Received 12V Battery Warning - Looking for some advice

[SteveInBend]

Had this happen to me last year (also a 2022 R1T), followed the advice to keep it plugged in and was no problem for 10 days when both 12v batteries were replaced. I did see more phantom drain as it seemed like the truck didnt go to sleep much.

https://www.rivianforums.com/forum/...able-after-first-dashboard-12v-warming.51438/

The truck hasn't been sleeping much, at all. Even before I received the warning.

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[zymolysis]

Last Friday I received the 12V battery warning on my '22 R1T. I am already scheduled for the FSAM-1794 recall service at the Tualatin SC on 3/17. Although the 12V battery replacement can be done via mobile service, Rivian has decided to suspend mobile service to Central Oregon while a local technician is being trained. As I understand it, this individual will be working out of Redmond, OR.

As others have mentioned, use a battery-tender type trickle charger (preferably with desulphation cycle). Do this for each battery (you can use one charger, and switch between them), as much as possible between now and the time you have to take it in to the SC. This should improve the health of your 12V batteries, to allow them to last longer.

 

[zymolysis]

The truck hasn't been sleeping much, at all.

If you charge them with trickle chargers frequently, it'll probably start sleeping more, due to improved health of the batteries.

 

[SteveInBend]

Was this before or after the 2026.03 update was installed on your truck?

I am curious what the 12V failure situation looks like after the changes in the recent update:

• Improved the ability for the vehicle to power on when the 12 V battery voltage is low.
• Improved control of the 12 V battery depth of discharge.
• Improved 12 V battery health diagnostics by checking battery state of power when the vehicle wakes up.

This happened after the 2026.03 update.

 

[narmstrong79]

I don't have any 12 volt warnings on my dash or in my app. But Rivian just called and scheduled me for a 12V replacement tomorrow, unfortunately no mobile service available which sucks.

What is the actual issue with the battery ?
Do they replace with new lithium ion ? The guy on the phone says yes, but he wasn't super confident in his reply.

I have a late gen 1 (2024) dual motor - so it should be the single 12V not the dual 12V - right ?

Should I disconnect my Comma Ai before dropping the car off ?

 

[VandalSibs]

I don't have any 12 volt warnings on my dash or in my app. But Rivian just called and scheduled me for a 12V replacement tomorrow, unfortunately no mobile service available which sucks.

What is the actual issue with the battery ?
Do they replace with new lithium ion ? The guy on the phone says yes, but he wasn't super confident in his reply.

I have a late gen 1 (2024) dual motor - so it should be the single 12V not the dual 12V - right ?

Should I disconnect my Comma Ai before dropping the car off ?

As far as I'm aware, they are NOT using Li-Ion for the 12v batteries. They are still more expensive than lead acid batteries.

And did they confirm that they can't do it as a mobile service? I just had my swap done a few weeks back - it was done in my garage (along with the 15k inspection)...

 

[UnsungZero_OldTimeAdMan]

As far as I'm aware, they are NOT using Li-Ion for the 12v batteries. They are still more expensive than lead acid batteries.

And did they confirm that they can't do it as a mobile service? I just had my swap done a few weeks back - it was done in my garage (along with the 15k inspection)...

Not only AGM is cheaper, it’s also less sensitive to cold temperatures than Lithium Ion. Especially those in cold climates, you want your EV to boot up even in winter, right? There is a reason Ohmmu’s LFP (also a Lithium Ion) has its own heating element and management software.

Folks, 12V failures is less about the battery’s chemistry. More about management of it (how much charge to draw from it, and how often to recharge it with power from the HV pack, given its size and demands placed on it). It’s also about balancing needs of those wanting more responsive proximity entry, versus those who are hawkish on vampire drain. A Lithium 12V doesn’t address any of these factors. It’s just blindly throwing more $ at a problem. Larger capacity could help as that provides more juice in reserve. But without correcting underlying cause of failure, it’d just be treating a disease with a bandaid.

 

[VandalSibs]

Not only AGM is cheaper, it’s also less sensitive to cold temperatures than Lithium Ion. Especially those in cold climates, you want your EV to boot up even in winter, right? There is a reason Ohmmu’s LFP (also a Lithium Ion) has its own heating element and management software.

Folks, 12V failures is less about the battery’s chemistry. More about management of it (how much charge to draw from it, and how often to recharge it with power from the HV pack, given its size and demands placed on it). It’s also about balancing needs of those wanting more responsive proximity entry, versus those who are hawkish on vampire drain. A Lithium 12V doesn’t address any of these factors. It’s just blindly throwing more $ at a problem. Larger capacity could help as that provides more juice in reserve. But without correction underlying cause of failure, it’d just be treating a disease with a bandaid.

 

[narmstrong79]

As far as I'm aware, they are NOT using Li-Ion for the 12v batteries. They are still more expensive than lead acid batteries.

And did they confirm that they can't do it as a mobile service? I just had my swap done a few weeks back - it was done in my garage (along with the 15k inspection)...

The part # on the work order reads "PT00044052-C" which a google search got me this

 

[VandalSibs]

Yeah, that's Lead Acid for sure. Sulfuric Acid & Pb (Lead) right on the label.

 

[CANCERDOC]

I would not wait to get the 12V replaced. Once the warning is there, there is no guarantee keeping it plugged in and charged up will preserve the 12V for another few weeks. Rivian prioritizes 12 V replacement, you can literally do a walk in appt and they will replace it on the spot.

 

[shamoo]

Coincidentally I was proactively called by Rivian to swap out my 12V. Mobile appoint is tomorrow.

Never got a warning and the last time I was in service (maybe a year ago?) I asked about it and they said only a certain range of VIN numbers would be impacted and I was not in the range.

But now apparently I have to swap it?

 

[KBabione]

Coincidentally I was proactively called by Rivian to swap out my 12V. Mobile appoint is tomorrow.

Never got a warning and the last time I was in service (maybe a year ago?) I asked about it and they said only a certain range of VIN numbers would be impacted and I was not in the range.

But now apparently I have to swap it?

They proactively replaced the 12V in our '23 R1S last January - I was actually blown away by a manufacturer who basically said: "We're monitoring the health of your car and noticed that you're going to have an issue sometime in the next couple of months so we'd like to come out and fix it for you now for free." NONE of my previous manufacturers (Audi, Acura, Subaru, Toyota) did that. Be grateful that they have the tech to identify this and to act on it.

 

[SteveInBend]

Thanks for everyone's help and advice regarding the 12V battery warning!

I thought I'd provide a quick update on where things stand:

Yesterday morning I used the RiDE menu to reset the 12V battery warning and it has not reappeared. I also have not experienced any issues while driving the car and have kept it plugged in the home EVSE and charged up to 80% when not in use. Hopefully, everything will be OK until I can drive over to the valley for my scheduled appointment on 3/17.

P.S. It snowed up at Mt. Bachelor yesterday but I'm not sure I want to drive up there and not be able to start the truck after a day of skiing.

 

[tate16t]

Done correctly, all settings are saved.

My battery was replaced this morning. It took about 30 minutes. Mobile service had a canvas umbrella connected to the R1T to protect my vehicle and parts from the rain. The only minor glitch I noticed via the mobile app was the tech left without taking the vehicle out of service mode. Good thing I noticed it within five minutes of him leaving the house. He came back and took care of it.

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