Sodium 12v replacement batteries coming from Ohmmu for Rivian vehicles

[MountainBikeDude]

I've been chatting back and forth with Ohmmu sales about potential for Sodium chemistry 12v battery replacements for my dual 12v battery Gen 1 R1T.

They had them in the pipeline, but since the 12v issues introduced in the 2025.38 update, they prioritized their development and testing. Currently they're testing them in various Rivian vehicles and expect to have them available to customers early next year.

See below for some of the benefits of a 12v Sodium battery over the standard lead acid Rivian equivalents. Credit to Gemini.

12V sodium batteries offer EVs major benefits like lower cost (abundant sodium), superior cold-weather performance (no heating needed, high cranking amps), enhanced safety (less fire risk), longer life (fewer cycles for degradation), and better environmental sustainability. They can replace heavy, shorter-lived lead-acid SLI batteries, providing reliable power for electronics, lights, and steering in extreme cold, potentially without complex Battery Management Systems (BMS).


Key Benefits of 12V Sodium Batteries in EVs:

• Cost & Availability: Sodium is abundant and inexpensive, reducing battery costs and reliance on lithium supply chains.
• Extreme Cold Performance: Performs exceptionally well in freezing temperatures (down to -40°C or lower), delivering high cranking power for starting accessories, unlike lithium batteries that struggle.
• Safety: Less flammable and prone to thermal runaway than lithium, increasing safety in the engine bay.
• Longer Lifespan: Offers significantly more cycles (e.g., 5,000+ vs. lead-acid) and lower degradation, potentially lasting the vehicle's lifetime.
• Environmental: More sustainable with lower energy required for production and processing.
• Simpler Design: Some designs operate within the standard 8-14.4V range for 12V systems, potentially reducing BMS complexity or eliminating the need for it.
• Lightweight: Smaller and lighter than traditional lead-acid batteries while providing superior power.

How They're Used:

• SLI (Starting, Lighting, Ignition) Replacement: They replace traditional lead-acid batteries for powering the vehicle's essential electronics, even in electric cars where the main battery powers the motor.
• Coexistence: They can work alongside main drive batteries, balancing supply chains and performance needs.

In essence, 12V sodium batteries offer a safer, cheaper, more durable, and better-performing alternative to lead-acid and even some lithium 12V systems for EVs, especially in cold climates.

Sponsored

 

[UnsungZero_OldTimeAdMan]

Lower cost wouldn't be meaningful unless the savings are passed on to consumers. I guess we'll see once price info is available. Greater cold-cranking power... Not sure BEVs need that. Longer lifespan, better safety, lower environmental impact are all good. Would be nice if it's also got greater capacity than stock.

 

[Nixapatfan]

Sounds like good news, hoping for better build quality and hoping Rivian updates the software to allow resetting the warning lights by the time I need these.

 

[Budman]

I Will only use if endorsed by Rivian. Sounds promising on paper but much we don’t know.

 

[UnsungZero_OldTimeAdMan]

I Will only use if endorsed by Rivian.

That will probably never happen, as it has not happened to any existing alternatives.

 

[MountainBikeDude]

Lower cost wouldn't be meaningful unless the savings are passed on to consumers. I guess we'll see once price info is available. Greater cold-cranking power... Not sure BEVs need that. Longer lifespan, better safety, lower environmental impact are all good. Would be nice if it's also got greater capacity than stock.

Clearly just benefits in general over a LA battery regardless of use case. I do wish the capacity was greater, but if Rivian is specifically looking for or only calibrated to recognize a total of 200ah, then I'm not sure how that would play out.

I'm thinking it would be akin to installing a larger capacity hard drive than a computer can recognize, it will only register it's allowable upper limit, with the remainder not being addressable

 

[Dark-Fx]

I think LTO is the best replacement for lead acid batteries in EVs, especially if you live somewhere that gets real winter. Sodium still doesn't like charging in below freezing temps, though it's slightly better than LFP in that regard. LTO is generally fine charging down to ~-40F/C.

The big problem when changing chemistries is the charging/discharging voltage behaviors are all different.

I personally see zero advantage switching away from lead acid on a Rivian, especially considering how closely they are trying to keep tabs on 12V health these days. I don't see Rivian attempting to guess what chemistry your 12V is made out of unless they start shipping non-lead acid batteries themselves.

 

[MountainBikeDude]

I think LTO is the best replacement for lead acid batteries in EVs, especially if you live somewhere that gets real winter. Sodium still doesn't like charging in below freezing temps, though it's slightly better than LFP in that regard. LTO is generally fine charging down to ~-40F/C.

The big problem when changing chemistries is the charging/discharging voltage behaviors are all different.

I personally see zero advantage switching away from lead acid on a Rivian, especially considering how closely they are trying to keep tabs on 12V health these days. I don't see Rivian attempting to guess what chemistry your 12V is made out of unless they start shipping non-lead acid batteries themselves.

