EPA data shows Rivians more efficient than Cybertruck, even with larger wheels and batteries

[DuoRivians]

Not the OP. This is a bit over my head. Perhaps someone more experienced can chime in please.

https://www.reddit.com/r/teslamotors/s/GaiHp0lix5

Of course, wheel + tires would affect these figures

Edit: The OP of this reddit post says the 20” R1T gets ~5% higher Wh/mi versus the 22”

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[COdogman]

@Dark-Fx reads those docs for fun. He can decipher for us Rubes.

 

[Dark-Fx]

R1 with Enduro is quite a bit more efficient than the Cybertruck. Gap seems to widen with the faster tests as well, which tracks with Tesla historically being further from EPA rating during highway tests when compared to other manufacturers.

Tesla's correction factor looks quite optimistic, especially for the dual AWD model.

 

[DuoRivians]

R1 with Enduro is quite a bit more efficient than the Cybertruck. Gap seems to widen with the faster tests as well, which tracks with Tesla historically being further from EPA rating during highway tests when compared to other manufacturers.

Tesla's correction factor looks quite optimistic, especially for the dual AWD model.

 

[DuoRivians]

Energy density at *pack* level (not cell)

 

[HaveBlue]

6 mi/kWh at 30mph and 4 at 50! We driving to fast...

 

[KootenayEV]

6 mi/kWh at 30mph and 4 at 50! We driving to fast...

I once drove my 2014 Leaf a constant 40km/h and achieved 200km of range (over 10km/kWh)… I don’t want to take the time to try the equivalent in my R1T lol.

edit: turns out it was 182km, but the point stands. Dug up this almost 10 year old post on my blog… my how things have changed! http://kootenayevfamily.ca/trip-report-kelowna-and-back-part-3-and-the-last/

 

[docwhiz]

Energy density at *pack* level (not cell)

Interesting that the Tesla 4680 cells are lower density than 18650

 

[usofrob]

The reddit post was updated to show the R1T Large 20" with worse efficiency than CT at 50, but about the same at 70 mph. With the CT battery being smaller, maybe on a cold day when the CT is using it's heat pump and the R1T is using it's heater, the total range would be more similar.

I wonder how the efficiency of the 21" max pack might relate to the CT with Range Extender.
R1T Dual Max 21" : 233 wh/mile
CT Range Extender : 278 wh/mile (assume about the same as the 3 motor, but with the added weight it might be worse)
Battery:
R1T : 149 kWh
CT : 173 kWh
Max Range:
R1T : 149000/233 = 640 miles
CT : 173000/278 = 622 miles

Hehe, hmmm, that range seems pretty optimistic But also about the same.

To get comparable ranges, it seems like in the winter with the R1T Dual with Large Pack on 20" AT tires, and the CT on it's 20" tires, the highway range may be similar.

For the CT Range Extender, the range might be similar to the R1T on 21" with Max Pack.

At 80-90 mph, the R1T is likely to pull a larger lead.

*** These numbers are clearly not representative of real world range directly. I think this is mostly just comparing the motor and aero efficiencies. Other electrical load to run the computers and other accessories (HVAC) are likely not included in the EPA's estimates.

 

[Dark-Fx]

*** These numbers are clearly not representative of real world range directly. I think this is mostly just comparing the motor and aero efficiencies. Other electrical load to run the computers and other accessories (HVAC) are likely not included in the EPA's estimates.

They actualy are, that's what the adjustment factor is supposed to represent.

 

[DuoRivians]

They actualy are, that's what the adjustment factor is supposed to represent.

R1T uses 0.7, whereas Cybertruck uses 0.8.

That discrepancy seems quite high, even after accounting for heat pump or 48V wiring

 

[usofrob]

They actualy are, that's what the adjustment factor is supposed to represent.

So, take those numbers then multiply by their respective adjustment factors?

Edited to add from the OP on reddit:
"The coastdown test represents the power lost against the forces of gearbox friction, aerodynamic drag and rolling resistance while decelerating in "neutral" on a flat road. Put another way, it's the bare minimum power required to maintain a certain speed on the same flat road. It doesn't account for electrical losses in the battery or motor inefficiencies, which can add another 5-10% to overall driving consumption."

 

[usofrob]

Here is the full graph up to 80 mph (also from reddit):


The CT scales more similarly to the Silverado than the Rivian. But, surprisingly (to me), the Lightning scales even worse. But maybe it's actually a bigger truck. Red is CT, the bottom three are Rivian.

 

[Dark-Fx]

So, take those numbers then multiply by their respective adjustment factors?

This is one of the typical spreadsheets the EPA uses for all the label calculations https://www.epa.gov/system/files/ot...3-generic-ev-label-calculator-2022-01-19.xlsm

Unfortunately since it's based off an SAE test (J1634) the specification is paywalled so I can't link it.

Manufacturers can choose a 2-cycle test which includes the default 0.7 adjustment factor, or can do a 5 cycle test to fully calculate it out. 5 cycle adds a test that is for more aggressive driving, one that's with A/C on in a 95°F lab, and one that's done at 20°F with heat on.

 

[DuoRivians]

Here is the full graph up to 80 mph (also from reddit):


The CT scales more similarly to the Silverado than the Rivian. But, surprisingly (to me), the Lightning scales even worse. But maybe it's actually a bigger truck. Red is CT, the bottom three are Rivian.

One of the bigger factors is R1T’s drag coefficient of 0.30 versus Cybertruck’s 0.34. Which magnifies the difference effect with more speed

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