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Discussion Starter · #1 ·
I read (with great interest) the discussions regarding towing on a downhill and behavior on icy roads.
What I'm wondering is if Rivian has the equivalent of 'downshifting'.
I don't think regenerative braking is quite the answer.
Example: When I'm in Colorado with my Land Rover LR4, and I'm navigating a steep curving downhill, that runs for several miles, I can switch my 8 speed auto trans into manual, and using paddle shifters, choose my 'downshift' gear.
This is important, since the grade and curves change very often, and, while watching my tach and speed, I can choose the right gear. Doing this almost obviates using the brakes. In the meantime, I watch all the red brake lights of vehicles in front of me; including the smoking brakes of large trucks.

So, question is, does anyone know if I can do something similar in a Rivian. Can I dynamically choose the amount of regenerative braking to apply (that is, without going through a menu drill-down on a computer display).
 

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On the Rivian, you have two levels of regen, standard and (what should be called) Ludicrous. You can only get to this setting from the Drive Mode screen.
However, you can modulate the effective amount of regen in any mode using the accelerator…the more you back off on the pedal, the more regen. You have to be careful depending on your SOC, though…if the battery is near or at 100% SOC (which could easily happen at the start of a tow mission), regen strength can be anything from limited to non-existent. That’s not something you want to find out for the first time at the top of a long downhill pulling a 7.5K dump trailer of stone.
What I don’t know is if Tow Mode somehow augments stooping ability in this scenario.
 

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I fully agree with others with some exceptions. In moderate to warm weather regen is superior to down shifting (engine braking), it is much more powerful then even a large V8. On snow/ice it is not as it can be too aggressive, I changed to my winter tires yesterday on the Tesla (it looks like our 3 days of fall is over time for full blown winter…) when I do the swap I put them in regen low and leave it that way until May when I remove my winter tires. Also cold, below ~50F you will have limited regen until the batteries warm from driving it, below ~30F you will have almost no regen. So if you were to live/park/camp near the top of a downgrade then start out with a cold truck regen wouldn’t be an option probably for the first 5-10 miles.

in summery, some conditions regen is better other conditions it is worse, but the only option other then friction brakes in an EV.
 

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The regen has a limit…not sure if it’s a heat related…I’ve had the regen disengage on a steep mountain downhill near my home multiple times. The energy arc displays hatched zone, and the display announces the regen is disengaged. This is without a trailer, so you might expect this earlier/often towing any significant weight downhill
 

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Discussion Starter · #6 · (Edited)
Interesting replies; thank you.
It would be interesting to know:
1. The effect on regenerative braking for SOC between 95 and 100%
2. How finely (and dynamically) regen braking can be adjusted.
3. Is regen braking really meant to be an equivalent to downshifting an ICE transmission.
(It doesn't sound like it is designed as an equivalent if it disconnects under certain conditions).

Does anyone know how to ask Rivian these questions?

Thanks
 

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Interesting replies; thank you.
It would be interesting to know:
1. The effect on regenerative braking for SOC between 95 and 100%
2. How finely (and dynamically) regen braking can be adjusted.
3. Is regen braking really meant to be an equivalent to downshifting an ICE transmission.
(It doesn't sound like it is designed as an equivalent if it disconnects under certain conditions).

Does anyone know how to ask Rivian these questions?

Thanks
1) it reduces regen near the battery limit. The truck will tell you it’s not avail…charge to 100% and you’ll see.
2) idk. The truck gives you two options…you’ll want high to get max range…you just have to get accustom to the deceleration
3)no…it isn’t…it’s to extend your range.
 

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Interesting replies; thank you.
It would be interesting to know:
1. The effect on regenerative braking for SOC between 95 and 100%
2. How finely (and dynamically) regen braking can be adjusted.
3. Is regen braking really meant to be an equivalent to downshifting an ICE transmission.
(It doesn't sound like it is designed as an equivalent if it disconnects under certain conditions).

Does anyone know how to ask Rivian these questions?

Thanks
I can tell you from 8 years and ~90k miles in EVs.
1# pretty much none, I have to get to 90-95% before regen gets to full power.

2# very finely with the accelerator but it depends on your right foot modulation. A little more pedal a little less regen. On a long downhill I think the cruse control does a great job at maintain speed through regen, much better job then I could ever do. And totally different than ICEs.

3# What you need to understand is an ice engine brakes due to engine compression. EVs have no compression so downhill they will just freewheel it, the only way to engine brake is via Regen.
 
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