battery for one.

On my Mach-E, given the inability to open the vehicle if the 12v is dead, we may replace it at 4 years. Vehicle comes with 5 years of free towing. If we go on a long trip, we will take precautions like never leaving the car unoccupied at a rest stop (we never do anyway), so as to not be stranded at a rest stop. But the only long trip we expect to take in the winter is with the Lightning.

Every now and then, I am slowing the charging to both vehicles to 8 or 12amps, drawing out the session to charge the 12v more.

A month or so ago, I connected both to a Battery Tender, and they signaled they were done in minutes.

I also powered up both to see the SOC. Mach-E, used multiple times a week, was at 85%. Lightning, sitting unused for 3 or so weeks, was at 56%. We then used the truck for errands, figuring it would be charged up.

 

[MountainAlive]

This forum has 21,000 members. I’ve been on here for 4 years and estimate less than 100 true 12V failures.

So 20,000 unreported success stories. My 22 is still rocking the original.

Buy a jump starter and keep it on your truck if you’re worried. Just like any other vehicle. This guy does great tests. Note you don’t need one that will crank a 6 liter diesel.

I’ll probably jinx myself but going on almost 2 years and so far no 12v issues. It does go into power saver mode at the start of winter sometimes but it recovers as designed. I do appreciate all the posts here though about what could go wrong and how to fix it. So I at least feel prepared when/if it does happen. I carry a portable battery powered jumper in the frunk just in case.

 

[TaxmanHog]

I waited until just past my 3 year B-T-B expired last August to evaluate and decided to replace my 12v LVB.

The Advanced Auto sales dude tested it, the results indicated it was still serviceable but I decided to err on the side of caution and replaced it with another H3 battery (Diehard)

Install of the new battery went fine in the store parking lot, no issues since the change.

 

[ridgebackpilot]

I just take my Ford EVs to the dealer for a 12-volt battery change when I get the warning message from the Ford app. I’m taking one of my Mach-Es in this week. That battery lasted nearly 4 years and over 90,000 miles.

To me, it’s not worth the aggravation and waste of time to try and change the 12-volt batteries myself and save a few bucks.

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