# Tesla's new truck and hipper sports car



## aeroscott (Jan 5, 2008)

We had a thread on this forum on over the road trucks .My point was that 
Trucks get 6 to 10 mpg and gross 80,000 lbs, meaning that they get great mpg / ton. IE;a MB 320 CDI will get 32 to 40 mpg @ 5,000 lbs gross , that's 5 times less energy then the Mercedes per ton . That means battery weight will have 5 times less negative effect or like a Tesla S with a 240 lb. battery.
Elon says 20% less operating cost. 
It's always been about the battery,who can make those Elon!
Oh the sports car $200,000 ,1.9 sec. 0 to 60 mph ,600 mile range with 200kwh battery.
What are the talking heads Tesla shorts going to say this morning . HE has never made a deadline, neither have 99% of people doing new hard things.


----------



## Kevin Sharpe (Jul 4, 2011)

Here's the best short video that I found


----------



## PhantomPholly (Aug 20, 2008)

Funniest Musk quote ever:



> "Driving a gasoline sports car is going to feel like a steam engine with a side of quiche"


----------



## brian_ (Feb 7, 2017)

There certainly is a pattern in these trucks (including the Nikola Motor proposal): the cab extends forward and narrows, which is good for aerodynamics and is made easier by the lack of need for engine access or clearance for the top of an engine. Unfortunately, it makes access to the door more difficult, leading to this bizarre enter-by-the-back-door system.

I have no idea why this truck wasn't shown months - or years - ago, since there is nothing very new in it. I suppose Tesla Motors just needs some good press to offset the continuing Model 3 production disaster. 

How easy is it to build a prototype like this? Single-speed motor-driven axles are commercially available for large road vehicles. Multiple manufacturers offer multi-speed gearboxes specifically for electric motors (although usually in smaller sizes). Cummins currently makes only engines, and put together a battery-electric truck to promote their proposed electric powertrain products.... using a race car fabricator (which has never built a truck before) to do the work.

I think Wrightspeed has the right idea. Whether you agree with Wrightspeed's hybrid approach or prefer straight battery-electric, long-haul trucks are not a rational place to put expense and effort, if the purpose is to reduce fossil fuel consumption. Stop-and-go operation of transit (buses - already available), service (think garbage), and local delivery vehicles is a more useful but less attractive market; Cummins targeted Class 7 urban hauling with their tractor, and Mercedes Fuso chose a medium-duty straight truck.


----------



## brian_ (Feb 7, 2017)

*"Semi"*

I think it's hilarious that Musk has chosen "Semi" as the name for his truck. 
Semi | Tesla

The term "semi" means "half", referring to trailers which are not full trailers (entirely supporting themselves, with wheels at both ends, like an old horse-drawn wagon) or pony trailers (balanced on one set of wheels, with only a small part of the weight carried by the tow vehicle, like recreational trailers and small trailers drawn by a single horse), but half-supported by their own wheels at the back and half-supported by the tow vehicle at the front. So it's the _trailer_ which is a semi-trailer; the _truck_ pulling a semi-trailer is a *tractor*. But sure, this might be a semi-useful truck. 

I suppose that "Tractor" wasn't an appealing name.


----------



## brian_ (Feb 7, 2017)

*Energy consumption rate*



aeroscott said:


> ...
> Trucks get 6 to 10 mpg and gross 80,000 lbs...


Diesel contains about 10 kWh/L, or 38 kWh/USgal. 6 to 10 mpg or 0.17 to 0.10 USgal/mile is then 6.3 to 3.8 kWh/mile (of chemical energy, not electricity)... and personally I think the 6 mpg end of the range seems more likely if actually loaded anywhere near 40 tons.

With a battery-electric truck using energy output from generating stations (not the raw fuel input to them), and engine efficiency of roughly one-third, the 2 kWh/mile energy requirement claimed by Tesla seems roughly reasonable. On the other hand, Nikola Motors loudly claimed in Twitter that's low... they say "2.5 to 3.1 kWh/mi to move freight at 65-70 mph at load(Flat ground)." Of course all electric heavy truck proposals include substantial aerodynamic improvements over typical trucks - they all have sleek noses and the Tesla display model has an impossibly well-faired cab to trailer gap.

Of course, neither Tesla Motors nor Nikola Motors has an actual functioning truck, which is why they can't show them. Yes, they can drive onto a stage, but the acceleration "video" is a simplistic computer graphic, not an actual truck towing an actual loaded trailer to highway speed.


----------



## Kevin Sharpe (Jul 4, 2011)

Tesla Semi Charge Port


----------



## PhantomPholly (Aug 20, 2008)

brian_ said:


> I think Wrightspeed has the right idea. Whether you agree with Wrightspeed's hybrid approach or prefer straight battery-electric, long-haul trucks are not a rational place to put expense and effort, if the purpose is to reduce fossil fuel consumption. Stop-and-go operation of transit (buses - already available), service (think garbage), and local delivery vehicles is a more useful but less attractive market; Cummins targeted Class 7 urban hauling with their tractor, and Mercedes Fuso chose a medium-duty straight truck.


A hybrid certainly makes more sense today. Once they improve the energy density sufficiently, or come up with a viable and standardize battery replacement system for long-haul truckers, then it will no longer make sense to have the duplicate power systems. Wrightspeed is certainly interesting, but again I would question the use of the micro-turbine - after all, I don't believe they are claiming it is actually more efficient than some piston alternatives. Something else capable of generating exactly the maximum steady-state driving power, perhaps a free piston diesel, might be more efficient.


