Regeneration Concerns

[Dark-Fx]

I agree with the blending of the brakes. Yet another example of "please just copy Tesla".

Except Tesla hasn't been doing blended one-pedal regen for very long. Polestar has been doing it longer.

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[teartags]

YES we do. Set your traction control to Reduced if you want front and back to regen on the dual.

Huh. What's the reasoning behind that?
Truthfully, that's the one setting I haven't really messed with very much.

 

[teartags]

Huh. What's the reasoning behind that?
Truthfully, that's the one setting I haven't really messed with very much.

...and by "Traction Control" I assume you mean "Stability"?

 

[VSG]

What I don't get is why they don't blend the friction brakes to simulate regen when normal regen is limited.

I agree that blended braking might produce a more satisfying customer experience.

But remember even Tesla, master of all things EV, just introduced that feature last year - for the prior 10 years even Tesla hadn't been doing that. A lot of these "blended braking" comments seem to portray that this was an obvious thing that they should have been doing from the beginning. But if it was so obvious why did it take Tesla 10 years?

Rivian is still a new company and is iterating towards a better vehicle, and we have seen over the past year that they have made huge improvements to their platform via OTA updates. That is one of Rivian's strengths - that it CAN make these improvements, and that the vehicle does NOT have to be set in stone before it is shipped. At some point they had to freeze the feature set and make that work. And they did. Now that Rivian has successfully shipped the R1 they can work on making it better.

Rivian made a bunch of decisions along the way about what to prioritize and what can be left for future improvements. You many not agree with their choices or their priorities, but I think they have proven that they can make the choices necessary to survive as a company. Look at all the other EV startup that have failed or are about to fail because they were not able to navigate their way to success against a highly-entrenched car industry. Rivian is doing something that very few companies have managed to do.

 

[MrMusAddict]

I agree that blended braking might produce a more satisfying customer experience.

But remember even Tesla, master of all things EV, just introduced that feature last year - for the prior 10 years even Tesla hadn't been doing that. A lot of these "blended braking" comments seem to portray that this was an obvious thing that they should have been doing from the beginning. But if it was so obvious why did it take Tesla 10 years?

Rivian is still a new company and is iterating towards a better vehicle, and we have seen over the past year that they have made huge improvements to their platform via OTA updates. That is one of Rivian's strengths - that it CAN make these improvements, and that the vehicle does NOT have to be set in stone before it is shipped. At some point they had to freeze the feature set and make that work. And they did. Now that Rivian has successfully shipped the R1 they can work on making it better.

Rivian made a bunch of decisions along the way about what to prioritize and what can be left for future improvements. You many not agree with their choices or their priorities, but I think they have proven that they can make the choices necessary to survive as a company. Look at all the other EV startup that have failed or are about to fail because they were not able to navigate their way to success against a highly-entrenched car industry. Rivian is doing something that very few companies have managed to do.

I think you "turned up to 11" a misperceived tone from my comment. To be clear, I'm in no way trying to imply that the lack of blended brakes during limited regen is a sign of company failure, incompetence, or non-competitiveness. The lack of the feature is manageable, just unnerving. Especially when limited regen happens for the first time, and you don't know why you're accelerating, and you don't recognize the chime, and the text notification only stays on the dashboard for 3 seconds and you don't have time to read it because your attention is on the road trying not to crash.

 

[kylealden]

The vehicle is not speeding up - the braking was reduced just as if you had eased up on the brake in your ICE vehicle while heading down the hill. You FELT this and it SEEMED like you sped up, but I doubt you changed speed by more than 1 mph before you reacted.

The fix here is pretty straightforward: Enable blended braking to maintain a constant rate of perceived "engine braking" regardless of the state of regen.

I don't personally like it (and it has efficiency downsides because any time you're applying mechanical brakes, you're theoretically wasting energy, so making that unpredictable is "bad" for efficiency); but it's good for predictability, which is good for safety. And it could likely be done via an OTA update (and as an option, like Tesla.)

(Which is another reason I don't like it: Now you've added configuration complexity and outsourced the question of the "right" configuration to your customer.)

 

[VSG]

I think you "turned up to 11" a misperceived tone from my comment. To be clear, I'm in no way trying to imply that the lack of blended brakes during limited regen is a sign of company failure, incompetence, or non-competitiveness.

That part of my comment wasn't specifically aimed at you, although that wasn't clear because I did quote your post as starting point for my comments. In my mind I was thinking more about addressing the dozens of other recurring threads over the past few years which have taken that tone every time this issue with regenerative braking arises.

