12 volt inspection

[C.R. Rivian]

Just had a call from Rivian to schedule a mobile visit to check my 12 volt system.

Might ask service if, at my expense, they could swap out the lead acid for an Li-ion battery when they do this.

Would appreciate some thoughts/feedback.

Thinking about these:

12V Lithium Battery 2-Pack for Rivian R1S / R1T | ohmmu.com

Thanks!

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[Marchin_MTB]

Not sure about swapping but I went in to have my 12v replaced this morning. It was a “courtesy service” initiated by Rivian (they called).

edited to add that service confirmed some 12V were being drained as a result of 2023.6 and that remote diagnostics indicated my voltage dropped below some threshold. I had not noticed anything.

 

[Ralph]

Just had a call from Rivian to schedule a mobile visit to check my 12 volt system.

Might ask service if, at my expense, they could swap out the lead acid for an Li-ion battery when they do this.

Would appreciate some thoughts/feedback.

Thinking about these:

12V Lithium Battery 2-Pack for Rivian R1S / R1T | ohmmu.com

Thanks!

Last I heard, they wouldn't even install any tires/wheels that were not stock.

 

[C.R. Rivian]

Last I heard, they wouldn't even install any tires/wheels that were not stock.

I've asked my guide to look into it. She's usually pretty good. Will post any information I get.

 

[TheLTrain]

Not sure about swapping but I went in to have my 12v replaced this morning. It was a “courtesy service” initiated by Rivian (they called).

edited to add that service confirmed some 12V were being drained as a result of 2023.6 and that remote diagnostics indicated my voltage dropped below some threshold. I had not noticed anything.

In the same boat. They just said I was flagged by remote diagnostics but I haven’t noticed anything on my end. It’s nice to know that Rivian is watching over us ?

 

[k3g]

They're likely going to not want to swap for a LiPo. They'll cite compatability or liability reasons, but the underlying reason is that it wouldn't work with the car as it's built. Here's how it works:

First, LVM:
The R1 has a few versions of 'on', and one of them is called Low Voltage Maintenance (LVM). The way LVM works, is one of the ECUs watches the voltage of the 12v system. Because they're lead acid, that slowly goes down over time. Things like proximity detection are powered by the 12v system. When the 12v batteries get to a low state of charge (SoC), the truck wakes up the High Voltage battery ECU, and turns on a big ol' buck converter to bring the 400v down to 12v. All that machinery costs some power to turn on, but the 12v charging is decently efficient. Once the 12v lead battery gets up to a healthy voltage, LVM ends, and the truck goes back to sleep.

So if you go to a LiFePO4 battery (not LiPo because reasons), now your 12v system is relatively flat. It doesn't slowly lower nearly to the same magnitude as lead acid does.

Why is changing only the battery not the best idea?
The failure mode here will leave you stranded and needing a tow. If your fancy new lithium's battery SoC gets real low, to where a strong load (like closing HV contacts to go drive) will draw too much, the battery's BMS will cut output power. So, because the LiFePO4 battery's voltage stays flat, it slowly discharged overnight as you're parked without triggering LVM. Now in the morning you go to drive, and the 12v battery doesn't have the chooch to turn things on. Bummer.

When everything is working well (high 12v SoC, driving the R1 often, or storing it on a charger at all times) your shiny new LiFePO4 battery would probably be okay, but it would be a very critical failure point to introduce to the truck.

 

[C.R. Rivian]

They're likely going to not want to swap for a LiPo. They'll cite compatability or liability reasons, but the underlying reason is that it wouldn't work with the car as it's built. Here's how it works:

First, LVM:
The R1 has a few versions of 'on', and one of them is called Low Voltage Maintenance (LVM). The way LVM works, is one of the ECUs watches the voltage of the 12v system. Because they're lead acid, that slowly goes down over time. Things like proximity detection are powered by the 12v system. When the 12v batteries get to a low state of charge (SoC), the truck wakes up the High Voltage battery ECU, and turns on a big ol' buck converter to bring the 400v down to 12v. All that machinery costs some power to turn on, but the 12v charging is decently efficient. Once the 12v lead battery gets up to a healthy voltage, LVM ends, and the truck goes back to sleep.

So if you go to a LiFePO4 battery (not LiPo because reasons), now your 12v system is relatively flat. It doesn't slowly lower nearly to the same magnitude as lead acid does.

Why is changing only the battery not the best idea?
The failure mode here will leave you stranded and needing a tow. If your fancy new lithium's battery SoC gets real low, to where a strong load (like closing HV contacts to go drive) will draw too much, the battery's BMS will cut output power. So, because the LiFePO4 battery's voltage stays flat, it slowly discharged overnight as you're parked without triggering LVM. Now in the morning you go to drive, and the 12v battery doesn't have the chooch to turn things on. Bummer.

