Brake Regen ?

[Electrified Outdoors]

Regen can be mapped to the brake pedal and be indistinguishable from using the friction pads. Rivian elected NOT to do that.

It's an excellent idea. OPD is one of the best features of an EV for me. I think though in order to make EV appealing to the masses this is the way to go. Then one can have the option in software to either have a traditional or OPD experience.

The only problem with blending that I'm aware of is that it has a much different feel. So the risk there is that folks may complain "the brake pedal feels funny".

I also liked how GM had the regen paddle. Lastly, if you have ever driven a Tesla the regen eases on more gradually and having that would be some improvement for those who don't like OPD.

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[f1racer328]

I prefer Rivian's method, and this is after driving a handful of other EVs too.

I don't want them to blend in brakes (unless its the brakes that come on with the hold feature when you're stopped)

I want to know what is going on with my vehicle, if I'm not decelerating fast enough, I will use the friction brakes. Energy management isn't a hard concept.... Just takes some practice.

 

[Jard]

Should I be able to change the Regen in All-Purpose mode?

2024.31.30 software

2025 Gen 2 DM R1S - there is no option to change the Regen level in the menu. It’s currently High and it’s too aggressive for me while driving on city / suburb streets. The transition from radar cruise to Regen for stoplights is way too abrupt.

Edit:
Solved this by switching into snow mode, and then the option for Low regen was there. Once I switched back into all purpose, the setting persisted. Not sure if related, but then the car asked me to do a software reset.

 

[saylormd]

Assuming you plan ahead and manage to avoid hydraulic braking, is high regen somehow more energy efficient than low regen? Or is it less efficient because with low regen you ease off on the One pedal sooner, thus giving the system more time and distance to capture the same momentum energy? Which setting does Rivian use for EPA tests?

 

[mkhuffman]

Assuming you plan ahead and manage to avoid hydraulic braking, is high regen somehow more energy efficient than low regen? Or is it less efficient because with low regen you ease off on the One pedal sooner, thus giving the system more time and distance to capture the same momentum energy? Which setting does Rivian use for EPA tests?

This is something that I am sure many will disagree about. And I have my own theory that is practically impossible to prove. Not impossible, but testing actual regen efficiency is very hard.

Anyway, my theory is high regen is always more efficient than low regen, even if you avoid using the friction brakes, because you waste less energy due to aerodynamic losses. Air resistance will slow the car as you decelerate, reducing how much you can regain with regen. If you use high regen, the vehicle will slow more quickly and air resistance will be a smaller impact (relatively), returning more energy from the deceleration to the battery.

It's weak, I know. The only data point I have to support it is when I got my worst efficiency ever when I switched to low regen (in my Mach-e, so also less relevant to your question).

There are those who believe ICEV hypermiling techniques like coasting is more efficient in a BEV also, but I am very skeptical that is true based on my own experience. I tried that and got horrible efficiency. It was much better with high regen.

 

[beatle]

Assuming you plan ahead and manage to avoid hydraulic braking, is high regen somehow more energy efficient than low regen? Or is it less efficient because with low regen you ease off on the One pedal sooner, thus giving the system more time and distance to capture the same momentum energy? Which setting does Rivian use for EPA tests?

When I had each of my Model Ses, the regen was kind of weak and I found myself using the friction brakes more often. You can't always use regen 100% of the time if it's weak and you suddenly need to slow down. There are always emergencies where no regen will be strong enough, but since the Rivian's regen is so strong, those situations are much less frequent now. I think any benefit to be gained by low regen would be negated by the additional times you have to use the friction brakes and convert that kinetic energy into wasted heat.

 

[moosetags]

I have become a big fan of brake regen on my R1T. I always drive in the "HIGH" brake regen position. When we took delivery of Opal (our R1T) at the Factory in Normal about a year and a half ago, the delivery tech told us to start with the low regen to ease into the OPD feature. We found it a little unnerving at first, but quickly became comfort able with it. Within our first day of ownership we moved up to the high regen level, and the rest is history. At first, I had some concerns about switching between the Rivian and our ICE truck. We found that our concerns were unwarranted, and the transition is seamless. Our ICE truck is a Silverado Duramax Diesel. Diesel trucks have a certain amount of compression backpressure which reacts like a small amount of brake regen. When the Diesel truck's exhaust brake function is activated, it has even a greater brake regen type feel. Possibly, our extensive diesel experience has made brake regen and OPD more comfortable.

Opal's high regen OPD has become our favorite feature. We rarely touch Opal's brake pedal. We feel that OPD has made us better drivers as it requires that we pay more attention to our driving. If Opal's regen were even stronger, that would be fine with us.

Brian

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