----------



## Kevin Sharpe (Jul 4, 2011)

Tesla Roadster 2


----------



## aeroscott (Jan 5, 2008)

just talked to my trucker buddy says 8mpg loaded and 120,000 miles per year 15,000 gallons per year @$3.00/gallon $45,000/ year.
1000 kWh battery X $100 /kWh =$100,000
1000kWh @$ .07/ kWh = $70.00
500 miles /8mpg= 62.5 gallons diesel X3.00/ gallon=$187.00


----------



## Kevin Sharpe (Jul 4, 2011)

Some impressive numbers from Tesla...


----------



## aeroscott (Jan 5, 2008)

Thanks for posting Kevin,twice the range I didn't see that coming.
It probably cost $200,000 a year for Bugatti maintenance


----------



## aeroscott (Jan 5, 2008)

The talking heads on CNN are laughing at Elon's flying car this morning , not
even mentioning the semi or hipper car. They can't be that teck illiterate.


----------



## brian_ (Feb 7, 2017)

These comparisons with a Bugatti Chiron are hilarious. They must start with writers who know nothing about cars, or with marketing people.

The Chiron's price has nothing to do with value or cost of construction: they exist for owners to use to flaunt their wealth. If the same car sold for twice the price, more people would want it.  It certainly makes it a good target for idiotic comparisons.

One comparison is the aerodynamic drag coefficient of the Telsa Semi and the Chiron. That's insane: much of that car's drag is induced due to downforce - the Chiron is not intended to be a low-drag design. Nearly every car in current production has a lower CD than a Bugatti or the Tesla Semi; they picked the Chiron because they assumed that their audience would be too ignorant to realize that it was ridiculous. An honest comparison would be with real production tractor-trailer rigs... and besides being useful it would look even better because real trucks drag coefficients run much higher than claimed for the Tesla Semi (with its unworkable trailer fairing).

In the table with the comparison with the Chiron, they should add "time to refuel" and "number of available refuelling stations". If they're going to compare performance, where are the values for lateral acceleration or lap time around a test track?

Maybe for their next model, Tesla can compare performance with a Toyota Prius, fuel economy with a Rolls-Royce, and interior room with a Ferrari.


----------



## brian_ (Feb 7, 2017)

aeroscott said:


> The talking heads on CNN are laughing at Elon's flying car this morning , not even mentioning the semi or hipper car. They can't be that teck illiterate.


"teck" illiterate? 

They are probably tech literate enough to know that the truck and targa coupe are not particularly interesting, that flying cars in general are a long-running joke, and that Musk's tweet about an upgrade package for the Roadster using rockets to make the car hop is a joke... so they were laughing at it.


----------



## aeroscott (Jan 5, 2008)

Brian, are you saying the tesla semi and the sports car are not game changing events .If so what is interesting .
The Bugatti is not a super car and has no state of the art engineering.
It sounds like you just don't like ev's or engineering , you didn't talk about 20% less cost and the ability to do 500 miles , that's all that matters to trucking company's, except you did mention refueling but so did elon and has done it before(supercharger)


----------



## brian_ (Feb 7, 2017)

aeroscott said:


> Brian, are you saying the tesla semi and the sports car are not game changing events .If so what is interesting .


The Semi is no more "game changing" than the other electric heavy trucks which are available, and it introduces no new technology. That doesn't mean it won't be significant when (and if) it is actually produced, but it is no miracle. PR bull doesn't do anyone any favours.

New technology is interesting. There is none in the Semi or the new Roadster.



aeroscott said:


> The Bugatti is not a super car and has no state of the art engineering.


That's sarcasm, right? It's legitimately hard to tell in some of these discussions. The Bugatti Chiron is a "supercar" - a title applied to any extreme high-performance car with a huge price tag - but it's neither a heavy truck nor a competitor to the Roadster, so it's not a rational comparison point. Tesla Motors couldn't build a single car like the Chiron if Elon's life depended on it; it is certainly state-of-the-art, as are many cars.



aeroscott said:


> It sounds like you just don't like ev's or engineering , you didn't talk about 20% less cost and the ability to do 500 miles , that's all that matters to trucking company's, except you did mention refueling but so did elon and has done it before(supercharger)


I find EVs interesting and I love engineering; these vehicle announcements are all about marketing and have nothing to do with engineering.

Musk's cost numbers are sheer fabrications of his imagination, and the range is both unproven and inadequate... but it isn't surprising, since anyone could predict that based on the size of the battery and a 2 kWh/mile consumption rate. Superchargers and the required (for the Semi) Megachargers are useless for the majority of long-haul trucking applications, particularly in the quantity which are likely to be available.

Yes, cost and operability are all that matter to trucking companies. The Semi is too expensive for them in general (although there will be exceptions), and operability is far from proven. Tesla Motors can't even built the Model 3 at all, or build cars of any model with 100% million-mile reliability, but they are promising million-mile truck operation.


----------



## aeroscott (Jan 5, 2008)

Do you think ev's , solar ,etc. are displacing hydrocarbon fuels and the reason GE's ,Peabody coal and utility's are being displaced . In fact the talking heads just yesterday said GE's stock price was due to it's dependence on utilities which have lost peak power to solar . The utilities have restricted the size of solar house installations with no pay for surplus power to home owners to limit losses.
For over 30 years the alternate energy people have warned of this displacement. 
The claims made about viability which I have made are based on the simplest of engineering . drive trains over 100 years of use, weight advantage of 5 to 1 (mpg/ton) , charging ,cost and life all demonstrated with cost falling , charging infrastructure growing and cycle life growing. 
Cars were hard trucks are easy.


