Towing Range Expectations

[ajdelange]

Apparently control input from the front wheels put poles in the wrong place WRT sway. I'm not a controls guy but I suspect there are limits to how much you can defeat these with software. I'm more convinced that torque vectoring is the better solution by the fact that the ICE trucks that claim sway stabilization all seem to do it with torque vectoring rather than steering corrections. There certainly be others that I don't know about though.

Not really interested in pulling a heavy trailer but I used to pull a small one with a ProPride (Jim Hensley's design improved).

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[boxmonkeyracing]

This is a concern however it's no different than a gasser. Diesel is still more efficient at towing.

I had a 2013 1500 Silverado 5.3 towing a 12' enclosed trailer. When I moved from NC to KS. My average dropped 12 mpg from my normal 20 mpg to 8 mpg. Stopping every 200 miles sucked and made for super long days. In February I moved from Kansas to Florida. This time due to the increase in my family size and household goods I had a 2008 2500 HD Silverado Duramax towing a 28' trailer a total of 10k lbs. My mpg went from 19.5 normal highway to 12 mpg. This brings me to my point.

Expect a range decrease greater than 40%. Even Rivian confirmed via Twitter that a 7500 lb trailer/payload will depend on aerodynamics, but expectations are a range reduction of 45%.

For me, the truck works out great for towing my EV conversion project to the track nearby. If it's legit about a 240 in the bed I'll be able to top off my car between passes.

 

[ajdelange]

This is a concern however it's no different than a gasser. Diesel is still more efficient at towing.

Diesel is more efficient than gas (50% max for diesel to perhaps 35% for gas) but certainly not more efficient than electric (> 90%),

Expect a range decrease greater than 40%.

You can certainly expect range reductions of that much in some circumstances, more in others and less in still others. It depends on a lot of things. With ICE the main loads are inertial and gravitational so the loss depends mostly on weight. With an electric vehicle a lot of the inertial and gravitational are recoverable through regen so aerodynamic becomes more significant relative to those loads than it would be were regen not available.
Thus you are going to experience a bit less range reduction towing a particular trailer behind an electric vehicle than if you tow it behind an ICE vehicle over the same route in the same weather conditions at the same speed.

 

[boxmonkeyracing]

Diesel is more efficient than gas (50% max for diesel to perhaps 35% for gas) but certainly not more efficient than electric (> 90%),

You can certainly expect range reductions of that much in some circumstances, more in others and less in still others. It depends on a lot of things. With ICE the main loads are inertial and gravitational so the loss depends mostly on weight. With an electric vehicle a lot of the inertial and gravitational are recoverable through regen so aerodynamic becomes more significant.
Thus you are going to experience a bit less range reduction towing a particular trailer behind an electric vehicle than if you tow it behind an ICE vehicle over the same route in the same weather conditions at the same speed.

It all depends on where you're towing. If you're towing across the state/states you will not be recovering squat from regen. If you're towing in town the increase in power requirements to start moving are still greater. Even with the greater regen there will still be greater draw on the battery. This is no different than how electrics work without towing. That's why my Chevrolet Bolt can get over 370 miles running around town but only 190 on the freeway. Electrics are efficient in town, and you can thank regen for that. Without regen a petrol powered vehicle is better at distance.

 

[ajdelange]

It all depends on where you're towing.

Yes it does. Very much and when you are towing too. A bit of rain can cost you 1/4 of your range. A head wind can do you mischief but a tail wind will improve your range.

If you're towing across the state/states you will not be recovering squat from regen.

Your bio squib says you own an EV. Have you never looked at its energy displays? If you are towing on flat ground (and that means locally flat) and at constant speed regen won't do much for you. Under normal driving conditions it most certainly will. I think you are underestimating how much you change speed in nomal driving even on a freeway. Here's an exmple from a recent drive (across the state).

You are also ignoring the gravitational load which depends on the total distance you go up. For example if you are at sea level and go up a 100 foot hill, back down to sea level and then up a 200 foot hill and finally back to sealevel your gravitational load is m*g*(100 + 200). If coming down either of those hills it is necessary to use brakes for any reason that energy is lost forever. But in a BEV you can retain safe speed and recover a good portion (80% ?) of that energy thot would be lost to brakes..

If you're towing in town the increase in power requirements to start moving are still greater.

Atg slow speed of course the inertial load is greater than the drag load because the drag load is proportional to the square of the speed. But even so as regen reduces the effective inertial load, especially in town (see plot) the drag load becomes more significant than it would be without regen, Perhaps you misinterpreted what I wrote to mean that the drag load would become greater than the inertial load and I'd have to take some of the responsibility for that given that I wasn't really clear. What I meant was that the relative proportions of the total load would change to make the drag load a larger chunk of the whole. I edited the post e.g. Drag:Inertial:Other:: 20:60:20 ---> 40:40:20..

