3-year old 12V battery tests "good" - should I still replace it?

[StrWhtMME]

Hello all,

I've passed the 3-year mark with 26k miles and after hearing some 12V battery horror stories I decided to take my car to the Ford dealer to get a proactive 12V battery replacement. The dealer said they would test it first as a replacement is quite expensive ($500!) and the test came back "good":

Voltage: 14.55V
Measured amperage: 512CCA (battery is rated for 380CCA)

So based on this the "state of health" meter in the report was fully maxed out healthy. To the dealer's credit, they called me and told me to pick up the car, no charge.

So... should I still replace it anyway? Can a battery that tests so well suddenly go bad without warning? Or will the battery normally start to weaken first in the amperage or voltage test before showing symptoms in normal use?

I recently had our battery replaced by Ford Mobile Service. Just cost of battery $135. Done in my garage, no installation chargers, no service fee, and the did a software update. It’s a no- brainer, great service, and you can watch and make sure all is good.

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[Blue PonyE]

With a build date of December 9, 2020, my 12-volt battery lasted a few days shy of five years of ownership. Follow the excellent directions on the threads and replacement is simple. Don't forget to follow the Battery Management System (BMS) once you've reconnected the new battery.

 

[eStang]

With a build date of December 9, 2020, my 12-volt battery lasted a few days shy of five years of ownership. Follow the excellent directions on the threads and replacement is simple. Don't forget to follow the Battery Management System (BMS) once you've reconnected the new battery.

Mine was delivered in Mach 2021. So I'm expecting the original battery to finally give it up soon - but most recent chat with Ford Advisor a few weeks ago said it was still in good health.

 

[Maui]

Batteries seem to follow the path of good health, good health, dead.

 

[sglewiswl]

My single worse experience on the car is the 12v battery.
Dead battery on the Mach-E is a pain in the ass. Getting the frunk open if it goes dead is a pain in the ass. Getting to the battery is a pain in the ass. Getting it in neutral for the guy to tow is a pain in the ass.
Replace it ahead of time and save yourself a couple of days of being mad at how much a pain in the ass a dead 12v battery can be.

 

[IgorKl]

if you like adventure than do not change the battery, if you are conservative and prefer to drive car instead of riding in tow car replace battery soon.

 

[AZBill]

My battery lasted 50 months, and the Ford app told me it was going bad, so I replaced it.

 

[Mach e Mark]

Hello all,

I've passed the 3-year mark with 26k miles and after hearing some 12V battery horror stories I decided to take my car to the Ford dealer to get a proactive 12V battery replacement. The dealer said they would test it first as a replacement is quite expensive ($500!) and the test came back "good":

Voltage: 14.55V
Measured amperage: 512CCA (battery is rated for 380CCA)

So based on this the "state of health" meter in the report was fully maxed out healthy. To the dealer's credit, they called me and told me to pick up the car, no charge.

So... should I still replace it anyway? Can a battery that tests so well suddenly go bad without warning? Or will the battery normally start to weaken first in the amperage or voltage test before showing symptoms in normal use?

Replace the battery, do not pay $500.00. If NASA had a rocket re-entry history of multiple failures on the third voyage but sometimes it made it through 4 or 5, would you fly? (Maybe a little apples and oranges but you're still in the same bowl of fruit!)

Call a couple of dealers or go to Rock Auto and purchase a direct replacement. ( BHAGM-H3 ) Purchase a decent AGM (Absorbed Glass Mat) battery charger. Read Mach-Lee's primer about AGM then put your new battery on the charger for 2 or 3 day's prior to installing it in your car (It's probably been on a warehouse shelf longer than you expect and it needs to desulfate.) Look at a couple of youtube mache battery replacement videos while your desulfating. Re-read Mach Lee's post....

You can change it our yourself and reset the BMS (Battery Management System) if you have a little confidence in your ability. (You bought an electric vehicle so you must!)

Once done, kick back with a cold one and impress your friends with your newfound knowledge.

Go for it.

 

[Roger70]

What exactly are the first signs of a battery ging bad. Is there are list or anything.

My battery is 4 years old can't say I have noticed any mallfunctions or whatever.

So I am curieus what little signs I should be adware of.

 

[Maquis]

What exactly are the first signs of a battery ging bad. Is there are list or anything.

My battery is 4 years old can't say I have noticed any mallfunctions or whatever.

So I am curieus what little signs I should be adware of.

My failed instantly and completely without any warning.

ETA: The failure happened before Ford implemented the warning message in the Ford app. Would I have received a warning message? Who knows?

 

[Teslaeata]

My battery lasted 50 months, and the Ford app told me it was going bad, so I replaced it.

…….which is the way to play it

 

[Eagertrader]

I would. Mine died 1 week before the three year mark without warning. Bricked the car.

 

[EasyPass]

1. My original 2021 12v (4 1/2 years) was checked in February with a multi-function comprehensive test unit and all variables were way above the desired levels.
2. I just finished having it parked at the airport for 2 weeks in frigid temps without any issue. It always responded to a remote Lock-Command during that time.
3. Brand-y new AGMs have been known to fail within 6 months.
4. My dealer quoted $250 for an onsite (my home) replacement batt, but declined to recommend doing so in #1. above based on test results.
5. My wife's 2016 Fusion Energi PHEV original 12v (conventional lead acid) was just replaced in January after nearly 10 years of service.
6. I plan on taking action when the system warning message for the 12v health appears on the ICP.

Life is a gamble and you never know what you're going to get, but facts are what they are.

 

[moncobb]

I replaced mine at 4 years. It tested fine. But its been years since I wanted to risk finding a dead battery. The Motorcraft warranty is 3 years, so that would also be a reasonable interval. You can find opinions everywhere that an AGM should last various lengths of time. "Should last" doesn't mean "will last." So go with your comfort level.

 

[MadMatt]

I want to add that up until 2024 Ford’s BMS was programmed to regularly allow the 12v to drop to the 30-40% SoC. I’m no expert but afaik this was surprising to learn considering that chemistry, lead/agm prefers being kept at a high SoC at all times.

Since 2024 there have been updates to the BMS that now keep the battery above 80%. (When the vehicle is not used for a long time it will drain to 50-60% but should either maintain there or go into a deep sleep to prevent further drain).

All to say, any 3+ year old MachE likely went a long period where the factory 12v spent too much time at low SoC and possibly hurt the overall life of the battery.

I’ve been monitoring my 12v on my late build 2024 and rarely see it under 80%. I also do periodic CCA load tests to establish a baseline in an effort to track its health. I don’t plan on preemptively changing it until I see some signs

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