----------



## aeroscott (Jan 5, 2008)

Elon didn't invent much but did design a great car and infrastructure . That's the game changer.


----------



## Duncan (Dec 8, 2008)

Elon didn't invent much - agree!

His EV contribution was that he understood something that has been well known for over 100 years 
That Sex and Fun sell cars

The other manufacturers are *still* trying to sell electric cars as "Hair Shirt" specials for people who don't like cars


----------



## electro wrks (Mar 5, 2012)

brian_ said:


> There certainly is a pattern in these trucks (including the Nikola Motor proposal): the cab extends forward and narrows, which is good for aerodynamics and is made easier by the lack of need for engine access or clearance for the top of an engine. Unfortunately, it makes access to the door more difficult, leading to this bizarre enter-by-the-back-door system.
> 
> I have no idea why this truck wasn't shown months - or years - ago, since there is nothing very new in it. I suppose Tesla Motors just needs some good press to offset the continuing Model 3 production disaster.
> 
> ...


Musk is definitely the supreme marketing showman. His timing and method of releasing these two vehicles was just brilliant. Think of the new sports car as the first Tesla delivered on Tesla's own electric truck! Only time will tell if he's a great visionary, or a desperate business person throwing everything onto the wall to see what sticks!

Techwise, are you sure about the other single speed drive axles available from other suppliers? Here's a close look at the Tesla units: https://www.teslarati.com/tesla-semi-four-motor-drivetrain-gearbox/ 
They look like conventional banjo style live drive axles. Right down to the air bag and shocks suspension(with trailing arms?). The innovative part is the four removable center sections(two for each axle), the "pumpkins".

Each pumpkin has a Model 3 super efficient, hybrid switched reluctance motor, driving a wheel independently. I'm guessing this means no mechanical connection between the wheels. The differential action, traction control, and some braking must all be taken care of electronically. I think Musk said the axles are just a single speed-amazing. Notice there are only 2 wires going to each pumpkin, so the inverter/controllers must be built-in, in typical Tesla fashion.

Practically speaking, I think you're overlooking the point to point use of a vehicle like this, in the near future. Automatic charging at both ends during loading and unloading times, driver-less or one driver in a road train. Heck, robots loading and unloading. 24 hour operation with little or no noise and fumes stirring-up the neighbors. As someone who works on trucks sometimes, I look forward to the day when I don't have to work on noisy stinking diesels!


----------



## aeroscott (Jan 5, 2008)

Nice find Electro Wrks,
SRM motors ,800 volt batteries,multiple motors .wow ,Iv'e been talking about the advantages of this for years . nice to see.


----------



## PhantomPholly (Aug 20, 2008)

This was a nice bit from the article above:

"_He also noted the drivetrain’s safety benefits, adding “the truck will automatically stop jackknifing because it has independent motors on each wheel and it will dynamically adjust the torque on each wheel so that jackknifing is impossible. Your worse nightmare is gone with this truck._”

That will save lives...


----------



## brian_ (Feb 7, 2017)

*Suspension*



electro wrks said:


> They look like conventional banjo style live drive axles. Right down to the air bag and shocks suspension(with trailing arms?).


Yes, although the video does not show the suspension clearly, it does appear to be a common off-the-shelf heavy truck air suspension. That means trailing arms with airbags behind the axle beam, and either some sort of upper arm and track bar, although the cheapest ones use leaf springs as spring beams, instead of separate upper arms. The motor and gearbox assemblies are really bulky, so they get in the way of the usual lateral track bar; in the shaky monochrome video I was unable to pick out any lateral location device, but there must be something.

It's interesting that they didn't go with independent suspensions for the drive axles, as Nikola Motors did. They're readily available.

Arguments in favour of independent drive-axle suspension

high unsprung mass of beam axles with motors and gearboxes mounted to them (avoided by independent suspension)
high-tech appeal (to match the "we're better in every way" attitude)
proven improved traction (over bumps in real roads) of better suspension

Arguments in favour of beam axle suspension

cheaper
mechanically simpler (which is why it is cheaper)
cheaper
traditional, and so more readily accepted by the trucking industry
cheaper


----------



## brian_ (Feb 7, 2017)

*Roadster unveiling timing*



electro wrks said:


> Musk is definitely the supreme marketing showman. His timing and method of releasing these two vehicles was just brilliant. Think of the new sports car as the first Tesla delivered on Tesla's own electric truck! Only time will tell if he's a great visionary, or a desperate business person throwing everything onto the wall to see what sticks!


All of the business publications have clued into Musk's plan: Tesla Motors is counting the days before they run out of cash, so the Roadster was shown to start a new round of collecting deposits to fund current operations while running up a liability for the future. This time, they went all-out and are asking for a $250,000 deposit on a "$200,000+" vehicle... expecting to raise a quarter-billion dollars in operating funds from their favourite type of customer (deep pockets, gotta-be-first).

That doesn't mean there's anything wrong with the car... this is just about one motivation for the "surprise" unveiling.


----------



## brian_ (Feb 7, 2017)

*Semi motor and transmission configuration*



electro wrks said:


> Techwise, are you sure about the other single speed drive axles available from other suppliers? Here's a close look at the Tesla units: https://www.teslarati.com/tesla-semi-four-motor-drivetrain-gearbox/
> ... The innovative part is the four removable center sections(two for each axle), the "pumpkins".
> 
> Each pumpkin has a Model 3 super efficient, hybrid switched reluctance motor, driving a wheel independently. I'm guessing this means no mechanical connection between the wheels. The differential action, traction control, and some braking must all be taken care of electronically. I think Musk said the axles are just a single speed-amazing. Notice there are only 2 wires going to each pumpkin, so the inverter/controllers must be built-in, in typical Tesla fashion.