Even with the greater regen there will still be greater draw on the battery.

Greater than what?

This is no different than how electrics work without towing.

That's true with the difference being the mass. The inertial load is m*v*a in which m is the mass, v the velocity and a the acceleration. IOW it is proportional to he mass, the speed and the acceleration. So your peak power and peak battery current will be higher if you leave each stoplight like Sterling Foss but the amount of energy you use to get to v is m*v*v/2 regardless of your acceleration profile. The more regen you have the more of this you recover and the more miles you get per watt hour. As drag is very low at low speed it's really not a factor. What determines how you do is grade and mass.

That's why my Chevrolet Bolt can get over 370 miles running around town but only 190 on the freeway.

It can't be that bad! If it is it's because the car has the drag coefficient and frontal area of the Titanic. Inertial load is linear with mass and velocity, Drag load goes as the cube of velocity (but does not depend on mass). Thus at higher speed eventually you come to the point where drag overcomes inertial and other losses and becomes dominant. That's shown in the following consumption data extracted from a years worth of drives in my X100D

You can clearly see the loss of efficiency at lower speeds and. above 35 mph, the drag starting to creep in. The fit shows the coefficient for the squared velocity term which is proportional to drag to be about 0.05. Putting in your numbers and making an assumption that your Wh/mi are about 200 at 35 mpH says that your drag is 3 times that of the X and that just doesn't make sense. So something wrong with your observations and hence your conclusion.

Electrics are efficient in town, and you can thank regen for that.

Yes they are but they are also efficient on the highway, My data shows it. Overall I got 301 Wh/mi with that X city, country, freeway, dirt road...

Without regen a petrol powered vehicle is better at distance.

When one says something is better he must tell us what his criterion for goodness is so you'll have to be more specific here. But clearly in terms of energy used per mile traveled ICE and diesel vehicles are far inferior to BEVs. Even with gas being as cheap as it is at he moment they aren't better in terms of cost. They aren't better in terms of maintenance, or emissions or anything else I can think of except the time it take to top them off.

 

[boxmonkeyracing]

Yes it does. Very much and when you are towing too. A bit of rain can cost you 1/4 of your range. A head wind can do you mischief but a tail wind will improve your range.

Your bio squib says you own an EV. Have you never looked at its energy displays? If you are towing on flat ground (and that means locally flat) and at constant speed regen won't do much for you. Under normal driving conditions it most certainly will. I think you are underestimating how much you change speed in nomal driving even on a freeway. Here's an exmple from a recent drive (across the state).

You are also ignoring the gravitational load which depends on the total distance you go up. For example if you are at sea level and go up a 100 foot hill, back down to sea level and then up a 200 foot hill and finally back to sealevel your gravitational load is m*g*(100 + 200). If coming down either of those hills it is necessary to use brakes for any reason that energy is lost forever. But in a BEV you can retain safe speed and recover a good portion (80% ?) of that energy thot would be lost to brakes..

Atg slow speed of course the inertial load is greater than the drag load because the drag load is proportional to the square of the speed. But even so as regen reduces the effective inertial load, especially in town (see plot) the drag load becomes more significant than it would be without regen, Perhaps you misinterpreted what I wrote to mean that the drag load would become greater than the inertial load and I'd have to take some of the responsibility for that given that I wasn't really clear. What I meant was that the relative proportions of the total load would change to make the drag load a larger chunk of the whole. I edited the post e.g. Drag:Inertial:Other:: 20:60:20 ---> 40:40:20..


Greater than what?


That's true with the difference being the mass. The inertial load is m*v*a in which m is the mass, v the velocity and a the acceleration. IOW it is proportional to he mass, the speed and the acceleration. So your peak power and peak battery current will be higher if you leave each stoplight like Sterling Foss but the amount of energy you use to get to v is m*v*v/2 regardless of your acceleration profile. The more regen you have the more of this you recover and the more miles you get per watt hour. As drag is very low at low speed it's really not a factor. What determines how you do is grade and mass.

It can't be that bad! If it is it's because the car has the drag coefficient and frontal area of the Titanic. Inertial load is linear with mass and velocity, Drag load goes as the cube of velocity (but does not depend on mass). Thus at higher speed eventually you come to the point where drag overcomes inertial and other losses and becomes dominant. That's shown in the following consumption data extracted from a years worth of drives in my X100D

You can clearly see the loss of efficiency at lower speeds and. above 35 mph, the drag starting to creep in. The fit shows the coefficient for the squared velocity term which is proportional to drag to be about 0.05. Putting in your numbers and making an assumption that your Wh/mi are about 200 at 35 mpH says that your drag is 3 times that of the X and that just doesn't make sense. So something wrong with your observations and hence your conclusion.

