Sponsored

Mitigating Limitations of Regenerative Braking?

Sgt Beavis

Well-Known Member
First Name
Rick
Joined
Sep 28, 2021
Threads
79
Messages
2,119
Reaction score
4,520
Location
Colorado
Vehicles
2022 Rivian R1T, 2021 Jeep Wrangler Rubicon
Occupation
Overpaid Computer Nerd
Clubs
 
Just curious, what road are you coming down? It looks like Lee Hill Dr or Sunshine Canyon. I haven't come down Sunshine yet but I've driven Lee Hill both ways and have never touched my brake pedal.

Let me know and I'll try driving it this weekend and let you know what happens with my R1T. Feel free to PM me if you want to keep it private.
Sponsored

 
OP
OP
Phrogz

Phrogz

Well-Known Member
First Name
Gavin
Joined
Apr 28, 2021
Threads
23
Messages
115
Reaction score
173
Location
Boulder, CO
Website
phrogz.net
Vehicles
'66 Ford Jeep, '01 SLK 32AMG, '10 Wrangler, '19 Q7
Occupation
Autonomous Driving Software
I’ve seen this routinely on local steep descents. My guess is that it’s a heat issue. I’m highly confident it has nothing to do with the battery’s charge level as I’ve had it at 30 to 70%.
The incongruous thing is that on a 21°F morning it behaved roughly the same, except that a snowflake icon appeared next to the regenerative braking curve and instead of “Regenerative braking reduced. Use brake to slow down” the message said “Acceleration and regenerative braking are reduced until the battery warms up”.
 
OP
OP
Phrogz

Phrogz

Well-Known Member
First Name
Gavin
Joined
Apr 28, 2021
Threads
23
Messages
115
Reaction score
173
Location
Boulder, CO
Website
phrogz.net
Vehicles
'66 Ford Jeep, '01 SLK 32AMG, '10 Wrangler, '19 Q7
Occupation
Autonomous Driving Software
Just curious, what road are you coming down? It looks like Lee Hill Dr or Sunshine Canyon. I haven't come down Sunshine yet but I've driven Lee Hill both ways and have never touched my brake pedal
This is the last mile of Magnolia.
 
OP
OP
Phrogz

Phrogz

Well-Known Member
First Name
Gavin
Joined
Apr 28, 2021
Threads
23
Messages
115
Reaction score
173
Location
Boulder, CO
Website
phrogz.net
Vehicles
'66 Ford Jeep, '01 SLK 32AMG, '10 Wrangler, '19 Q7
Occupation
Autonomous Driving Software
I video’d it yesterday for those curious. I’d climbed in the truck a minute prior at 43°F, drove a few hundred feet, stopped to take out the garbage, and then started videoing. The reduced braking starts around 0:54; I repeatedly had to use the brake pedal for safety.

 

Zorg

Well-Known Member
Joined
Nov 1, 2022
Threads
9
Messages
1,005
Reaction score
1,227
Location
SF bay area
Vehicles
Model X
I assumed that regen goes through the main inverter (motors are AC, pack is DC). At least, that's how it worked on my RC cars. :)

On my Tesla (R1T should arrive soon), regen peaks at 50KW, so that's definitely not going through on board charger.
 

Sponsored

SeaGeo

Well-Known Member
First Name
Brice
Joined
Jan 12, 2021
Threads
50
Messages
5,673
Reaction score
10,212
Location
Seattle
Vehicles
Xc60 T8
Occupation
Engineer
The incongruous thing is that on a 21°F morning it behaved roughly the same, except that a snowflake icon appeared next to the regenerative braking curve and instead of “Regenerative braking reduced. Use brake to slow down” the message said “Acceleration and regenerative braking are reduced until the battery warms up”.
The inconsistency is the thing the confused me too. I was able to "prompt" the snowflake last night, which was a first.
 

Sgt Beavis

Well-Known Member
First Name
Rick
Joined
Sep 28, 2021
Threads
79
Messages
2,119
Reaction score
4,520
Location
Colorado
Vehicles
2022 Rivian R1T, 2021 Jeep Wrangler Rubicon
Occupation
Overpaid Computer Nerd
Clubs
 
This is the last mile of Magnolia.
Oh, I know that road. Yea, I've driven up a few times but haven't come down it with the R1T. Last time I did it was in my Raptor and I could smell my brakes afterwards.
 

McRat

Well-Known Member
Joined
Nov 7, 2020
Threads
6
Messages
100
Reaction score
150
Location
California
Vehicles
'22 R1T, MXLR+, 2xVolts, MC's
Occupation
Tinkerer
For those in SoCal, you can see this happen regularly on the way down from Big Bear.
My I-Pace didn't do it, nor does my Model X.
It doesn't matter if you are 2wd (Conserve) or 4wd Sport, All-Purpose, Snow.
I charge to 85% for the trips (round trip consumption 50-55% SOC).

I'm thinking if we can get a datalogger and read the battery temp and inverter temp and coolant temp, we might be able to fit a bigger radiator or fan to increase airflow and cool the system faster.

It should not be happening.
Sponsored

 
 








Top