I don't think a single-speed transmission is "amazing"... it's the easiest possible solution, and that's how everyone does light EVs. Current production heavy transit buses using axle-mounted motors (such as ZF's AVE 130) have single-speed reduction gearing. The Mercedes urban transport truck uses a variant of the same ZF system. The BYD heavy truck tractor (yes, the same type of vehicle which Tesla is promising), the T9, uses a 241 hp motor for each drive axle... presumably mounted on the axle because there is no other reasonable way to mount one motor per axle.

Yes, two motors have been mounted to each axle housing, with no mechanical connection between the wheels. That's what the electric bus axles do (more compactly, since they fit under low-floor buses in portal axles), and that's what Wrightspeed does in their heavy truck units. The Nikola Motors prototype positions the motors the same way as Tesla (because it's obvious), but uses independent suspension so that mirror-image double gearbox assembly is mounted to the frame instead of to an axle beam (as in the Telsa Semi).

The gearboxes are presumably Model 3 units, with the differentials removed, placed in pairs by rotating one 180 degrees about the vertical axis to swing it to the other side of the axle line, and each shifted to the non-motor side to interleave with each other and move the motors closer to centre. They do appear to have 15:1 gearing, according to the label. That seems perhaps a little high for a Model 3, but way too low for the tire size of the truck; at over a metre in diameter, an 11R24.5 only turns 479 revolutions per mile so 15:1 gearing would only give 7800 rpm at 65 mph... perhaps that's in addition to another reduction stage in the axle housing, or it's just a leftover label from the Model 3 which doesn't apply to the Semi. Personally I like this layout - even for a car - but it's hardly innovative... even I thought of that setup years ago.

Separate motors per wheel does mean electronically managing differential action. I'm disappointed that it has taken so long to get to this point; when I first saw a Model S drive unit it looked like it had two motors (due to the cylindrical inverter housing), and it was a letdown to learn that it was just one motor and an old differential. On the other hand, separate motors were inevitable, it's the obvious choice with large motors (and is used by most currently available heavy truck and bus EV drives), and it is the approach used by the electric-only axle of cars such as the BMW i8, the Acura NSX, MDX, and RLX, and the Rimac concepts. It avoid the mechanical complexity of a differential, and the wasteful use of friction brakes to control distribution of drive torque between wheels. It's good... it's just not innovative. To underline this, large (over 300 ton payload) diesel-electric mining trucks have used one motor per driven wheel for decades.

Everyone puts the inverter adjacent to the motor, and the trend is to tighter and tighter integration of housings to minimize cable length and connections; it's a good idea, it's just not a Tesla Motors idea. For example, a second-generation Leaf inverter is more closely integrated with the motor (using copper bars to interconnect) than a Model S inverter and motor combination (which has short internal cables).

The use of the Model 3 motors is sensible (just use four of what you have most recently put into production), and again nothing new.


----------



## brian_ (Feb 7, 2017)

PhantomPholly said:


> This was a nice bit from the article above:
> 
> "_He also noted the drivetrain’s safety benefits, adding “the truck will automatically stop jackknifing because it has independent motors on each wheel and it will dynamically adjust the torque on each wheel so that jackknifing is impossible. Your worse nightmare is gone with this truck._”
> 
> That will save lives...


Nice, but not so special.

Tractor-trailer rigs typically jacknife at speed (distinguishing this from tight low-speed maneouvers) because the trailer brakes lock up. ABS has been available on heavy trucks for many years to fix this.

Differential drive torque on the tractor's wheels can certainly help as well; this is electronic stability control, and has been required by federal law in North America for years on all passenger cars. Individual drive motors are a nice way to do this, but certainly not required - all those engine-driven cars out there do it with the brakes.

Cars and light trucks intended for towing have additional logic to handle the trailer. Since the Tesla Semi is just a truck, and does not include a special trailer (with drive motors on the wheels) as part of the system, it will be doing exactly the same thing as a common pickup truck towing a travel trailer (caravan). A difference might be that if Tesla tries to do it with just the motors, they won't be able to use the front wheels; the front wheels are very useful in stability control.


----------



## brian_ (Feb 7, 2017)

*Semi / Model 3 motors*



electro wrks said:


> ... Each pumpkin has a Model 3 super efficient, hybrid switched reluctance motor...





aeroscott said:


> Nice find Electro Wrks,
> SRM motors...


Maybe not. The Model 3 motors have been described as 3-phase AC synchronous permanent magnet (not switched reluctance) in everything else I've seen. Even if the rotor design takes advantage of flux path manipulation by a designed pattern of reluctance, it would be a hybrid of permanent magnet and *synchronous* reluctance, using a sinusoidal 3-phase stator winding, not a switched design. This motor design is the Tesla Motors move to join nearly all other EV manufacturers, instead of continuing with induction motors for their new models.

Unfortunately, "switched" and "synchronous" both start with the letter "s", causing some confusion.


----------



## brian_ (Feb 7, 2017)

*Heavy truck trailer?*



electro wrks said:


> Here's a close look at the Tesla units: https://www.teslarati.com/tesla-semi-four-motor-drivetrain-gearbox/


Thanks for this video link - this is the first one I've seen which reveals that the show truck doesn't have a functional trailer attached. The truck's fifth-wheel hitch is a conventional unit, but the first glimpse of a tiny little kingpin assembly on the trailer which could barely tow my travel trailer safely suggests that the demo trailer must be a lightweight empty box that can't carry anything, The framework visible at the end confirms that it's just a trailer-shaped box that allows people to duck underneath to see the truck.