Yes they are but they are also efficient on the highway, My data shows it. Overall I got 301 Wh/mi with that X city, country, freeway, dirt road...


When one says something is better he must tell us what his criterion for goodness is so you'll have to be more specific here. But clearly in terms of energy used per mile traveled ICE and diesel vehicles are far inferior to BEVs. Even with gas being as cheap as it is at he moment they aren't better in terms of cost. They aren't better in terms of maintenance, or emissions or anything else I can think of except the time it take to top them off.

Ok, let me break some info down for you. I have been in aircraft maintenance for the last 18 years. Aerodynamic drag I understand. I also understand weight because I need to for my job.

Now, I do know how much I change speed on the freeway. I know from experience what my Bolt EV is capable of and when there's a head wind or tail wind that is influencing it. So, let's take the average of 190 miles on the interstate for Kansas, Oklahoma and Missouri. That is over 100 trips. The EPA rating is 238 miles. 190/238=.798 or 79.8%. So 20.2% range compared to the EPA estimate. Now let's add RJ Scaringers estimate of 30+% (see attached)... See my point? Now both the Rivian and Cybertruck aren't out and all we have is the what Tesla thinks the EPA estimate will be. We can do rough estimates for the Cybertrucks interstate range, but again it's an estimate. IMO you'll see 200-260 miles in the tri motor traveling on the interstate.

Lol. At the better section. Do I really have to spell that out. Space, distance due to how much fuel you can carry, how fast to turn around in a fuel stop... I love EVs, but ice is still better for long distance traveling. Unless you have 4 dogs and need to stop every 2-3 hrs to let them get exercise.

Now I'm going to go work on my EV conversion project and ig

 

[ajdelange]

Now, I do know how much I change speed on the freeway. I know from experience what my Bolt EV is capable of and when there's a head wind or tail wind that is influencing it. So, let's take the average of 190 miles on the interstate for Kansas, Oklahoma and Missouri. That is over 100 trips. The EPA rating is 238 miles. 190/238=.798 or 79.8%. So 20.2% range compared to the EPA estimate. Now let's add RJ Scaringers estimate of 30+% (see attached)... See my point? Now both the Rivian and Cybertruck aren't out and all we have is the what Tesla thinks the EPA estimate will be. We can do rough estimates for the Cybertrucks interstate range, but again it's an estimate. IMO you'll see 200-260 miles in the tri motor traveling on the interstate.

You are making the common mistake of assuming that because you obtain 80% efficiency on the freeway that everyone does. I obtain 98 - 100% on hilly freeway and 104% overall (in my old X). But I don't presume to tell anyone that he will get 104% of 500 miles in his new EPA 500 miles rated CT based on my experience. In advising people what to expect I turn to the fleet statistics. The picture below shows the attained efficiency of the portion of the Tesla Fleet that subscribes to Stats:

As you can see the mode is about 85% and the average is probably close to that as around 84% is the average for winter time but we are climbing out of that and headed for the 96% average Tesla drivers experience in the warmer months. Note that the 107% figure is for my new X which only has 380 miles on it at this point.

Thus if I were to predict range for the CT I'd say it's going to be about 450 miles in summer and 420 miles in winter for the average driver but point out that half will do worse than that and half better ane that each will experience appreciably above and below his average. 200 - 250 miles would represent, in a 500 EPA mile vehicle, efficiencies of less than 50% and is clear from the histogram that only 1 or 2 percent of drivers will do that poorly.

Now when you add a trailer, of course, the picture changes. In the low speed regime it is the inertial and gravitational loads that dominate even with regen and so adding a trailer that weighs as much as the truck will cut the range about in half. Try to pull that same trailer at 70 or 80 mph and drag becomes a major player with range reduced to well below 50%.

Now I'm going to go work on my EV conversion project and ig

Hope the iging goes well.

 

[TyPope]

That totally proves my concern. I towed my RV with F150 and it is not efficient at all. You loose third of the mileage per gallon so about 6-8 mpg. Based on the initial video I posted and this video, it is the same for EV. Problem is recharging. While one refills F150 at the stop for 15 minutes, Tesla would have to get a full charge which takes considerably longer and not very practical. You have to keep in mind that there are a few hypotheticals on numbers here and situation will not be quite as bad. Hoping Elon keeps that in mind, otherwise I switched to a tri motor from my initial dual configuration. Missing FSD now :/
As a business man, Elon probably not targeting truck owners who actually uses them as tow vehicles. Based on stats, not that many truck owners do tow. I don’t think he will make sure that he targets that smaller group and instead go after people who does not need tow range, just ability to drive their butt with some junk in their trunk.