Regardless, I do agree with you that blended braking would be a nice improvement. I personally consider it a bonus feature as opposed to a must-have safety issue.

 

[racekarl]

The Rivian already has blended braking in the sense that it can engage the service brakes without the driver pressing the brake pedal - you can hear and feel the service brakes engage as you come to a stop and the truck shifts to hold. I imagine it could potentially be just a software change to have the service brakes engage under additional scenarios.

Separately, I don't see how the number or power of the motors would make a difference. If the same mass vehicle is changing speed at the same rate, I would think the energy to the battery is the same no matter how many motors are sharing the task of converting kinetic energy to potential energy.

 

[AlcesBull]

i agree that they need to provide more early warning. its not helpful or useful if the warning and the lack of regen happen at the same time and i could see someone getting rear-ended due to this. for me, its always happened when going downhill, the temps were in the 30s/40s and the battery was not "warm enough" (id say the battery temp was roughly below 45 degrees F).

Does this tend to change if the battery is warmer (e.g. you've been on the road for a long time before hitting a big descent?)?

 

[Dark-Fx]

...and by "Traction Control" I assume you mean "Stability"?

Yes. Guessing Rivian chose to do this because the reduced setting could result in locking up just the front tires otherwise. In a turn that means your vehicle will stop turning and head straight for the side of the road.

I think for normal operation they would prefer limiting the amount of times the rear motors get engaged. It's designed to do it under power or Regen but it's still additional wear.

 

[runningdenver]

I've been an EV driver for 10 years and love my new "max pack" R1T. However, I have serious concerns about the break regeneration system. Specifically, the fact that regeneration is decreased so frequently and so suddenly.

For example, on a drive down the mountains from Summit County to Denver last weekend, my R1T had "decreased regeneration" for almost half the drive. It seems like a huge waste! And when I was doing 70 mph down a 7% grade and the truck sped up out of the blue, while simultaneously beeping a warning at me that the brake regeneration was decreased, it was actually dangerous.

There's also reduced regeneration basically any time the battery is over 80%. For comparison, I put 100,000 miles on a Chevy Bolt and never had any of these issues. There was decreased regeneration when the battery was at 100%, but it would be back to normal at 99% and never decrease again...even on the entire drive down I-70 from Summit County. It would gain miles and miles of range...many more than the R1T. Does Chevy just have a better battery? Better technology of some sort? Why can't Rivian accomplish with the R1T what Chevy has accomplished with the Bolt?

I'd love to see much better overall regeneration...and at the very least, a 2-second warning before decreased regeneration happens so it's not so jarring. I actually felt out of control when the truck sped up without warning (or simultaneous warning, which feels the same when driving).

Anyone have similar experiences? Any idea what can be done about it? Maybe an OTA update of some sort?

Hmmm, this is a little disappointing if it's a common experience.. I drive I-70 all the time, will pick up my R1S tomorrow. I'll be heading to Leadville and back next week, so guess I'll find out. I'll post if I hit the same issue.

 

[rhumbliner]

Can you point to where Rivian specifically said that?

Here’s the previous thread: Regen Disabled .

I disagree with the “blended brake” approach. I’d rather they fix their battery management system. As @Cosmacelf pointed out, having a single cooling plate just doesn’t cut it.

 

[s4wrxttcs]

What I dislike about Rivians Regen is not just the low state of charge limitation, but how inconsistent it is.

Like the other day everything was fine with no limited regen, but then I went down a moderate hill and suddenly all the regen stopped. Just suddenly sped up and gave me the warning that said there was no available regen.

No explanation as to why.

I didn't see anything that stuck out on the battery/motor temp gauge. I meant to do a screen capture, but couldn't remember in the moment how to do the screen capture.

The other annoyance is it doesn't always tell you ahead of time that the regen is limited. Like the regen will show fine without any marks, but then suddenly it changes while going down a hill.

I expect regen to be limited if I'm above 90% SOC or if the battery is cold. Aside from those two things I don't expect regen to be limited unless its a fairly big edge case. Like some massive hills.

But, that's not the case with the Rivian. The regen finds any excuse it can to stop. Haha. Like if its at 86% then its reduced.

 

[Thedude]

If only there was a gauge in the dash that showed a realtime constant readout of power available, power applied, regen available and regen applied.

 

[s4wrxttcs]

If only there was a gauge in the dash that showed a realtime constant readout of power available, power applied, regen available and regen applied.

I can't tell if this is being sarcastic with the assumption that the gauge already gives this.

Or if this post is about wanting a better gauge.

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