Rivian R1S Gen 1. 12 V Battery Replacement. Again!

[bigsky]

Rivian replaced the 12 V battery on my R1S Gen 1 at 6.5k miles in May 2025.
Got an alert on the Rivian app today to "Replace the 12 V battery." Only 12k miles on the odometer.

Last three days, VD on my Rivian went full blast losing 10 miles/3% SOC daily just sitting in my garage. Nothing has changed. Then, I noticed the above alert on the app today. Don't know if the awful VD and the 12 V battery warning are related.

What I do know is that Rivian reliability is starting to look, well, typical and extremely worrisome. This is garbage. It would be laughable to ask "have you seen this?" Of course, many have.

There is just no excuse for this. Even in my ICE cars, 12 V batteries lasted 5 years. Heck, the 12 V battery in my glorious Teslas, one 6 years old; the other 4 years old still the original and running like champs. But, of course, we are talking Tesla here. Nothing else compares, much less Rivian, the supreme leader of unreliability, it seems.

Fortunately, all these issues are covered under warranty, but another 12 V battery replacement , the CV boot leaking, the clunking suspension, all become the proverbial canary in the reliability mine post-warranty. I am hopeful that there will be very good alternatives to my R1S when the warranty expires and I ditch this thing, which I had hoped to keep for years. No way.

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[TTedP]

Gen 1? Two battery set up or one?

On Reddit, there is an ex SC employee who says Gen 1, one battery set up -> 12-18 mos is all you can expect out of that model. No fixing the design. A dual battery Gen 1 (earlier VIN) will last longer as will a Gen 2 single battery with the newer architecture.

I had a Gen 1 single battery VIN and sure enough, my 12v was changed after one year. Vampire drain on that one averaged 2% per day. On my Gen 2, I am only seeing ~1% per day even with all the app connectivity left on.

 

[bigsky]

Yes, only one battery as well. Not sure why the service order said "batteries."
Like yours, mine was doing fine; drain was at most 2 miles per day.
A 12 V battery tender cannot keep up. Forever blinking, which means battery at 50% or not 100% charged.

 

[Megaman0025]

Rivian replaced the 12 V battery on my R1S Gen 1 at 6.5k miles in May 2025.
Got an alert on the Rivian app today to "Replace the 12 V battery." Only 12k miles on the odometer.

Last three days, VD on my Rivian went full blast losing 10 miles/3% SOC daily just sitting in my garage. Nothing has changed. Then, I noticed the above alert on the app today. Don't know if the awful VD and the 12 V battery warning are related.

What I do know is that Rivian reliability is starting to look, well, typical and extremely worrisome. This is garbage. It would be laughable to ask "have you seen this?" Of course, many have.

There is just no excuse for this. Even in my ICE cars, 12 V batteries lasted 5 years. Heck, the 12 V battery in my glorious Teslas, one 6 years old; the other 4 years old still the original and running like champs. But, of course, we are talking Tesla here. Nothing else compares, much less Rivian, the supreme leader of unreliability, it seems.

Fortunately, all these issues are covered under warranty, but another 12 V battery replacement , the CV boot leaking, the clunking suspension, all become the proverbial canary in the reliability mine post-warranty. I am hopeful that there will be very good alternatives to my R1S when the warranty expires and I ditch this thing, which I had hoped to keep for years. No way.

Would not something like one of the LFP Ohmmu batteries simply just fix this problem? It’s not a “reliability” issue - the batteries are simply being cycled to death.

 

[mkg3]

The HV battery is supposed to keep the 12V battery charged. So the problem may be more upstream that caused the 2nd battery failure due to consistent low charge. Rather than just have the battery changed, I would have Rivian take a look at the HV to 12V charging system.

As a side note, my Tesla 12V battery was changed under warranty just short of 5 years. So if your Teslas have the original batteries, they may be living on a borrowed time.

 

[MountainBikeDude]

Would not something like one of the LFP Ohmmu batteries simply just fix this problem? It’s not a “reliability” issue - the batteries are simply being cycled to death.

I'm planning to swap to Ohmmu when the time comes, I'm hoping the DIY service menu is in place by that time.

My Jan '23 build R1T had it's 12v's replaced this time last year. So nearly 2 years, not bad I suppose.

 

[ENVErider]

The HV battery is supposed to keep the 12V battery charged. So the problem may be more upstream that caused the 2nd battery failure due to consistent low charge. Rather than just have the battery changed, I would have Rivian take a look at the HV to 12V charging system.

As a side note, my Tesla 12V battery was changed under warranty just short of 5 years. So if your Teslas have the original batteries, they may be living on a borrowed time.

@mkg3, there are some good deep dives on this known Gen1 issue, and reporting is that the HV does indeed charge up the 12V battery, but it's not a direct wire connection with a voltage step down. It's been many months since I read up on this topic, but I believe the 12V runs standby services while asleep. When 12V gets to a low state of charge, the controllers partially wake up, run off HV battery, refill the 12V, and then go back asleep. This repeated "cycling" is what causes the 12V to fail relatively quickly, partly because the batteries are small and partly because Rivian chose lead-acid chemistry. I have seen others report success with homemade trickle charges tied directly to 12V and others reporting success with the lithium. I think this guy was one of the YouTubers that I watched earlier this year.
@bigsky based on this, I don't think your odometer has much impact on the 12V battery life, the use time/age is going to be a bigger factor in when it fails. Sorry to hear of the issue, reporting is that vampire losses have improved over time, but this battery issue might be one that is baked into Gen1 vehicles that OAT updates can't correct. I'll probably try lithium when my Gen1 12V eventually fails.

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