I'd add FSD if I were you. In 2-3 years, you may decide you want it and by then, the price could have gone way up. You can always remove it from your order later but adding it now kind of locks in the lowest price.

 

[boxmonkeyracing]

You are making the common mistake of assuming that because you obtain 80% efficiency on the freeway that everyone does. I obtain 98 - 100% on hilly freeway and 104% overall (in my old X). But I don't presume to tell anyone that he will get 104% of 500 miles in his new EPA 500 miles rated CT based on my experience. In advising people what to expect I turn to the fleet statistics. The picture below shows the attained efficiency of the portion of the Tesla Fleet that subscribes to Stats:

As you can see the mode is about 85% and the average is probably close to that as around 84% is the average for winter time but we are climbing out of that and headed for the 96% average Tesla drivers experience in the warmer months. Note that the 107% figure is for my new X which only has 380 miles on it at this point.

Thus if I were to predict range for the CT I'd say it's going to be about 450 miles in summer and 420 miles in winter for the average driver but point out that half will do worse than that and half better ane that each will experience appreciably above and below his average. 200 - 250 miles would represent, in a 500 EPA mile vehicle, efficiencies of less than 50% and is clear from the histogram that only 1 or 2 percent of drivers will do that poorly.

Now when you add a trailer, of course, the picture changes. In the low speed regime it is the inertial and gravitational loads that dominate even with regen and so adding a trailer that weighs as much as the truck will cut the range about in half. Try to pull that same trailer at 70 or 80 mph and drag becomes a major player with range reduced to well below 50%.


Hope the iging goes well.

So, stats are great and all, but if the bulk of your random data point sources are in southern California you have a skewed number.

Now I don't know the source locations on that application. I'm not going to pretend to know either. I'm also not going to do the leg work to prove my point. I don't care enough. I will say being that the bulk of Tesla registrations have been in California. That means the bulk of your data points has a very high probability of being from California.

But I'm done. No need to respond directly to me as the proof will be in the pudding when the truck is out, and legitimate stats are available.

 

[TyPope]

I said above I didn't think you could haul a large trailer from Quebec to Florida. I subsequently put some numbers into ABRP. I assumed 400 WH/mi for the Cybertruck and another 400 Wh/mi for the trailer. With a 100 kWh battery one would have to stop 22 times to charge (every 100 miles or less) taking a total of 13 hrs (30 hrs driving time) at the stalls. The good news with the CT relative to, e.g., the R1T, is that there are plenty of SC's charging reasonable rates ($257 total for the trip). With the 175 - 200 kWh battery that the trimotor CT will have presumably one could go twice as far between charges reducing their number to 11 but it would still require 13 hours of charging and the costs would still be about the same. I guess that is something that one might consider doing were it only twice per year.

Another problem that has not been mentioned is that most Tesla SC stalls are designed to have a car back up to them. Some stations will have one or two "pull through" stall which accommodate trailers. Thus the spectre of having to unhitch at each charge raises its ugly head.

Also ran the numbers for the R1T again doubling the power drain for the trailer. Fifteen charges would be required but the estimated cost zooms to $726.

Unhooking, while a pain in my current truck, will be much easier in the CT. Pull into a spot, raise the rear, swing down the trailer front jack, lower the CT away from the trailer, unhook elect/chains and drive away. Hooking up SHOULD be very automatic, Tesla being Tesla... same with scooping that ball under the hitch and just picking the trailer off it's jack leg. At least you won't have to wind up and down the jack leg any more.

 

[ldjessee]

I think what will make a bigger difference to long range towing is a trailer that fits the truck better. Something that would also help ICE truck owners.

Putting the air back is just as important, or more so, than pushing it out of the way, for efficiency at speed. Thus, making a trailer that is no wider than the Cybertruck, and try to keep it the same height as possible would be a huge help. A fitted 5th wheel, as pointed out in this render in this video, would help with aerodynamics of towing. And that kind of shape could be adapted to an enclosed utility trailer.

 

[Geo]

You are making the common mistake of assuming that because you obtain 80% efficiency on the freeway that everyone does. . . .


Thank you to both of you, Ajdelange and BoxMonkeyRacing, both made some good points, and you both made me realise I have missed a big point, which I'll get to at the end.

