12V Questions

[SoCal Rob]

If your R1 has two batteries, one is the main battery, vbatt1, and the other is a back up, vbatt2. All of the ECU are powered by vbatt1, and some specific ECU are connected to vbatt2 and will switch if the voltage drops on vbatt1.

I have a question about your, "If..."

Does this mean that some (presumably newer) R1 vehicles are been produced with a single battery in place of the dual setup? I've seen speculation about a change but I don't recall seeing anything concrete.

Thank you!

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[EVLander]

I don't think that's what happens here. We've seen plenty of evidence that each of the batteries powers half of the car. Recalling one specific example from this forum, a single battery failed and the passenger side of the vehicle went down, including lights on that half of the vehicle.

Key word here is ECU. That is all I stated. Power feed for lights and other devices that do not pull power from the ECU are ran differently without redundancy. But I didn’t speak to that.

 

[Dark-Fx]

You can check my credentials if you like. I was an electronics engineer for Rivian for over three years. My role was to specific test and validate all of the ECUs on both the R1T and the R1S. I have intimate and comprehensive understanding of the ECU functions and circuitry, including power requirements, mechanical restraints and system design. My work there contributed to many design changes that resolved pre-production issues that are reflected in the vehicle today. You are more than welcome to call me out on anything, but you better have proof and data to support your claim.

How much of that work was done on a test bench with compensating power supplies?

Care to address why there were so many instances of people not being able to recover their dead vehicles by using the jumper cables at the back of the truck?

 

[EVLander]

I have a question about your, "If..."

Does this mean that some (presumably newer) R1 vehicles are been produced with a single battery in place of the dual setup? I've seen speculation about a change but I don't recall seeing anything concrete.

Thank you!

There was a lot of discussion with going to 1 battery. After I had left the company, I wasn’t sure if they actually went with the design change. So I made that statement as a blanket statement incase they went with the change.

 

[EVLander]

How much of that work was done on a test bench with compensating power supplies?

Care to address why there were so many instances of people not being able to recover their dead vehicles by using the jumper cables at the back of the truck?

I can’t comment to that as that was not my main area of expertise at Rivian, nor will I speculate. I have my ideas why that is but I won’t share company internals that are not public knowledge. Especially here since Rivian does monitor Rivian Forums.

 

[Dark-Fx]

I can’t comment to that as that was not my main area of expertise at Rivian, nor will I speculate. I have my ideas why that is but I won’t share company internals that are not public knowledge. Especially here since Rivian does monitor Rivian Forums.

About the response I expect. It's obvious you once worked for Rivian. Have a good day sir/maam.

 

[SoCal Rob]

There was a lot of discussion with going to 1 battery. After I had left the company, I wasn’t sure if they actually went with the design change. So I made that statement as a blanket statement incase they went with the change.

I appreciate the clarification. You made me stop being lazy and I just checked our R1S which was built in April. I can verify that it has 2 batteries.

Now, if only I could verify that I snapped the air intake cover back on properly.

Seriously, if any of your work made it into our recently-delivered Rivian, then thank you!

 

[EVLander]

I appreciate the clarification. You made me stop being lazy and I just checked our R1S which was built in April. I can verify that it has 2 batteries.

Now, if only I could verify that I snapped the air intake cover back on properly.

Seriously, if any of your work made it into our recently-delivered Rivian, then thank you!

Thanks! I appreciate the kind words. Congrats on your R1S!

 

[Visket]

You can check my credentials if you like. I was an electronics engineer for Rivian for over three years. My role was to specific test and validate all of the ECUs on both the R1T and the R1S. I have intimate and comprehensive understanding of the ECU functions and circuitry, including power requirements, mechanical restraints and system design. My work there contributed to many design changes that resolved pre-production issues that are reflected in the vehicle today. You are more than welcome to call me out on anything, but you better have proof and data to support your claim.

Now now... play nice kids. Please don't turn this into the Thread From Hell, as most other threads seem to invariably morph into. Let's stay on point, shall we?

