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12V battery replacement poll

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


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RLXXI

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One will see higher current if the ac/ heat is on, key on and running the water pump, abs pump etc, and Is also why a 75-100A charger is recommended connected when programming.
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DCAZEV

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I Live in AZ and I learned the hard way (in the past with my other ICE vehicles). I replace my 12V batteries at the 24 month mark. Most dealerships and auto parts stores down here in AZ recommend replacing the 12V batteries between 18 & 36 months. I don't like the idea of being stranded (anywhere). Rock Auto has the 12V batteries for like $110 or so. Cheap insurance in my opinion. (I also use my truck for truck, so any down time requires a rental vehicle, etc.).
 

sicamoose

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I have a '22. Mine was replaced under warranty 2.5 years into ownership
 

chl

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Assuming those high charging current measurements people are reporting are really the battery charging current and do not include the DC-DC converter powering other 12v systems, then I would say the battery involved is deeply discharged, and may (probably) become damaged by the high charging current being seen.

This is my reasoning - if there is anything you see wrong with it, please let me know.

----

In general, an AGM battery's charging current should not exceed 30% of the Ah rating.
For the Lightning batteries, this is 0.3 x 35(Ah) = 10.5A.

The Lightning Battery Management System sensor for the 12v battery, along with the other components of the Battery Management System for the 12v battery, controls the charge voltage applied to the battery but it should also limit the charging current to no more than 10.5A to avoid damaging the battery.

The lower the 12v battery state of charge, the lower the internal resistance and the higher the current will be when a charging voltage is applied. The charging voltage for an AGM typically 14.5V or so, but generally no more than 15V.

However, an AGM battery with a very low state of charge should be charged slowly with an initial low current to avoid battery damage. That is the current has to be controlled by the battery management system/charger.

The same lower current requirement is true of a damaged AGM battery. A damaged AGM battery's internal resistance will be higher than normal due to sulfation and it should be charged at a lower current for a longer time to avoid further and permanent damage.

Therefore, I think that if the 12v battery charging current is really above 10.5A as some are reporting, that is a sign of:
(1) a depleted battery (SOC below 40-50%), and
(2) a Battery Management System that is not limiting the charge current to a safe and acceptable level of below 10.5A.

This will result in a shorter battery lifespan and damage to the battery.

----

The solution I am using to avoid damage to the 12v AGM battery and avoid premature battery failure is to keep the battery topped off my using a trickle charger with an AGM mode when the truck is not in use.
 

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21st Century Truck

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I proactively replaced my (second) OEM 12 volt battery at the 3 year mark with an Ohmmu Li-H3-BH (LFP) battery. It is definitely expensive, but I am very happy with results. It stays in the 90% to 100% SOC range, and SOC is viewable within Bluetooth range on a mobile phone.

I am not associated with Ohmmu in any way. They are offering a 20% Black Friday discount at the current time.

https://www.ohmmu.com/?utm_campaign...mail&cid=2cedc2fc-640b-47df-a436-dcc68464e997
Thanks for this.
 

DarkL1ghtn1ng

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I have a '23 bought in January of that year. I am on at least battery #3. All replaced under warranty.
 

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?
I obtained another data point today via the Ohmmu app. Although SOC is shown at 100%, I have noticed several times of charging for a few minutes to top off the battery. The attached screen copy shows 55.01 amps to the Ohmmu 12 volt battery. This number slowly reduced down to about 1.25 amps after 2 to 3 minutes. After returning home from a 25 mile trip with 2 stops, the app showed 12 volt SOC at 100% with 0 amps in/out.
 

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RLXXI

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I obtained another data point today via the Ohmmu app. Although SOC is shown at 100%, I have noticed several times of charging for a few minutes to top off the battery. The attached screen copy shows 55.01 amps to the Ohmmu 12 volt battery. This number slowly reduced down to about 1.25 amps after 2 to 3 minutes. After returning home from a 25 mile trip with 2 stops, the app showed 12 volt SOC at 100% with 0 amps in/out.
That's the beauty of the lfp battery having its own bms. Once it sees a full charge, it shuts off any external charging to prevent damage.
 

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htobin

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Wow! All this sounds so complicated. With a gas engine you replaced the battery when you needed a jump start. Apparently that strategy doesn’t work so well for an electric car
 

mr.Magoo

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Wow! All this sounds so complicated. With a gas engine you replaced the battery when you needed a jump start. Apparently that strategy doesn’t work so well for an electric car
It's only as complicated as you make it, the principle for replacement haven't really changed.
 

bmwhitetx

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Wow! All this sounds so complicated. With a gas engine you replaced the battery when you needed a jump start. Apparently that strategy doesn’t work so well for an electric car
Some people are making this appear complicated. It’s not. If you get notices that your 12V is having issues, have the battery checked and replaced if needed. Or just replace every x years.

Just in case, learn how to open the frunk with a dead battery so you can jump start it just like a gas vehicle.
 
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bthanos

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I proactively replaced my (second) OEM 12 volt battery at the 3 year mark with an Ohmmu Li-H3-BH (LFP) battery. It is definitely expensive, but I am very happy with results. It stays in the 90% to 100% SOC range, and SOC is viewable within Bluetooth range on a mobile phone.

I am not associated with Ohmmu in any way. They are offering a 20% Black Friday discount at the current time.

https://www.ohmmu.com/?utm_campaign...mail&cid=2cedc2fc-640b-47df-a436-dcc68464e997
I got the Ohmmu Battery as well. No issues at all so far. Hope it lasts a long time
 
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mr.Magoo

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I got the Ohmmu Battery as well. No issues at all so far. Hope it lasts a long time
For every "Ohmmu is amazing" post there should be a mandatory warning post with this:


or - at a bare minimum a disclaimer mentioning that they're not suitable for vehicles being used in cooler climates (that see below freezing temperatures).


Ohmmu might be great for some, but it is definitely not a solution for everyone.
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