When everything is working well (high 12v SoC, driving the R1 often, or storing it on a charger at all times) your shiny new LiFePO4 battery would probably be okay, but it would be a very critical failure point to introduce to the truck.

Great explanation, thanks! So, basically, Rivian would need to do an OTA update that included a toggle for going with a different battery configuration. Tesla must have done something along those lines when they went Li-ion.

Too bad, because lead acid batteries do fail and often without warning. Wonder if the Rivian diagnostics could catch a failing lead acid. One of the pluses to the ohmmu is their app:

<<Ohmmu Bluetooth App

Get valuable diagnostic and lifecycle information, State of Charge (SOC), and more from these Bluetooth-enabled batteries with the Ohmmu App.>>

Thanks, again.

 

[NY_Rob]

100% guarantee you will get the same lead-acid batteries that came with the truck. The Rivian Service Center is not some privately owned 3rd party shop that can do whatever they want or whatever the customer requests. As mentioned above, they won't even set the tire size if you purchased non-OEM tires.

 

[JayinNJ]

Just had a call from Rivian to schedule a mobile visit to check my 12 volt system.

Might ask service if, at my expense, they could swap out the lead acid for an Li-ion battery when they do this.

Would appreciate some thoughts/feedback.

Thinking about these:

12V Lithium Battery 2-Pack for Rivian R1S / R1T | ohmmu.com

Thanks!

No way they are going to swap out any parts that aren't OEM. Just like if you bought a new aftermarket bumper.

 

[Zoidz]

Great explanation, thanks! So, basically, Rivian would need to do an OTA update that included a toggle for going with a different battery configuration. Tesla must have done something along those lines when they went Li-ion.

Too bad, because lead acid batteries do fail and often without warning. Wonder if the Rivian diagnostics could catch a failing lead acid. One of the pluses to the ohmmu is their app:

<<Ohmmu Bluetooth App

Get valuable diagnostic and lifecycle information, State of Charge (SOC), and more from these Bluetooth-enabled batteries with the Ohmmu App.>>

Thanks, again.

LiFePO4 batteries have a different charging curve profile than a lead acid battery. The OTA would also need to update the charging parameters.

 

[BoltEVowner]

Got the "service 12 volt battery system" warning message on the latest software for Halloween on my 2022 R1T.

Multiple software resets and sleep cycles haven't fixed. Contacted Rivian service, waiting for a response, but afraid to drive it out of the garage for fear of being stranded.

Wondering if the newer software updates are giving this warning message to PREVENT us getting stranded whereas earlier there was no warning? Anybody know?

And watched the Ohhmu lithium ion battery replacement video, wondering if anyone has done this already, understanding Rivian probably wouldn't support it and might void the warranty, and might not work correctly without a Rivian software update supporting this type replacement.

From what I am reading, this seems to be a WAY too common problem for an electric vehicle...not just Rivian!

 

[BoltEVowner]

Rivian mobile service scheduled next week. For now, keeping it plugged in, parked in garage. Only losing about 2 weeks of use of my R1T. Hoping they can remedy this problem, as lead acid batteries should last 4 years, not a year and a half! Ultimate solution is lithium ion 12 volt batteries, and give us a monitoring system.

 

[BoltEVowner]

R1T eventually bricked in garage, had to jump primary and secondary 12 volt battery to get it into gear to remove from garage, then back into garage to get proper "6 feet" clearance for the mobile Rivian service tech that came the next day, and replaced both the batteries. Took less than an hour, and all back to normal now.

 

[SoCal Rob]

R1T eventually bricked in garage, had to jump primary and secondary 12 volt battery to get it into gear to remove from garage, then back into garage to get proper "6 feet" clearance for the mobile Rivian service tech that came the next day, and replaced both the batteries. Took less than an hour, and all back to normal now.

As annoying as the issue is, it’s encouraging to read that you were able to resuscitate your R1T so that it could move under its own power again. I seem to recall that some others couldn’t in the past.

Did you have two sets of jump leads with one set to each battery simultaneously or did you charge one battery and then the other? Is it safe to assume that you have to access the batteries directly via the frunk?

 

[BoltEVowner]

Access to primary battery jump is via the two wires pulled out of the round plastic cover to the right of the tow hitch. I charged this up, then connected to a 12 volt lithium ion battery I just happened to have.

Unable to get into gear, so went through the frunk access for the secondary battery (measured 2.6 volts initially), charged it to 13 volts with my charger.

Then was able to make the vehicle drive able to get out of garage

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