I have low confidence in the longevity of the 12v oem batteries. I hope I'm wrong, but if the replacement ones I have fail within another year and half, I see no reason not to try an alternative, especially if facing an 800 swap cost

 

[ndmiller]

I have low confidence in the longevity of the 12v oem batteries. I hope I'm wrong, but if the replacement ones I have fail within another year and half, I see no reason not to try an alternative, especially if facing an 800 swap cost

I've been replacing batteries in all my vehicles for decades, Automobile and Motorcycle alike. Living in FL, TX, and GA the climate literally cooks them with heat a good portion of the year, so 3-5 years is regularly the observed lifespan even with top of the line Panasonics that come OEM in Lexus vehicles.

Having batteries fail in an EV is pretty much a given for me in 3-5 years as well and I'm in year 2, so expect next year or two I'm in for it. The R1T was $85K and a pretty darn complicated rolling computer, so again my expectation was when wear item things (Battery/Brakes/Tires/etc) wear out they will be expensive.

No way I'm putting a non-OEM battery chemistry in my R1T even if it was free, juice isn't worth the squeeze. Something leaks or explodes and it's on me alone, as Rivian first question is going to be where did you get a Sodium battery?

 

[Dark-Fx]

I have low confidence in the longevity of the 12v oem batteries. I hope I'm wrong, but if the replacement ones I have fail within another year and half, I see no reason not to try an alternative, especially if facing an 800 swap cost

All it takes is one really deep draw, or several just a bit too deep, and lead acid batteries become doorstops. Our UPS batteries at work started lasting a lot longer after we had a generator installed. They aren't getting discharged more than a few percent tops anymore.

 

[Captblue]

12v oem batteries are over priced…. Better off with OEM

 

[Jimflip]

I'm super interested in new battery chemistries and the various benefits.
Is there a recommended link/site to learn more?

Also, I seem to recall from a high school lab class (a very, very long time ago) that Na and water are "very much not friends".

I'd be curious how the battery is constructed to keep water/humidity out & also protect first responders etc. in the event of an accident?

 

[SwampNut]

My truck is on the fourth pair of batteries, and I'm now out of the battery warranty period. There's zero chance I'd buy OEM, even if they weren't 4x overpriced.

 

[Zoidz]

I'm super interested in new battery chemistries and the various benefits.
Is there a recommended link/site to learn more?

Also, I seem to recall from a high school lab class (a very, very long time ago) that Na and water are "very much not friends".

I'd be curious how the battery is constructed to keep water/humidity out & also protect first responders etc. in the event of an accident?

It uses a sodium metal oxide, not pure sodium, so water reactivity is not a concern. Pure lithium is also unstable, but again, batteries use a lithium metal oxide. Lithium batteries are more dangerous than sodium batteries.

Analogy: Hydrogen is highly reactive/flammable but when bound with oxygen it puts out fires.

https://en.wikipedia.org/wiki/Sodium-ion_battery
Sodium-ion batteries have several advantages over competing battery technologies. Compared to lithium-ion batteries, sodium-ion batteries have somewhat lower cost, better safety characteristics (for the aqueous versions), and similar power delivery characteristics, but also a lower energy density (especially the aqueous versions).[80]

 

[MountainBikeDude]

I've been replacing batteries in all my vehicles for decades, Automobile and Motorcycle alike. Living in FL, TX, and GA the climate literally cooks them with heat a good portion of the year, so 3-5 years is regularly the observed lifespan even with top of the line Panasonics that come OEM in Lexus vehicles.

Having batteries fail in an EV is pretty much a given for me in 3-5 years as well and I'm in year 2, so expect next year or two I'm in for it. The R1T was $85K and a pretty darn complicated rolling computer, so again my expectation was when wear item things (Battery/Brakes/Tires/etc) wear out they will be expensive.

No way I'm putting a non-OEM battery chemistry in my R1T even if it was free, juice isn't worth the squeeze. Something leaks or explodes and it's on me alone, as Rivian first question is going to be where did you get a Sodium battery?

I get it, I've also done enough 12v replacements over the years to know my "good window" is usually around 2-3 years. My issue is two fold though with EV's and 12v batteries, when they do go, you're essentially fucked and dead in the water, sure you can jump it to gain access to the vehicle, but doesn't mean you're able to get the contactors on the HV battery to close and allow you to drive.

ICE vehicle, I can jump a dead battery, and the alternator once started, will keep the vehicle running. So, given I take my vehicle out and about often I'm rolling the dice either with an unknown battery, or a battery that seemingly just notifies me of a failure potentially moments before it happens, I'd rather go with something that has at the very least, the potential to last longer.

On the cost and higher priced maintenance, It was mostly understood when I bought a Gen 1 vehicle that part replacements were going to be a thing. Especially so with the more bespoke suspension, and my driving habits. That said, even if there was a cost parity across the Rivian OEAM LA battery and the Ohmmu Sodium replacement, I would take the opportunity to install a consumable "upgrade" that will take me further.

Also, I don't think I've ever seen an OEM endorse a non OEM replacement component.

Edit* This sounds very dickish in my response, not meant to be, just trying to guzzle some coffee, type, and run. Forgive me.

Sponsored