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12V battery replacement poll

Will you replace your 12V battery proactively or when it fails?


  • Total voters
    96

hturnerfamily

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While I've no issues with my ~40+month original LVB battery, with a truck build date of July 22, and probably the battery itself built several months before that, my recent 'red ring of death' non-chargeable issue made me consider the LVB as a potential culprit - or, at least I had hoped it would be that simple.

I was forced the remove almost everything from the frunk - wow! who would've thought you could hoard -away that much junk! Tools, emergency items, charge EVSE and cables, adapters, a folding chair, and more... : )

I removed the sliding door cover to the LVB, although I also realized now that I could have saved myself some time and convenience by simply using the external 'jumper' studs...anyway, I applied my trickle-charger's alligator clips to the primary battery terminal bolts(not the accessory terminals), and plugged in the charger. While I don't have a battery voltage checker, I felt like the battery showing 'Charging' would be an indicator, and I would then let it charge for several hours, or until 'full', if it was low...

after a while, I tried plugging in my EVSE again - no go. Still the red-ring.

The LVB was still charging. The small trickle-charger only has a 'blinking' Green light as a charging indicator.

I then set out to take a picture of the LVB battery size/type, and use that to research a replacement, as I imagined that this would be the answer to my charging woes. Even if not, with the truck over 3 years 'young', and over 62,000 miles, it was 'time', anyway...
FoMoCo BHAGM-H3 12V 35Ah 60RC

Well, I quickly found that no 'in-stock' options lie in the local area, from the typical sources, and even the Ford dealer had none. I then set out to contact my selling dealer, instead, as I was heading back down south near that location the next day, anyway, in my wife's car. Nope, none there, either, although they put me onto another dealer, within 25 miles from me, who DID have it in stock, and, I might add, at the much lower attractive price, versus what some online sources had quoted. $132 vs $200 or more. All of the online sources also add a nice big 'shipping' cost, too., and how would you then also receive your 'core charge' credit? Who knows... because....

Since the local Ford dealer could get me in that day, I let them also do a diagnosis, planning that it was really only the LVB as the real issue. It was not.. as they could immediately and clearly see, thru the truck's data, that the LVB was just fine, and actually at 97% capacity. The HVB, though, was where the issue lie - module 7, cell 63, was at about 3.8volts, versus all others at about 4.8, or something like that. That module replacement is a different story for another time : ) but, successful, I might add.

So, in the end, I still don't have a 'new' LVB, and, well, until it starts to give me fits, it will continue to serve me until then... I have a follow-up module replacement APPOINTMENT on Tuesday, to check coolant levels, AND the LVB status, just in case. A tire rotation can't hurt, too.

yes, I could simply go out and get that replacement LVB, put it in the bed, and ride around with it as my 'backup', until needed... but, then, the warranty period would start at that purchase date, rather than when you actually start using it. Oh well. Hard choices.
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Lytning

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On an associated 12 volt battery topic ... I am curious what others have seen regarding the charging current to their 12 volt battery. Using the Car Scanner app on CarPlay, I recorded 43 amps. On another short trip, which I did not record, I seem to remember 72 amps. Has anyone else recorded or observed their charging 12 volt charging amps?
 

mr.Magoo

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chl

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I find those relatively high charging current numbers rather alarming and wonder if they are accurate?

High charging currents reduce the lifespan of batteries significantly.
Lower charge currents extend the life span of batteries.

The Lightning 12v battery is a 35Ah AGM battery.

Generally a max charging current of 20% to 25% of the Ah capacity is a rule of thumb for lead-acid batteries in general.

For AGM batteries 30% of Ah capacity is often specified as the max current. That would be 10.5A for a 35Ah battery.

But sometime 40% of Ah capacity is specified as a safe max, which would be 14A max.

Because it is an AGM, it goes through a series of charge stages, bulk, absorption and float, from high to low current.
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Bulk is a constant, high current stage which quickly bring the voltage up until it reaches approximately 14.4V or so, the absorption voltage.

During the absorption stage the charger holds the voltage at the absorption voltage as the current decreases until it reaches a particular level depending on the battery capacity.

During float, the voltage is reduced to a constant voltage of around 13.5V or so to keep the battery at 100% but not overcharge it.
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According to the Ford documentation about the Lightning charging system, the DC-DC converter will provide 300Wh of energy when the battery reaches 40%, that is, needing 21Ah to be full at 35Ah.

That indicates a charger voltage of 14V from the DC-DC converter:
300Wh/14V=21Ah

Using the 14A rule of thumb for an AGM battery max current, it would take 1.5 hours to fully charge (bulk stage) from 40% to 100%: 21Ah/14A=1.5h That is reasonable and typical.

If those high current numbers being reported are accurate, it could be one reason why the Lightning AGM batteries fail regularly in under 3 years time.

So I wonder...
 

Lytning

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I find those relatively high charging current numbers rather alarming and wonder if they are accurate?

If those high current numbers being reported are accurate, it could be one reason why the Lightning AGM batteries fail regularly in under 3 years time.

So I wonder...
I believe the 43 amps is correct. However, after reading your comments, I realize that I assumed that all of that current was charging the 12 volt battery. I have attached a photo of the Car Scanner data display, which shows the 43 amps was DC-DC Low Voltage. It is certain that a portion of that current was being used by other 12 volt devices, and not all being used to charge the battery. From "random" observations of 12 volt battery SOC while driving, it does seem that the 12 volt battery charges more quickly than I would expect.

Ford F-150 Lightning 12V battery replacement poll Car Scanner Display
 

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NW Ontario Ford Lightning

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I really like the idea of a 12v DC charging point at the HV-plug area like Chi shows.
I would like a nice neat bulkhead style fitting for the truck side - and then a convenient plug adapter to fit the bulkhead fitting end.
Mayby a KWAY type fitting? something that looks like it belongs inside the HV-plug cover?
 

mr.Magoo

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I find those relatively high charging current numbers rather alarming and wonder if they are accurate?
I'm afraid they are....

I'm using the battery current PID for those graphs.
0x22402BBAT_CURRENT

For a second I thought I might have screwed up my configuration (although it has registered negative currents in the past) so I made a test this morning to verify.
10mA on the clamp meter is 1A, so, 30mA is 3A, picture was taken at 7.56am
Also added the DC/DC charger PID for reference. (it only logs every 5 min, so not as granular)

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TaxmanHog

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Continuing the tangential topic of cool/cold weather pre-conditioning.

Since yesterday into this morning, temps were not as cold lows in the 40's with rain rolling in from the S/W, this mornings conditioning routine while on the plug used less than half the energy as yesterday, possibly some residual carry over heat in the pack and just not as cold.

Process started at 0712, ready to drive at 0755, unplugged at 0800, using 4.32 kWh of energy.

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The Weatherman

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I am going to have to change my poll vote. From: Replace on Fail -to- Other

I have ordered an OHMMU Lion spec for the Lightning.

The truck is showing early signs of LVB degradation. It is slipping into Save Battery mode too frequently for my taste now.

It is a very early 22MY dealer first delivery Mannequin (BD 3/31/22) which makes the 12V battery likely 4yrs old or older.

The OHMMU is a little pricey, but they are having a ‘BlackFriday’ sale going on now.

Looking forward to its arrival probably sometime after Thanksgiving.
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