12v Lead Acid Battery Replacement

[ksujeff99]

Nog just the 12v warning—if the truck isn’t going to sleep either, then it’s detecting lower than expected voltage, which is typically a sign of a dying 12v battery. Not sure how that would work with the Ohmmu 12v LFP battery though.

Both my Ohmmu batteries are reporting 13.5V in the bluetooth connectivity app and verified on the battery posts. That voltage must be dropping below a certain threshold when a load is applied.

The 12V error came back a few days ago. I reached out to Ohmmu support.

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[mudito]

Both my Ohmmu batteries are reporting 13.5V in the bluetooth connectivity app and verified on the battery posts. That voltage must be dropping below a certain threshold when a load is applied.

The 12V error came back a few days ago. I reached out to Ohmmu support.

I have a VERY Strong suspicious that Rivian changed their 12V charging algorithm and voltages in 2025.34 version software.

I have the "before" voltages but I haven't taken an "after" yet, but I do see my 12V charging behaving VERY differently after that update. If I have to guess, I think Rivian is now start charging at a higher threshold voltage than before.

Maybe this is triggering issues for users like you where the Ohmmu has a certain logic to worth with.

 

[mkhuffman]

I have a VERY Strong suspicious that Rivian changed their 12V charging algorithm and voltages in 2025.34 version software.

I have the "before" voltages but I haven't taken an "after" yet, but I do see my 12V charging behaving VERY differently after that update. If I have to guess, I think Rivian is now start charging at a higher threshold voltage than before.

Maybe this is triggering issues for users like you where the Ohmmu has a certain logic to worth with.

What are you using to determine the 12V charging behavior has changed?

 

[mudito]

What are you using to determine the 12V charging behavior has changed?

electrafi.com Sleep and Wake cycles. With and without a battery tender. With one connected I saw a big change and that sparked my curiosity

 

[csharp]

I just had my 12v replaced this morning via mobile tech. He let me know that I was one of the guinea pigs for the new remote reset that owners will be able to do. He did the entire thing without hooking up his laptop to perform the resets. He was on the phone with one of the engineers the entire time as the engineer monitored everything remotely. Tech said they are testing for the next month or so and we should see it pushed out s00n.

 

[mudito]

I just had my 12v replaced this morning via mobile tech. He let me know that I was one of the guinea pigs for the new remote reset that owners will be able to do. He did the entire thing without hooking up his laptop to perform the resets. He was on the phone with one of the engineers the entire time as the engineer monitored everything remotely. Tech said they are testing for the next month or so and we should see it pushed out s00n.

this is great to hear!

 

[variableresults]

electrafi.com Sleep and Wake cycles. With and without a battery tender. With one connected I saw a big change and that sparked my curiosity

What change did you notice? I just had mine swapped out (dead within 24 months of last death), and I notice my sleep time is way longer than it was before.

 

[mudito]

What change did you notice? I just had mine swapped out (dead within 24 months of last death), and I notice my sleep time is way longer than it was before.

Sleep time is one change. I was getting 11-15hrs of sleep and now I can't get more than 7 even if connected to a battery tender. I'm still making some measurements and tests so I can better compare with my precious ones.

 

[zymolysis]

my precious ones

My Rivian, my preciousss...
I am assuming it was intended to be "my previous ones."

 

[mudito]

My Rivian, my preciousss...
I am assuming it was intended to be "my previous ones."

Lol!!

Previous!!! Cell phone autocorrect

 

[UnsungZero_OldTimeAdMan]

Lol!!

Previous!!! Cell phone autocorrect

Those autocorrects are dangerous. First thing I disable ever since I once told a coworker to BCC someone else and autocorrect turned to BBC. That, took a totally wrong turn.

 

[Zoidz]

Those autocorrects are dangerous. First thing I disable ever since I once told a coworker to BCC someone else and autocorrect turned to BBC. That, took a totally wrong turn.

 

[epowermarine]

I just had my 12v replaced this morning via mobile tech. He let me know that I was one of the guinea pigs for the new remote reset that owners will be able to do. He did the entire thing without hooking up his laptop to perform the resets. He was on the phone with one of the engineers the entire time as the engineer monitored everything remotely. Tech said they are testing for the next month or so and we should see it pushed out s00n.

This is great news, but unfortunately it won't help those of us who have DIY swapped in new batteries and have the 'replace 12v battery' error. Because with this error the truck won't update, so I won't be able to get this new software tool to load. I scheduled a remote service appointment for early Dec in hopes that the tech can just plug in the laptop and hit a couple of keys to clear it. What a pain in the ass this situation is.

 

[Riviot]

I just had my 12v replaced this morning via mobile tech. He let me know that I was one of the guinea pigs for the new remote reset that owners will be able to do. He did the entire thing without hooking up his laptop to perform the resets. He was on the phone with one of the engineers the entire time as the engineer monitored everything remotely. Tech said they are testing for the next month or so and we should see it pushed out s00n.

Awesome, another "feature" to fix a 4 year old problem that no other vehicle on the market has. But first, we gotta make sure that swamp buggy has the right animations and colors. Thanks, @Wassym !

 

[mkhuffman]

Awesome, another "feature" to fix a 4 year old problem that no other vehicle on the market has. But first, we gotta make sure that swamp buggy has the right animations and colors. Thanks, @Wassym !

Can you clarify what the "4 year old problem" is? I am not convinced it is Rivian specific, but maybe I don't understand what you are referring to.

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