Cybertruck Energy Consumption at Slow Speeds

bfrench

Member
First Name
Bill
Joined
Mar 9, 2021
Messages
21
Reaction score
47
Location
Utah
Vehicles
CyberTruck (tri-motor on order)
Occupation
Software
Country flag
Given a fully charged tri-motor Cybertruck, how many miles might it be able travel on level ground at 6mph?

I'm no energy or math wizard but I'll bet there's a pretty good estimate that could be made with some assumptions that obviously involve the motors. Anyone have an approach I should play with?
Advertisement

 

Crissa

Well-known member
First Name
Crissa
Joined
Jul 8, 2020
Messages
5,976
Reaction score
7,855
Location
Santa Cruz
Vehicles
2014 Zero S, 2013 Mazda 3
Country flag
We would need to know the Wh/mi for 6mph. Things like rolling resistance and surface variation would dominate the calculation.

What are you doing, using it as the base of a mutant vehicle?

-Crissa
 

ajdelange

Well-known member
First Name
A. J.
Joined
Dec 8, 2019
Messages
2,953
Reaction score
3,145
Location
Virginia/Quebec
Vehicles
Tesla X LR+, Lexus SUV, Toyota SR5, Toyota Landcruiser
Occupation
EE (Retired)
Country flag
I guess I'd WAG it by noting that broad as the high efficiency contours on an IM's torqe/speed plot are they do fall off at the edges so there will be some loss at very slow speed. Assuming that 500 mi EPA range is delivered I guess I'd assume 10% efficiency loss at low speed and offer 450 mi. The motor efficiency loss would be offset to some extent by reduction in inverter loss (low current at low speed), low slip loss and low rolling resistance loss.

Of course these are new motors so perhaps their high efficiency peaks are even broader. I wouldn't call this a good estimate because we have no info on the motor to base it on.
 

CyberGus

Well-known member
First Name
Gus
Joined
May 22, 2021
Messages
308
Reaction score
838
Location
Austin, TX
Vehicles
1981 DeLorean, 2022 Cybertruck
Occupation
IT Specialist
Country flag
That makes no sense that it would lose range when it doesn't have air resistance to speak of.

-Crissa
True, but there is overhead to consider: onboard computer, thermal management, etc. that are always running regardless of speed. Efficiency vs. Speed is a curve but TBF I've no idea where such a curve peaks.
 
OP
OP

bfrench

Member
First Name
Bill
Joined
Mar 9, 2021
Messages
21
Reaction score
47
Location
Utah
Vehicles
CyberTruck (tri-motor on order)
Occupation
Software
Country flag
What are you doing, using it as the base of a mutant vehicle?
No, just trying to build a predictive model that factors in possible increased (or reduced) range when using Cybertruck in use cases that involve very slow movements of the vehicle. Imagine a cable repair/maintenance use case where devices in the bed are drawing power and a very slow crawl across mostly flat spans. I'd like to create a dynamic model that predicts range given the very slow speeds.

Mostly paved surfaces, mostly flat - with a baseline I can probably adjust for inclines and gravel roads.
 
Last edited:
OP
OP

bfrench

Member
First Name
Bill
Joined
Mar 9, 2021
Messages
21
Reaction score
47
Location
Utah
Vehicles
CyberTruck (tri-motor on order)
Occupation
Software
Country flag
lots of variables we don't have.
Yep, understood. And thanks for raising the reduced wind resistance variable; I think that might be significant in terms of added range for CT, but less so for other models.

I wonder if it would be possible to determine how an existing Tesla vehicle would fare in this hypothetical since there's a lot more known about the performance. If anyone could reasonably calculate that a given Model 3 configuration at say 20mph would exceed the stated city range by perhaps +5% - that might help me on the modeling side. A really large ballpark precision is all I need for this modeling exercise. I'm just looking for a reasonable approach to back up the guestimate.
 

ajdelange

Well-known member
First Name
A. J.
Joined
Dec 8, 2019
Messages
2,953
Reaction score
3,145
Location
Virginia/Quebec
Vehicles
Tesla X LR+, Lexus SUV, Toyota SR5, Toyota Landcruiser
Occupation
EE (Retired)
Country flag
As you'd expect the range of my X goes down when it is driven at slow speeds. Drag is out of the picture at low speeds and the other loads evidently don't decrease as much as the motor efficiency does and the efficiency loss evidently rules. As I said above, this is a whole new motor going into the CT so things might be different with it.