I do understand not hauling a 30-ton loaded trailer out onto the stage, but a real (albeit empty) commercial trailer would have bought some credibility. They showed two Semis (one high-roof sleeper, the other a low-roof day cab), so they could have unhitched one to fully reveal the drivetrain.

Hmmm... shouldn't this truck autonomously hitch and unhitch? At the very least, they should have shown the driver standing outside beside the hitch, controlling the hitching and unhitching with his smartphone.


----------



## brian_ (Feb 7, 2017)

electro wrks said:


> Practically speaking, I think you're overlooking the point to point use of a vehicle like this, in the near future. Automatic charging at both ends during loading and unloading times...


Good point. For routes of this type the charging is much more easily managed. Although Musk's comments certainly imply that the Semi is the future of all heavy trucking, perhaps he didn't say specifically long-haul.

That's clearly the most suitable type of route for BYD's T9, which has much shorter range than planned for the Tesla Semi (simply due to battery capacity), and is already in production.
Canadian Grocer Electrifies Fleet
Loblaw unveils first fully electric Class 8 truck, setting the stage for zero-carbon commercial grocery deliveries in Canada

This is also the type of route that works well for natural gas fuel (as a diesel alternative), which has largely been a flop.


----------



## aeroscott (Jan 5, 2008)

Theirs a big difference between stability control in a IC and EV .The IC is much slower to up power and jerky , slow and not precise . My experience driving a AMG CL 5.5 and a Tesla P85D in insane mode . This will be compounded with the mass of the IC truck gear plus the slow responding air brake system.
LTI has been using SR motors for many years and has more traction drive experience then anyone.


----------



## brian_ (Feb 7, 2017)

aeroscott said:


> Theirs a big difference between stability control in a IC and EV .The IC is much slower to up power and jerky , slow and not precise .


Sure, but not much of stability control is by throttle change - brakes respond quickly enough. Yes, it can be even better with drive motors; my point is that claiming that Tesla's technology makes stability control possible is nonsense.



aeroscott said:


> This will be compounded with the mass of the IC truck gear plus the slow responding air brake system.


Mass of what gear? The rotational inertia of the engine has nothing on the truck's inertia, and the electric truck will be even heavier than the engine-driven truck.

Air brakes are not so slow to respond when each wheel's hardware is controlled by an electronically managed valve, as it is with heavy truck ABS. You're not waiting for pressure changes to propagate down the length of the plumbing.



aeroscott said:


> LTI has been using SR motors for many years and has more traction drive experience then anyone.


Again, the Model 3 / Semi motors are not switched reluctance; that is what LeTourneau Technologies Inc - now a part of Joy Global - is experienced in.


----------



## electro wrks (Mar 5, 2012)

Perhaps you don't understand me. What I find amazing about the Tesla drive axles is their simplicity and the adapting to existing conventional designs. Any fleet service department will instantly recognize and understand the traditional banjo and pumpkin layout of the Tesla axles. If that "million mile service" thing doesn't work out for the motor and gears in the pumpkin, it would be very easy and quick to change it out. The tires/wheels don't even need to be pulled off. Brake and wheel bearing work: also easy conventional stuff. No massive hub motors to deal with.

The Wrightspeed has an unnecessarily complex 4 speed transmission built into each axle AFAIK and BTW, separate inverter boxes.

The Nikola platform: again an unnecessarily complex IRS and motor/gear units crammed together in what looks like a hard-to-work-on mess.

And, by far the most amazing aspect of the Tesla layout I see, is the possibilities of easily using it in smaller(single axle, class 6 and 7) trucks. Including, down the line, in DIY conversions. Just like the gold mine of salvaged Model S and X parts people are collecting now.


----------



## aeroscott (Jan 5, 2008)

Brian, The rotating mass of engine transmission and dive line plus the very slow throttle response .This moves with the wheel and the wheel is retarded by that mass. If the traction control is called to act , that means momentum is starting to build,say the back end is moving out, the longer it takes to respond the more likely to get to the point of no return. If you ever drifted a car and think about what has been going on you would understand momentum building past the point of no return .
Why would you say , that I said Tesla makes stability control possible.EV's make it much better.
Do you have experience in engineering ,building,operating machines ,probably not You need to lose the attitude. 
*DIY Electric Car Forums*


----------



## Kevin Sharpe (Jul 4, 2011)

*Re: Roadster unveiling timing*



brian_ said:


> This time, they went all-out and are asking for a $250,000 deposit on a "$200,000+" vehicle...


Not exactly... the Tesla Roadster is $200,000 with a $50,000 deposit, and the Tesla Roadster Founders Series is $250,000 with a $250,000 deposit.


----------



## brian_ (Feb 7, 2017)

electro wrks said:


> Perhaps you don't understand me. What I find amazing about the Tesla drive axles is their simplicity and the adapting to existing conventional designs. Any fleet service department will instantly recognize and understand the traditional banjo and pumpkin layout of the Tesla axles. If that "million mile service" thing doesn't work out for the motor and gears in the pumpkin, it would be very easy and quick to change it out. The tires/wheels don't even need to be pulled off.


The use of familiar suspension will be reassuring - I agree that it's a legitimate advantage of the traditional live beam axle design.


----------



## brian_ (Feb 7, 2017)

On the other hand...


electro wrks said:


> Brake and wheel bearing work: also easy conventional stuff. No massive hub motors to deal with.


