Blade Runner Redux - Tesla Cybertruck!

[oldtamiyaphile]

https://www.youtube.com/watch?v=L2nSIDv29HE

Finally some analysis from someone who understands structual engineering.

[aerohead]

Originally Posted by Hersbird

The nice thing about a diesel puller is you don't lose as much range when working, maybe 1/3. Also a gas puller gets into a better thermal efficiency area when it's working so while it may lose 1/2 it's range that's not as bad as the EV which gains no efficiency with added work and loses 2/3 of it's range.

I've been going back through my archive,compiling trailer towing road tests from over the decades.I'm no sooner than a week away from sharing anything meaningful if I work full-time on it.
Shooting from the hip though,I wouldn't want to make a blanket statements about BEV towing capabilities.
I've seen an ICE Sedan-Airstream/ ICE Sedan-'Box' Trailer comparison,where the sedan got as little as 25% of it's solo mpg while towing.
I've identified over half a dozen criteria which would have to be quantified for any tow test to be meaningful.And typically,it's what's not mentioned,that's more important than what is.

[aerohead]

Originally Posted by Hersbird

On the highway, cargo completely enclosed inside isn't going to affect gas, diesel, or EV significantly .
There are downhill roads that even with max regen braking are going to require either nauseatingly slow speeds or actual friction brake applications. We have a lot of passes here that have nice long straight downhills, followed by 25 mph hairpins, followed by nice long straight sections. You could probably just hold 30 mph on the whole thing but you usually let it pick back up some speed. TFLcar has been doing some EV testing up and down Loveland pass in Colorado from 5000 ft Boulder to 12,000 foot summit and they still don't gain much if any battery back onnthe downhill. They also run climate control and maintain speed limits and such to try and make it what a normal person might expect. They have only done the Kona and the Golf but they have a Model X too, I just haven't seen that episode. The Golf actually couldn't make it without a mid charge, but the Kona did it no sweat with 120 miles of range left.

I've watched the TFLcar Tesla Model X-Cimmaron tow test on Loveland Pass.Here are some observations:
*The RAM pickup pulled the horse trailer at 70-mph,10-mph over the posted speed limit.
*The S.A.E. Davis Dam tow-tests are conducted at 35mph-55-mph.
*The RAM was not pulling it's maximum rated weight,as was the Tesla.
*The ratio of trailer frontal area-to-RAM frontal area was a fraction of that for the Tesla.
*With a 1,068.8 kWh pack,the RAM had a climbing range of 278.8-miles,consuming 3,389 Watt-hours/mile.
*@ 8.7-mpg,the RAM was getting 51.1% of its solo mpg.
*The RAM descended Loveland Pass at 70-mph.
-------------------------------------------------------------------------
*No aerodynamic accounting is made for the addition of tow mirrors to the Tesla.
*The Tesla was pulling it's gross trailer weight,unlike the RAM.
*The Tesla was not allowed to 'enter' the climb,already 'cruising' at 70-mph.
*The Tesla was not allowed to maintain its 70-mph speed up the incline.We are not given a complete accounting for a 70-mph climb/pull.
*The ratio of trailer frontal area,to that of the Tesla is out of proportion compared to that of the RAM.
*Again,the test velocity exceeds that of S.A.E. Davis Dam protocol.
*The Tesla was not allowed to descend the grade at 70-mph,ruining its ability to harvest the down-slope with regen (which only recovered 12-miles of range and 4% battery,from 60-mph,instead of 19-miles).
*The Tesla never 'braked' on the down-slope.No kinetic energy was lost to friction-heating at the rotors/pads.
*If the Tesla had a pack as large as the RAM,its solo range would be 4,238.9-miles.Pulling any kind,and any weight of trailer up to Eisenhower Tunnel would be a wash.
It would be a great service to all consumers (since we're no longer citizens)to have all testing done,following a standardized checklist,including all pertinent data.Garbage in,garbage out.

[Hersbird]

I wasn't even talking about the Loveland pass video (when discussing EV towing at least, the reference above was just normal EV testing that shows you don't gain as much as you might think you will on the downhill), they had another where they try and tow a trailer to Oregon for a show and just get killed on the range and the real problem, the recharge times vs gas. They called in the Ram to finish the trip, it was still faster many hours into the run to start the whole trip over from the beginning with the Ram. The trailer used in that video was much lighter and had a smaller frontal aera but still just destroyed the range on the Model X.
https://youtu.be/yjklex38lkQ

[aerohead]

Originally Posted by Hersbird

I wasn't even talking about the Loveland pass video, they had another where they try and tow a trailer to Oregon for a show and just get killed on the range and the real problem, the recharge times vs gas. They called in the Ram to finish the trip, it was still faster many hours into the run to start the whole trip over from the beginning with the Ram. The trailer used in that video was much lighter and had a smaller frontal aera but still just destroyed the range on the Model X.
https://youtu.be/yjklex38lkQ

I watched that one as well.Why they chose the biggest aerodynamic abortion to ever cast a pall across the United States I don't know.The BOREAS SERIES XT has got to be the poster child for full-excrescence trailers.
Flat-plate envelope to destroy the flow to the spare tire,which further destroys the flow to the nose mounted pet mausoleum,which conspires to separate the flow before it can reach the torture-chamber hard edges,top-and sides,then they throw 18-inches of rectilinear gravestone onto the roof rack,glom on a 3'-by-3'-by-1' tumor onto the passenger side,then an 8-gallon propane tank to guarantee full separation on that side of the trailer,on top of fenders which protrude a full 1-foot on both sides,to deliver the coup de grace.Add the exposed wheels and axle barnacles to finish off the effect.
I didn't know it was legal to sell parachutes for the highway.
And of course,you must drive it at 75-mph.No concessions.
Since the Tesla is a full-attached flow body,it has no benefit of a large wake in which the trailer may be embedded,like the HUMMER H-2 which towed the Cimmaron horse trailer to Denver,for the other test.
If you wanted to 'rig' an aerodynamic test,well then,I give them an A-Plus!
I would be strained to the limit to find anything charitable to say about the testers.A technical conspiracy hiding in plain view.

