"Proactive" 12v battery replacement - good idea or overkill?

[nuMach]

data based decision:

battery testers have come a long way ... the old load test style dont take into consideration a lot of factors. This new tech works great. Lets you pick AGM as style, the CCA of the battery, etc.

this will tell you your battery's state of charge and health, 2 different things. battery can be discharged, but still very healthy, eg.

I have the one in the pic ... ~$50 amazon at the time. Done over 30 batteries.
Huge truck style, boats, rv, motorcycles, AGM and lead acid, even 6v golf cart batteries.
Its been dead on every time.

most accurate when run on a disconnected battery ... just one terminal off is OK.

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[nuMach]

And .... topping off your 12v battery

battery tender, charger, recovery tool

Ive used this as a seasonal tender on my motorcycles. battery charger, and have recovered batteries the analyzer above said only had 40% life left.

supports AGM and lead acid

recondition mode overnight - can do it twice, leave for a day ....
can add life to an unhealthy battery or give you time to budget for a new one.
AGMs are $$$

can run a recovery on a good battery to keep it fit once a year eg.

 

[Chuck]

I have never understood this mindset (not limited to EV owners). Why would you replace a perfectly good working battery without load testing it to see if it needs replacement?

I feel the same way. I never go to the dentist until the pain is unbearable!

 

[Tampamike]

I have never understood this mindset (not limited to EV owners). Why would you replace a perfectly good working battery without load testing it to see if it needs replacement?

But you’d spend $200 on a noisemaker “exhaust” for your electric car… if it were that cheap, of course.

 

[nuMach]

load test - we're thinking the same thing .... but the new tech doesn't load test in the traditional way.

its actually measuring the battery's internal resistance, but you need to 'calibrate' it to the chemistry used, and capacity.


more a battery analyzer. load tester is antique tech these days.

Shops now have access to very expensive analyzers that work on the same principle.

The amazon offerings are like a cheap radioshack multimeter as opposed to the shops kilobuck 5 digit bench meter .... but who cares if all you want is continuity as opposed to ohms , or volts to 3 decimals. The inexpensive model will do just fine.

 

[dtbaker61]

I think I would wait my 3 years under warranty and then replace it. Most of the cars in SoCal can do 3 years unless the battery was abused.

Where I live, experience has shown batteries last around six years, which is when I replace them proactively. They still start vehicles, but my testing shows they have significantly reduced capacity (e.g. 50% of new) which increases the chance of having a dead battery.

It's sort of like tires, you don't want to wait until you hydroplane to replace them. Replace the battery when it shows signs of reduced capacity.

FYI, load testing the battery is not the whole story. A battery can test good for cranking amps, but have horrible capacity. Capacity is more important than cranking amps for an EV.

I did buy a cheap ($35) battery tester on amazon. not concerned with cranking amps, but I did get one where you can enter the type (AGM), and CCA (35). My 40 month old 12v AGM shows "100% SOH - great condition".

The only maintenance I do is leave the car 'on' for a day or two every 10,000 miles to desulfate since I mostly drive 20-30 miles a day.

so.... either our batteries can last a LOOOOOng time, or the tester is not very accurate.

 

[scipioap]

Timely thread—received the “Stop safely now” message on my Select SR AWD 10 days ago while leaving the office, 3 weeks shy of my 3 year delivery anniversary, and only 12k mileage. The HVB charge was at 70%. So had Roadside Assistance tow to my local dealer (I had to figure out how to put it in neutral for towing BTW). But that dealer is swamped, and still hasn’t even diagnosed. I did open a case with Ford corporate, BEV team, but all they can do is advocate for me with dealer. Trying to diagnose on my own, the FordPass app is no help. But after towing, the car entered deep sleep presumably to preserve battery, so I discovered from my Ford.com page that the 12v was only at 19%, which has since dwindled to 2% then 1% and now 0%. So to expedite, I ordered a BAGM-H3 on my own with coupon from FordParts. com for pickup at that dealer, since it only reported a 1-2 day lead time. But that was a week ago and is still ‘Processing’. So bottom line on whether to proactively replace 12v is the timing in all of this. I would have done it if I knew.

 

[Chuck]

Timely thread—received the “Stop safely now” message on my Select SR AWD 10 days ago while leaving the office, 3 weeks shy of my 3 year delivery anniversary, and only 12k mileage. The HVB charge was at 70%. So had Roadside Assistance tow to my local dealer (I had to figure out how to put it in neutral for towing BTW). But that dealer is swamped, and still hasn’t even diagnosed. I did open a case with Ford corporate, BEV team, but all they can do is advocate for me with dealer. Trying to diagnose on my own, the FordPass app is no help. But after towing, the car entered deep sleep presumably to preserve battery, so I discovered from my Ford.com page that the 12v was only at 19%, which has since dwindled to 2% then 1% and now 0%. So to expedite, I ordered a BAGM-H3 on my own with coupon from FordParts. com for pickup at that dealer, since it only reported a 1-2 day lead time. But that was a week ago and is still ‘Processing’. So bottom line on whether to proactively replace 12v is the timing in all of this. I would have done it if I knew.

How does one see their 12v battery status on the Ford.com page? I can't find it anywhere.

 

[nuMach]

I did buy a cheap ($35) battery tester on amazon. not concerned with cranking amps, but I did get one where you can enter the type (AGM), and CCA (35). My 40 month old 12v AGM shows "100% SOH - great condition".

The only maintenance I do is leave the car 'on' for a day or two every 10,000 miles to desulfate since I mostly drive 20-30 miles a day.

so.... either our batteries can last a LOOOOOng time, or the tester is not very accurate.

was maintenance officer for a while with our marine rescue unit. Unit itself had a dozen batteries, plus everyone's personal boat, vehicle, and bike seemed to need a check. The topdon and im sure others in its class does a bangup job.