Would you have the data points I'm looking for on the charging system?

Charging voltage range:
Charging Amperage range:
Charging kicks-in at: ___ volts
Charging stops at: ___ volts or when the battery only accepts ___ amps
Is the charge circuit wiring robust enough to handle the amount of current a LiFePo4 battery can absorb?

We have this data so far: Kicks-in at 12.09 volts. Runs for 100 minutes. Is that correct, or close to it?

Thanks for your insight so far - but numbers rule the day!

 

[EVLander]

Now now... play nice kids. Please don't turn this into the Thread From Hell, as most other threads seem to invariably morph into. Let's stay on point, shall we?

Would you have the data points I'm looking for on the charging system?

Charging voltage range:
Charging Amperage range:
Charging kicks-in at: ___ volts
Charging stops at: ___ volts or when the battery only accepts ___ amps
Is the charge circuit wiring robust enough to handle the amount of current a LiFePo4 battery can absorb?

We have this data so far: Kicks-in at 12.09 volts. Runs for 100 minutes. Is that correct, or close to it?

Thanks for your insight so far - but numbers rule the day!

Yes agree… let’s stay on subject.
I am also curious on the answers to the questions you posted. If you find it elsewhere, please update us. If I find anything, I’ll do the same.

 

[Electrified Outdoors]

There are rumors that R1 now has a single 12v battery. My March built R1T still has dual 12v.

 

[Visket]

So far, then, I wonder if:

1) Rivian has designed the charging so that one battery (the 40% DoD @ 12.09 volts) charges, while the *other* battery services the 12 volt electrical system. Kind of a leap-frog usage of the two batteries.

If this were the case, I think the two batteries would meter out to different voltages all the time. Does anyone have theirs taken apart where they could put both batteries on a volt meter? That could invalidate my theory real quick!

I would do this testing myself, but my wifee-poo won't let me touch anything electrical anymore - you know, after that one incident....

2) The charging voltage / amperage is *just enough* to charge an 18AH, sealed, deep cycle, lead-acid battery in a certain amount of time - perhaps no more than 100 minutes?

3) What could possibly deplete one of the batteries in 100 minutes while the other one is charging? Airing up. Plus airing up a friend on 40s. While pulling a trailer. At night. In the rain. And celebrating the trail ride with an ice cream... out of the freezer in the bed. While the wife and kids are listening to Rafi at volume 22. Maybe?

I'm not saying the Rivian works this way. Could just be "Hey - this truck is already going to cost and arm and a testicle. Let's buy the cheapest batteries we can source. Those? Sure!".

FWIW - my $0.02 worth.

 

[shap]

If your R1 has two batteries, one is the main battery, vbatt1, and the other is a back up, vbatt2. All of the ECU are powered by vbatt1, and some specific ECU are connected to vbatt2 and will switch if the voltage drops on vbatt1.

Thank you - it is a news to me, but I based my remarks on what was published many times in different threads, but obviously it was not a formal Rivian statement

Personally, I do not like a design that requires 2 batteries ...

 

[zigzagzap]

Thanks! I appreciate the kind words. Congrats on your R1S!

I’m in the same camp, and I appreciate your posts. I took delivery of my R1S on June 2, and one of my questions to the delivery guide was about the 12V batteries and issues reported.

The delivery guide proudly announced that the problems were software-related but that Rivian had resolved the issue but switching the configuration to a single battery and that my vehicle only had one battery. I had no reason to doubt her until now. I just checked and found TWO batteries. I can only speak about my interaction, but the level of misinformation from Rivian employees has been impressive.

 

[Craigins]

3) What could possibly deplete one of the batteries in 100 minutes while the other one is charging? Airing up. Plus airing up a friend on 40s. While pulling a trailer. At night. In the rain. And celebrating the trail ride with an ice cream... out of the freezer in the bed. While the wife and kids are listening to Rafi at volume 22. Maybe?

Running large system updates. Bricked a few vehicles, I had to take mine in to get the 12v replaced and firmware updated to run the 2023.6 update.

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