Working on the hubs will be just like any other truck, with any of the existing or proposed designs, even the independent suspension. You don't touch the differential of a conventional truck axle to work on the hubs, and you won't touch the motors or gearboxes of the electric trucks to work on their axles.

The motors in the bus axles are not really hub motors; that is, the hub is not part of the motor. They're just motors mounted on the axle beam as far outboard as possible, with the output of each reduction gearset feeding into the hubs. Servicing these will be no different from servicing any heavy bus or truck axle. If the ZF product doesn't look like a familiar bus axle, perhaps due to the widely spread air springs, have a look at the portal axle in modern transit buses such as ZF's AV 133.


----------



## brian_ (Feb 7, 2017)

electro wrks said:


> The Wrightspeed has an unnecessarily complex 4 speed transmission built into each axle AFAIK and BTW, separate inverter boxes.
> 
> The Nikola platform: again an unnecessarily complex IRS and motor/gear units crammed together in what looks like a hard-to-work-on mess.


We'll see how the single-ratio thing works out. Viability in cars is based on the fact that there is excess power available, so having less than full power available at low speeds is not an issue - they are traction-limited. Tesla is counting on the real truck (rather than the 5-second 0-60 animation) having sufficient low-speed performance without a lower gear ratio, and that might work out. Perhaps one reason to target highway trucks (rather than urban delivery or vocational applications) is that they spend most of their time in the top 3/4 of their operating speed range, and thus in the constant-power regime of the motors.

While I don't consider Nikola Motors a serious contender, their drive units look no more complex in mounting and packaging than Tesla's. The independent suspension is more complex than a beam axle, especially a beam axle with no propeller shaft (because the motor is on the axle), but that's almost unrelated to the electric powertrain: both beam axle or independent suspensions are available for and used on driven and non-driven axles, steering and non-steering axles, in engine-driven and electrically driven trucks. Of course the most common heavy vehicle choice is beam axles for everything, with the most popular independent application being steered and non-driven front axles (like the Tesla Semi).

I was surprised that Tesla didn't go for independent drive axle suspension, just for the techie wow factor.


----------



## brian_ (Feb 7, 2017)

And now for the *DIY* electric car content... 



electro wrks said:


> And, by far the most amazing aspect of the Tesla layout I see, is the possibilities of easily using it in smaller(single axle, class 6 and 7) trucks. Including, down the line, in DIY conversions. Just like the gold mine of salvaged Model S and X parts people are collecting now.


I don't think you'll want these axles in a Class 6 truck, any more than you would want current Class 8 drive axles in Class 6 trucks. They're simply far too heavy; if using the all of the gearing they'll also likely be geared too low for highway use with smaller tires. Of course the design approach will translate to smaller units, and you could build a custom axle to use just the motor/gearbox drive units, but the unsprung weight of two drive units on the axle beam of a truck at half the Class 8 axle load will give terrible ride and handling... that's probably one reason why Wrightspeed's smallest models don't use axle-mounted motors.

If you really want, you can replace the differentials with spools in two small Tesla Model S/X drive units, turn one around, bolt both to an axle beam, and make your own version right now.


----------



## brian_ (Feb 7, 2017)

*Re: Roadster unveiling timing*



Kevin Sharpe said:


> Not exactly... the Tesla Roadster is $200,000 with a $50,000 deposit, and the Tesla Roadster Founders Series is $250,000 with a $250,000 deposit.


Yes, "only" a thousand of them are being offered at the extra-high price and massive deposit of the Founders Series. It's still a scheme to raise cash to cover the current problem. Even the $50,000 deposit for non-Founders units - which pushes your delivery date back by an unknown period while the Founders units are delivered - is a cash-now/liability-later scheme.

Also, none of those screen shots promise or even suggest that the price of the Roadster Founders series $250,000. Even the regular $200,000 price is not guaranteed, and there's no indication of how this model would be equipped. I doubt anyone will ever buy a Roadster 2 for US$200,000, but that's only a guess.


----------



## brian_ (Feb 7, 2017)

aeroscott said:


> Brian, The rotating mass of engine transmission and dive line plus the very slow throttle response .This moves with the wheel and the wheel is retarded by that mass.


Yes, just like the rotating mass of the Tesla Semi's motors and transmissions. Brakes have no problem handling this; not surprising, since they can exert more torque at the wheel than the powertrain.



aeroscott said:


> If the traction control is called to act , that means momentum is starting to build,say the back end is moving out, the longer it takes to respond the more likely to get to the point of no return. If you ever drifted a car and think about what has been going on you would understand momentum building past the point of no return .


Yes, been there, done that. 



aeroscott said:


> Why would you say , that I said Tesla makes stability control possible.


Sorry for the misunderstanding, but I didn't say that. It is Tesla Motors which presents this stuff as if they are handing down miracles.



aeroscott said:


> EV's make it much better.


Yeah, I said that.



aeroscott said:


> Do you have experience in engineering ,building,operating machines ,probably not You need to lose the attitude.
> *DIY Electric Car Forums*


Yes. Nothing electric yet, although I have considered converting my Spitfire.

My attitude is that Elon Musk is not some sort of supernatural being, Tesla Motors does not perform miracles and it's actions and choices should not be accepted unquestioningly, and there is a massive amount of valuable technology available - created by any people in many countries working for many companies over centuries - to draw from.


----------



## Kevin Sharpe (Jul 4, 2011)

*Re: Roadster unveiling timing*



brian_ said:


> I doubt anyone will ever buy a Roadster 2 for US$200,000, but that's only a guess.