[redpoint5]

I wonder, in that Tesla/trailer stunt, did they calculate the most time efficient speed to travel?

In ICE vehicles, there is no practical limit to speed vs efficiency with regard to time. Going 100 MPH will get you to the destination faster even if you have to stop more often to refuel, but that's because refueling is so quick and available. Not necessarily so with an EV. I once calculated the theoretical optimal speed to travel in a Chevy Bolt to be about 77 MPH for completing a long distance trip in the shortest amount of time. That car is limited to ~50 kW charging, and severely tapers charging rate shortly after 50% state of charge.

That brings me to the next question; did they determine the optimal amount of time to spend recharging and plan their stops accordingly? It's very inefficient time-wise to charge above a certain state of charge due to tapering. You end up being better off stopping more frequently but for shorter durations.

So, I wonder what the efficiency of the Tesla and trailer was at various speeds, and if there was any lower speed that would have been more time efficient to travel at? I suspect not since Teslas have a higher charging rate, but still curious to see the analysis.

[aerohead]

Originally Posted by redpoint5

I wonder, in that Tesla/trailer stunt, did they calculate the most time efficient speed to travel?

In ICE vehicles, there is no practical limit to speed vs efficiency with regard to time. Going 100 MPH will get you to the destination faster even if you have to stop more often to refuel, but that's because refueling is so quick and available. Not necessarily so with an EV. I once calculated the theoretical optimal speed to travel in a Chevy Bolt to be about 77 MPH for completing a long distance trip in the shortest amount of time. That car is limited to ~50 kW charging, and severely tapers charging rate shortly after 50% state of charge.

That brings me to the next question; did they determine the optimal amount of time to spend recharging and plan their stops accordingly? It's very inefficient time-wise to charge above a certain state of charge due to tapering. You end up being better off stopping more frequently but for shorter durations.

So, I wonder what the efficiency of the Tesla and trailer was at various speeds, and if there was any lower speed that would have been more time efficient to travel at? I suspect not since Teslas have a higher charging rate, but still curious to see the analysis.

Once the trailer hitch is installed,the Tesla 'knows' that its in Trailer Mode.Once underway,the car self-interrogates itself,modifying its appraisal of range with respect to real-time demand.
At a SuperCharger station,the car will recommend when to cease charging and resume travel,not necessarily having you leave with any close to a full charge.
There's a whole Tesla owners website where they post trip data,trailers they pull,and strategies for travel.I get the sense that the trip is the experience,not necessarily the destination.From these posts you can see Model X owners getting 373 Wh/mi pulling shrunken Airstreams at 55-mph,with climbs of 2500-feet,compared to around 253 Wh/mi solo;no worse than some ICE vehicles.They also report the amount of regen power recovered as a function of road grade.

[freebeard]

...pulling shrunken Airstreams...

UWU. I await the pix.

[Hersbird]

Originally Posted by redpoint5

I wonder, in that Tesla/trailer stunt, did they calculate the most time efficient speed to travel?

In ICE vehicles, there is no practical limit to speed vs efficiency with regard to time. Going 100 MPH will get you to the destination faster even if you have to stop more often to refuel, but that's because refueling is so quick and available. Not necessarily so with an EV. I once calculated the theoretical optimal speed to travel in a Chevy Bolt to be about 77 MPH for completing a long distance trip in the shortest amount of time. That car is limited to ~50 kW charging, and severely tapers charging rate shortly after 50% state of charge.

That brings me to the next question; did they determine the optimal amount of time to spend recharging and plan their stops accordingly? It's very inefficient time-wise to charge above a certain state of charge due to tapering. You end up being better off stopping more frequently but for shorter durations.

So, I wonder what the efficiency of the Tesla and trailer was at various speeds, and if there was any lower speed that would have been more time efficient to travel at? I suspect not since Teslas have a higher charging rate, but still curious to see the analysis.

They actually did. If you watch the video early into the trip the father is saying he would rather skip the first charge as there is plenty of range to make the 2nd but the son is relying on the software to limit charging times by keeping it in a better battery charge state.

Not replying to you now but Aerohead. As far as speed they didn't keep it at 75. They did initially but saw they wouldn't even make some of the relays so they slowed down to 65. The semis were passing them. Would 55 or even 45 mph probably saved them time overall? Probably. But at 45 you would probably literally get a ticket on those interstates. They probably could have found back roads but then the distances would have been longer and the superchargers possibly non existent.

The trailer may have been poor aero, but it's better than normal, and probably 1/2 the frontal aera of normal as far as campers go.

They were just doing what a normal user would do, I'm sure they were back to 75 mph travel with that tiny camper once it was back behind the Ram.

This is why I question the reality of what it will be like to tow with the Cybertruck. Even with better range, I see that only happening with bigger battery. So any gain at one end is lost on the charging end when it comes to more than a couple hundred miles.

[aerohead]

Originally Posted by freebeard

UWU. I await the pix.

Check out Happier Campers HC1.It looks like kin to Casita, Scamp,and Bambi.