Its not a mistake to think about what efficiency you yourself will typically get vs what others do.

I.e. If you consistently achieve EPA range but others who may drive very gently /conservatively and hypermile may attain a greater figure. And others less so.

But in your to and fro you made me realise 3 things.

A/ The EPA range for EV's doesn't commonly get broken out into City and Highway range, So need to be mindful the 300 and 500 mile range of CT is an aggregate of the two and so it will certainly be less for Highway, whatever the figures finally get firmed up at.

B/ 82% efficiency is about the common usual experience for most, I certainly wont be nursing it around to get a better figure, I will be using the HVAC and stereo etcetera, and driving around in bad weather half the time. Which Ajdelange confirms means a drop of 25% in range just for that.

C/ Oh shit, my highway driving while towing has now become a problem, I have reserved the dual motor with 300 mile range.
So the highway range for that maybe around 265 miles.
So I need to base my plans around losing 55-60 % of the 265 mile range, which is now a lowly, 106 miles !
I hope the "plus" in "300 plus miles" is significantly more.

 

[ajdelange]

Its not a mistake to think about what efficiency you yourself will typically get vs what others do.
I.e. If you consistently achieve EPA range but others who may drive very gently /conservatively and hypermile may attain a greater figure. And others less so.

That's the most important part of the message. These numbers are statistics. Statistics are useful for certain things such as telling a health department how many mortuary bags to buy for the current phase of corona but they won't tell you whether you are going to wind up in one or not.

Those of you who do not currently drive Teslas are in for a lot of pleasant surprises. One is that the cars come with multiple odometers that tell you how many watt hours per mile you have consumed since you put the car in D, how many since you last charged it and how many since you reset each of two additional which can be used a trip odometers. Many never reset one of those and thus know Wh/mi for the life of the car. I use the other for trips and for seasons so I know, for example, that winter use with the heater doesn't have to be as bad as is often reported. Using the first two a motivated driver quickly learns what driving conditions do to his energy consumption and use that in planning. In addition to the OD's graphical information is displayed concerning consumption during a trip so that one quickly detects, for example, the effect of a headwind or wet road bed. He also learns how to get better efficiency IOW how to hypermile if that's what he wants to do or needs to do in a particular situation. The trick is to understand what all this data you are being showered with tells you. Unfortunately modern western education policy suppresses STEM and so the schools turn out people who don't know what an average means or implies and do this in the middle of an information revolution. No more on that.

A/ The EPA range for EV's doesn't commonly get broken out into City and Highway range, So need to be mindful the 300 and 500 mile range of CT is an aggregate of the two and so it will certainly be less for Highway, whatever the figures finally get firmed up at.

It is supposed to be representative of what a user can expect but it is just another statistic. I think you can be pretty certain of the 300 and 500 mile figures. The actual numbers will probably be 504 an 302 or something like that. Tesla will not fall flat on its face by coming in under those numbers.

As to what you will get: you will get what you get and that will depend on where and how you drive. As I recall the limit in Victoria is 100. If you stick to that I don't think you will find much difference between city and highway. Going up the Stuart at 130 would be a different matter.

C/ Oh shit, my highway driving while towing has now become a problem, I have reserved the dual motor with 300 mile range.
So the highway range for that maybe around 265 miles.
So I need to base my plans around losing 55-60 % of the 265 mile range, which is now a lowly, 106 miles !
I hope the "plus" in "300 plus miles" is significantly more.

If you look at the design of the TriMotor it is pretty clear that the towing application drove it. Separate induction motors in the rear give the torque needed to get a huge load moving and the battery is sized to allow one to tow it a fair distance not to mention the torque vectoring capability for suppressing trailer sway. Most people, of course, won't tow with it but they still get the huge benefit of 500 mile range which derives from the large battery required for towing. Were towing a requirement or the main reason for getting the truck I would really think about the TriMotor if at all possible.

 

[israndy]

This worries me:

 

[ajdelange]

There is plenty of material in this thread explaining why you shouldn't be but if you have no experience with driving BEVs I think it is perfectly reasonable that you are.

Grossly simplifying things, towing eats about half your range. In a 295 EPA mile X, therfore, expect about 150. In a 500 mile trimotor CT expect about 250. If you are worried by that (there will be times when the range will be even less) then perhaps you should not be considering a BEV truck.

If you want to go from Boulder to Portland towing your 12,000 pound fifth wheel camper at a leisurely pace in chunks of a few hundred miles a day then a CT is fine. If you are in business to transfer loads of this size from Boulder to Potland on a recurring basis then it isn't.