I believe you'd have no problem suing Tesla given they state "Total vehicle price is $200,000" during the Roadster reservation process. Obviously they'd have to be in business for you to collect but I don't believe the fan boys will let them fail in the foreseeable future.

Personally I don't like Musk (who I've met twice) or Tesla (who I purchased a Roadster from in 2010) but I'm really glad they both exist today. Tesla push the boundaries and make electric cars aspirational for many


----------



## brian_ (Feb 7, 2017)

*Re: Roadster unveiling timing*



Kevin Sharpe said:


> ... I'm really glad they both exist today. Tesla push the boundaries and make electric cars aspirational for many


I agree with that.


----------



## electro wrks (Mar 5, 2012)

brian_ said:


> We'll see how the single-ratio thing works out. Viability in cars is based on the fact that there is excess power available, so having less than full power available at low speeds is not an issue - they are traction-limited. Tesla is counting on the real truck (rather than the 5-second 0-60 animation) having sufficient low-speed performance without a lower gear ratio, and that might work out. Perhaps one reason to target highway trucks (rather than urban delivery or vocational applications) is that they spend most of their time in the top 3/4 of their operating speed range, and thus in the constant-power regime of the motors.


A clue that may explain how Tesla gets away with a single speed is in the video. One of the motor/gear housings is marked(as you pointed out)15:1(rear tandem axle?). If you keep looking, another one is marked 23:1(front tandem axle?). If this is the case, again,amazing!


----------



## brian_ (Feb 7, 2017)

*Re: Roadster unveiling timing*



Kevin Sharpe said:


> I believe you'd have no problem suing Tesla given they state "Total vehicle price is $200,000" during the Roadster reservation process. Obviously they'd have to be in business for you to collect but I don't believe the fan boys will let them fail in the foreseeable future.


Tesla's Roadster Reservation Agreement states:


> *3. Order Process*
> While this Reservation secures your approximate delivery priority, it does not constitute	the purchase or order of a vehicle. When the start of production for your Reservation nears, we will ask you to configure your vehicle. Tesla will create an order for your vehicle and you	will receive a *Purchase Agreement* indicating the purchase price of the vehicle, plus	estimates of any applicable taxes, duties, transport and delivery charges, and any other applicable fees. If you proceed with the order, we will apply your Reservation Payment towards the order payment.


The "Total vehicle price" is not a commitment by Tesla Motors... and I wouldn't expect one. Other companies don't commit to final prices at this sort of advance reservation, either, because it would not be prudent.


----------



## brian_ (Feb 7, 2017)

electro wrks said:


> A clue that may explain how Tesla gets away with a single speed is in the video. One of the motor/gear housings is marked(as you pointed out)15:1(rear tandem axle?). If you keep looking, another one is marked 23:1(front tandem axle?). If this is the case, again,amazing!


Good catch  ; I only noticed one ratio. 

Different ratios may not be so useful. The more extreme ratio must still be low enough to keep that motor from over-speeding at the highest road speed (since there are no clutches or neutral gear configurations available). The less extreme ratio then seems relatively pointless (it wouldn't help low-speed performance), although Tesla has in the past talked about shifting drive power between dissimilar front and rear power units. In this case, with identical motors, they would be directing power to the motor which is in the more efficient operating point.

23:1 seems reasonable - 12,000 rpm at 65 mph - but I haven't seen the operating speed range of the Model 3/Semi motors yet. Tesla has said before that induction motors are better for high speeds (than synchronous PM motors), so it seems inappropriate to assume the same speed range as the Model S/X motors.

In all of this, of course, the two gearboxes on the same axle must have the same reduction ratio.


----------



## electro wrks (Mar 5, 2012)

brian_ said:


> And now for the *DIY* electric car content...
> 
> 
> I don't think you'll want these axles in a Class 6 truck, any more than you would want current Class 8 drive axles in Class 6 trucks. They're simply far too heavy; if using the all of the gearing they'll also likely be geared too low for highway use with smaller tires. Of course the design approach will translate to smaller units, and you could build a custom axle to use just the motor/gearbox drive units, but the unsprung weight of two drive units on the axle beam of a truck at half the Class 8 axle load will give terrible ride and handling... that's probably one reason why Wrightspeed's smallest models don't use axle-mounted motors.


This is not the case. State and Feds limit a tandem axle set-up, like on the Tesla, to 34,000#, combined, and a single axle to 20,000#. This means the single is generally larger and heavier than each individual axle in a tandem set-up. I know this because I have a truck with one of these single axles, and have had to wrestle it around in the shop! The gear ratio could be a problem. But, it looks like Tesla has given us at least a couple of ratios to choose from-check the video again!


----------



## electro wrks (Mar 5, 2012)

brian_ said:


> Good catch  ; I only noticed one ratio.
> 
> Different ratios may not be so useful. The more extreme ratio must still be low enough to keep that motor from over-speeding at the highest road speed (since there are no clutches or neutral gear configurations available). The less extreme ratio then seems relatively pointless (it wouldn't help low-speed performance), although Tesla has in the past talked about shifting drive power between dissimilar front and rear power units. In this case, with identical motors, they would be directing power to the motor which is in the more efficient operating point.
> 
> ...


Brian, you really need to think outside the box here. You're sounding like someone who didn't get in early with Tesla stocks, or is worried about their short sells. I'm pretty sure the Model 3 does not have an induction motor. It has a hybrid switched reluctance or, as you suggested, a hybrid synchronous reluctance motor. Someone else needs to confirm this.