The CCA value is one factor in the analyzer it uses in its calculation and is necessary for accuracy.

AGM batteries are built in a way that is far stronger than lead acid for shock and vibration. They should outlast lead acid easily.

What kills em is how they are used/maintained. Left undercharged, or overcharged too many times kills em quick.

The MME provides an AGM, so it'll be tuned to charge an AGM

your ICE cars come with lead acid, which requires different voltages for charge and float than AGM.
Using AGM in an ICE vehicle is a waste IMHO.

In marine use, eg. eith can be used (depending) as most shore-powered chargers for the house batteries can be set for either chemistry.
In powerboats, AGM would stand up better due to pounding from waves at speed.

Hours of trolling eg, runs the batteries down, and the motors alternator doesnt charge them at idle, so either chemistry takes a hit with this kind of use.

For the MME it comes down to how the 12v battery is charged in our use. Since it doesnt charge when sitting, long idle periods will benefit with a tender (that can be set for AGM chemistry)

 

[Mach-Lee]

I did buy a cheap ($35) battery tester on amazon. not concerned with cranking amps, but I did get one where you can enter the type (AGM), and CCA (35). My 40 month old 12v AGM shows "100% SOH - great condition".

The only maintenance I do is leave the car 'on' for a day or two every 10,000 miles to desulfate since I mostly drive 20-30 miles a day.

so.... either our batteries can last a LOOOOOng time, or the tester is not very accurate.

Again, those testers measure conductance or CCAs, and the SoH value is calculated based on cranking amps, not capacity. So you can have a battery test 100% SoH on the CCA scale and still have a low capacity.

The only way to test capacity is to perform a discharge test (e.g. how long does the battery run a light bulb before dying).

 

[scipioap]

How does one see their 12v battery status on the Ford.com page? I can't find it anywhere.

Once you sign in, from menu (top right) you go to My Account, and it should show the below (middle column is for 12v SoC). Oddly if I click on my vehicle health, it states my Mach-E is in “Excellent Health”. Go figure…

2021 Mustang Mach-E
VIN: XXXXXXXXXXXXXXXXX

Tire Pressure
Good
Charge Level
0%
Est. Distance
142 mi

 

[dtbaker61]

Again, those testers measure conductance or CCAs, and the SoH value is calculated based on cranking amps, not capacity. So you can have a battery test 100% SoH on the CCA scale and still have a low capacity.

The only way to test capacity is to perform a discharge test (e.g. how long does the battery run a light bulb before dying).

yeah... same for my solar stuff... the only real way to test takes hours on a big battery... usually with a known load at about 0.2C... and time it from 'float' 100% to 50% voltage... that works with lead batteries.... but not Lithium because the voltage curve is flat between 20%-80%.

I suppose with our little 12v batteries it wouldn't take all that long.

 

[nuMach]

Again, those testers measure conductance or CCAs, and the SoH value is calculated based on cranking amps, not capacity. So you can have a battery test 100% SoH on the CCA scale and still have a low capacity.

The only way to test capacity is to perform a discharge test (e.g. how long does the battery run a light bulb before dying).

they measure internal resistance, which when 'calibrated so to speak' with the parameters of volt, chemistry, and CCA come up with a % health,
They cant measure CCA as they just dont... that would be an old style load tester.

without spending $ on a tester, I agree with you about using an old headlight on a charged battery to see how long it lasts. Measure the current the load draws and compare it to the amp-hour rating of the battery.

more the point is, there are tools to give you a benchmark, ve working in the dark.

Always analyzer tested the new batteries Ive replaced as a sanity check. Never had one less than 100% on a new one. I dont feel they are gimmicky at all, but only feel that way now Ive had years of experience with one.

 

[ericNdfw]

That's just for the part, you would have to install it yourself. I imagine the dealer would charge extra to install it.
I don't think you have to remove the entire frunk tub, probably just the back center cover and the right side cover. I've never done it, but doesn't look hard.

It does require full tub removal.

https://www.macheforum.com/site/threads/official-instructions-to-replace-the-12v-battery-lvb.3882/

also:

 

[abfoot7818]

Speaking from the experience of having a Ford hybrid for 8 years and 115,000, my 12 V battery lasted over 100,000 miles and seven years. The hybrid does not have a 12 V starter, but rather would use a kick from the traction battery and the electric propulsion motor, which would essentially roll start the engine thus you would never hear a cranking sound of an engine starting. Unlike gas powered cars the Mustang Mach-e of which I put 16,000 miles on in our first year doesn’t have a heavy hard load that requires a lot of cold cranking amps to get your car going. You just need a very minor amount of energy from the 12 V battery to operate the computers that then run power from the high voltage traction battery stepped down to 12 V to charge your 12 V battery. I absolutely completely advise you not to replace the battery before the five years 60,000 or whatever the warranty is specifically for the 12 V battery replacing the battery especially with a non-Ford battery would short change you on the warranty besides not being needed. However, your suspicion and caution is not without merit. I had every single maintenance performed by a Ford motor company dealership, and I often thought it was odd that they said my 12 V battery pass the test as “great” less than 500 miles after they told me it was great my ford hybrid was dead and of course I left it with my father-in-law, who was taking care of our kids while I was out of state. I suspect when the dealership tested the battery, they ran the test on my hybrid as if it were a regular gas car and instead of having all of the power off of the battery, they were getting a false reading as my hybrid system sent power back to the 12 V battery, just like an EV keeps the 12 V battery charged without running an alternator. Hopefully dealerships are getting a little more educated about the different testing methods needed for EV’s 12 volt system versus gas powered 12 V systems.

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