12v Lead Acid Battery Replacement

[mudito]

I do not understand why Rivian and other EV 12v batteries are not user replaceable.

They are user replaceable, but they are uncommon in size and AH capacity vs legacy automotive 12V batts. You can source replacements online vs a short trip to the corner Auto Zone and you can manually pop the frunk and replace then in less then an hour. Certainly not as simple as with a legacy vehicle, but not really difficult either compared to other automotive repairs.

And... After the DIY replacement, there's a service menu option to run the health check, reset, and diagnostics:
https://www.rivianforums.com/forum/threads/12v-lead-acid-battery-replacement.34985/post-643881

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[Singletracker]

If these batteries are failing from too many recharge cycles, why aren’t they using deep cycle batteries designed for this sort of abuse?

 

[mudito]

If these batteries are failing from too many recharge cycles, why aren’t they using deep cycle batteries designed for this sort of abuse?

They are using exactly those ones

I've heard notes from techs saying they have wayy too many Batteries failing from a specific bath (it's hearsay, so take it for what it is ). Only time will tell

 

[PatientIsopod]

Small update, I got curious and decided to look at the RIDE menu to see my voltage (ignore the dust):

From what I have read, this is actually the normal voltage for the 12V. Is that accurate? If so, why did I get the replace message? To be clear, I checked this while unplugged and after a drive.

 

[godfodder0901]

Small update, I got curious and decided to look at the RIDE menu to see my voltage (ignore the dust):

From what I have read, this is actually the normal voltage for the 12V. Is that accurate? If so, why did I get the replace message? To be clear, I checked this while unplugged and after a drive.

During a drive, or when the vehicle is 'Ready' - yes. Stable is ~12.6v and charge is ~14.35v.

 

[W in NC]

I got the "Replace 12V Battery" message yesterday, luckily for now my truck is still able to drive. I sent Rivian a mobile appointment request (I live almost 2 hours away from the nearest service center) and unfortunately the next window they'll be out in my neck of the woods is in December, more than a month away. They told me I could drive it during this time as long as I kept it plugged in as much as possible. Should I trust that? The threads I've read here make me think that I'm going to get stuck somewhere.

In the mean time, I saw videos and threads describing how to replace these, which definitely seems like something I could DIY. The trouble is that I don't want Lithium batteries as I live in a cold area, and unfortunately that's the only non-OEM battery I've seen people use. Is there a lead-acid replacement for these that has the posts in the right spots?

Thanks for your help.

Just had my 12V battery replaced yesterday by Rivian Mobile Service. I was initially notified by phone by Rivian just a few days ago. Apparently models within a certain VIN range were reported to have battery failures, prompting higher priority for replacement service.
The first thing the technician did was disconnect the 400V cable. Also, a few resets were done afterwards to inform the car that the new battery was in place. It is a rather innocuous looking battery, but I’m glad Rivian service did the replacement, I think there is a finite potential for a screw up by DIYers, I wouldn’t want to risk warranty issues if some electronic bug appearef.

 

[PatientIsopod]

During a drive, or when the vehicle is 'Ready' - yes. Stable is ~12.6v and charge is ~14.35v.

Interesting. I wonder if this is one of the reasons Rivian doesn't seem very concerned about my issue. I suppose the real test would be to unplug it for awhile and check the voltage then, but I'm kind of nervous to do something like that. I'm also curious to know what metrics cause the alert to trigger, like is it charge/discharge rate, voltage, maybe both, or something else?

 

[mudito]

Interesting. I wonder if this is one of the reasons Rivian doesn't seem very concerned about my issue. I suppose the real test would be to unplug it for awhile and check the voltage then, but I'm kind of nervous to do something like that. I'm also curious to know what metrics cause the alert to trigger, like is it charge/discharge rate, voltage, maybe both, or something else?

The tell tell point is the frequency of 12v recharge. My voltage (brand new batteries) is the same-ish as yours, but it can go 16 hours in sleep without a charge (wake event)

 

[k3g]

The first thing the technician did was disconnect the 400V cable.

I'm looking again at the photos I took with my frunk tub out, and I don't understand why they would need to touch any of the HV connections. There's none in the direct area of the 12v batteries, unless I'm missing something. Which one did they unplug?

 

[mudito]

I'm looking again at the photos I took with my frunk tub out, and I don't understand why they would need to touch any of the HV connections. There's none in the direct area of the 12v batteries, unless I'm missing something. Which one did they unplug?

That thingy I think is the one they unplug. Purely for safety and no other reason. I might assume that it's also to avoid the DC-to-DC charger to try to supply voltage to the 12V when swapping them out, but just my imagination.

 

[W in NC]

Yes, it is the red cord which carries 400v, this wire is positioned for easy access by firefighting personnel. The yellow labels indicate where is cable can be sheared in an emergency.
I believe the HV cable was disconnected as a safety practice by the technician.

 

[JackRussellRacing]

IF I had a 12V warning (when mine died, it died at the same time as I saw the warning), I would eliminate the schedule (I have it from 8pm to 6am since I have $0 electricity at that time-frame), and keep it plugged in with a charge limit of 70%.

That is basically what I did, and it was fine. (I also turned off all gear guard stuff and rolled down the drivers window -- just to be super-duper safe). Mobile service replaced the 12v in a few days.

 

[wallyman424]

Yes, it is the red cord which carries 400v, this wire is positioned for easy access by firefighting personnel. The yellow labels indicate where is cable can be sheared in an emergency.
I believe the HV cable was disconnected as a safety practice by the technician.

The red cord does not carry 400v. It carries 12v to the giant relay contactor that connects the battery to the rest of the HV system. So pulling that loop disconnects the battery from the HV system by way of a relay.

 

[k3g]

The red cord does not carry 400v. It carries 12v to the giant relay contactor that connects the battery to the rest of the HV system. So pulling that loop disconnects the battery from the HV system by way of a relay.

Bingo. Sounds like a safety step to make sure the sudden drop of 12v doesn't kick the contactors closed to charge the 12v battery they're in the middle of unplugging.

 

[True Brit]

So, what is the actual strange replacement size for the battery? We can't be the only vehicle that uses this size. It has to have a designated name.

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