In your use case you would be starting and stopping a lot and while regen means you are in a lot better shape than you would be without it there is still a small loss as it does not recover 100% of the energy. Thus the inertial load will creep up some.
 

Bluechip506

Active member
First Name
Steve
Joined
Dec 15, 2019
Messages
34
Reaction score
63
Location
Cypress, TX
Vehicles
Tesla Model S, Mazda CX9, Mazda Miata
Country flag
I imagine would be a long way. Someone went over 600 miles on one charge on a model 3 when out first came out. They averaged around 24mph if I remember correctly.
 

electricAK

Active member
Joined
Mar 5, 2020
Messages
31
Reaction score
76
Location
Haines, Alaska
Vehicles
Cybertruck dual-motor
Country flag
Below are charts of efficiency vs. speed for Model 3 and S. Obviously the CT will be less efficient overall, but I'd bet the curve will be the same shape.

6mph is really slow and really inefficient. I'd expect the range at 10km/h to be about 1/2 the EPA range. Note that this assumes constant speed, no stopping/accelerating which will further reduce efficiency.

https://forum.abetterrouteplanner.c...-consumption-real-driving-data-from-233-cars/

1624490994763.png

1624491303246.png
 

Wood Wombat

New member
First Name
Richard
Joined
Jun 29, 2020
Messages
3
Reaction score
5
Location
Melbourne, Australia
Vehicles
Tesla Model 3 Performance, Toyota Prado
Country flag
Below are charts of efficiency vs. speed for Model 3 and S. Obviously the CT will be less efficient overall, but I'd bet the curve will be the same shape.

6mph is really slow and really inefficient. I'd expect the range at 10km/h to be about 1/2 the EPA range. Note that this assumes constant speed, no stopping/accelerating which will further reduce efficiency.

https://forum.abetterrouteplanner.c...-consumption-real-driving-data-from-233-cars/


1624491303246.png
Funny, I was just using this graph today to estimate ideal speed when travelling long distances supported only by AC charging. Interestingly, for the scenarios that I was testing for my M3P, 500-1000km/day it is better to drive faster and charge longer (at 70km/h 11kW rate) than to mind your speed and drive longer.

I suspect that the CT will be very similar, although I am hoping for a 22kW onboard charger for that one. Australia has very large areas poorly served by DC fast chargers, but AC power is everywhere, even if it is with a diesel generator at times.
 

HaulingAss

Well-known member
First Name
Mike
Joined
Oct 3, 2020
Messages
671
Reaction score
1,136
Location
Washington State
Vehicles
2010 Ford F-150, 2018 Tesla Model 3 Performance
Country flag
Given a fully charged tri-motor Cybertruck, how many miles might it be able travel on level ground at 6mph?

I'm no energy or math wizard but I'll bet there's a pretty good estimate that could be made with some assumptions that obviously involve the motors. Anyone have an approach I should play with?
At very slow speeds you don't cover much ground per hour so you can drive all day and all night without charging (and then some). Even if the Tri-motors average EPA efficiency was cut in half at 6 mph, you could drive for over 41.6 hours non-stop! That's calculated by dividing 1/2 of the EPA range of 500+ miles (250+ miles) by 6 mph for over 41.6 hours or 1.7 days non-stop.

Of course, at such slow speeds, accessory loads become a large part of total consumption so you're not going to go for over 1.7 days with heater cranked to 70 degrees on a cold day and stereo blasting! Maybe only 24 hours or so.
 

JBee

Well-known member
First Name
JB
Joined
Nov 22, 2019
Messages
434
Reaction score
436
Location
6000
Vehicles
Cybertruck
Country flag
Interesting graphs which make sense seeing the non-drive parasitic loads with rolling resistance versus drivetrain loads only reach equilibrium at 40kmh, where aero is still insignificant.

But at lower speeds like 6mph (10kmh) there is are not many data points in those graphs so I'd be wary of making to many assumptions. What would be interesting to see in comparison is parasitic loads in a stationary vehicle in the same temperature conditions to plot against a speed/range graph. So actually harder to estimate than it looks like for such low speeds.

In a ideal world without parasitic loads the range would be infinite with a solar vault cover, (you can push a CT along by hand after all - like most cars) But it's unlikely the parasitic loads can be reduced that far. Does anyone know how much the self discharge is of a parked Tesla? And then one with "ignition on" but not in drive?

1624519372883.png
 
Advertisement

 
Advertisement
Top