This being said, who's to say Tesla only uses one type of motor on its semi-truck axles?!! Again, keep it outside the box!


----------



## brian_ (Feb 7, 2017)

electro wrks said:


> I'm pretty sure the Model 3 does not have an induction motor. It has a hybrid switched reluctance or, as you suggested, a hybrid synchronous reluctance motor.


Yes, that's what I said... at least twice. 

It is _because_ the Semi motors are not induction that the motor speeds in existing Tesla models cannot be assumed to be the same for the Semi.



electro wrks said:


> This being said, who's to say Tesla only uses one type of motor on its semi-truck axles?!!


Elon Musk. He said that it uses Model 3 motors. The company is proud of the level of use of existing parts - which is a good thing - so they have brought it up more than once.


----------



## electro wrks (Mar 5, 2012)

*Re: Heavy truck trailer?*



brian_ said:


> Thanks for this video link - this is the first one I've seen which reveals that the show truck doesn't have a functional trailer attached. The truck's fifth-wheel hitch is a conventional unit, but the first glimpse of a tiny little kingpin assembly on the trailer which could barely tow my travel trailer safely suggests that the demo trailer must be a lightweight empty box that can't carry anything, The framework visible at the end confirms that it's just a trailer-shaped box that allows people to duck underneath to see the truck.
> 
> I do understand not hauling a 30-ton loaded trailer out onto the stage, but a real (albeit empty) commercial trailer would have bought some credibility. They showed two Semis (one high-roof sleeper, the other a low-roof day cab), so they could have unhitched one to fully reveal the drivetrain.
> 
> Hmmm... shouldn't this truck autonomously hitch and unhitch? At the very least, they should have shown the driver standing outside beside the hitch, controlling the hitching and unhitching with his smartphone.


I suspect this is not an over the road standard trailer. I'm sure it's a custom trailer with a low deck so the new sports car could be driven off on a low ramp for maximum dramatic effect. Should we expect anything less of Mr. Musk?


----------



## electro wrks (Mar 5, 2012)

One problem with the Tesla Semi, as others have pointed out, may be the battery weight penalty. If the 10,000# battery weight is true, it's replacing a much lower weight of ICE parts. This lost weight carrying capacity might be a factor if a user is consistently running weight limited loads.


----------



## aeroscott (Jan 5, 2008)

Just talked to my long haul truck driver buddy. Tesla offered 2 trucks for a supper deal to the company he drives for and he is going to buy one too .Supper price,for bata testing. 
He thinks the traction control is game changing . 
He does oversize loads. Lots of experience.


----------



## electro wrks (Mar 5, 2012)

I wonder if the batteries are included in the million mile service life? Say 400 miles between charges into a million is 2500 charge cycles. Sounds doable. How long would the average truck take to do a million miles? Correct me if I'm off-say 10 years. Also, probably doable assuming current battery life numbers.

aeroscott, I bet a lot of number crunching like this is going on about this truck in many company headquarters, as we write.


----------



## aeroscott (Jan 5, 2008)

A friend who drives for Walmart says 125,000 miles/ year sounds high to me.


----------



## electro wrks (Mar 5, 2012)

125,000 miles per year? OK, 8 years to reach a million miles. even more doable.


----------



## aeroscott (Jan 5, 2008)

Al (first driver) says he does a lot of hills ,so regeneration will payoff great.


----------



## Kevin Sharpe (Jul 4, 2011)

Bloomberg - "Tesla’s Newest Promises Break the Laws of Batteries"

https://www.bloomberg.com/amp/news/...s-newest-promises-break-the-laws-of-batteries


----------



## Duncan (Dec 8, 2008)

Hi Kevin

My Volt pack is 14 Kwh and less than 100 kg - 2011/12 - that works out as 140 whr/kg
According to that graph we are not meant to hit that until 2019
The current (as of over a year ago) Tesla units are over 150 wh/Kg
That graph show us reaching 150 wh/kg in 2021

So the weight graph is miles out - we are at least 5 years ahead of that

The cost graph is also stupid - Chevy was SELLING batteries for $250/kwh in 2011

Again out by about 5 years 

Why do people publish this rubbish when a few minutes research will show that it is nonsense

I see the same on things like solar panels people doing articles quoting prices for commercial projects that are higher than I was quoted as a private individual four years ago


----------



## aeroscott (Jan 5, 2008)

They ignoring Tesla's change from the 18650 to bigger cell giving something like 20-30% better energy density. The averaging any numbers with industry
doesn't address the huge advantage they have in cost ,R&D and packaging


----------



## Kevin Sharpe (Jul 4, 2011)

In terms of current production vehicles the Tesla 100D pack is ~170 Wh/kg (102400 Wh / 603 kg) and the Alta Motors pack is ~188 Wh/kg (5800 Wh / 31 kg).

Obviously the Tesla Model 3 will see further improvements but afaik we don't have any definitive weight or capacity figures nor do I think it's *really* a production car today 

I agree the data used is out of date but I found the article interesting in terms of what Tesla believe they can deliver in a couple of years time... for example, a 200kWh battery that is presumably lighter and smaller than the current 100kWh battery


----------



## Karter2 (Nov 17, 2011)

aeroscott said:


> They ignoring Tesla's change from the 18650 to bigger cell giving something like 20-30% better energy density. The averaging any numbers with industry
> doesn't address the huge advantage they have in cost ,R&D and packaging


 The change to 21700 cell size has not increased the energy density, infact it has reduced it slightly !


----------



## Kevin Sharpe (Jul 4, 2011)

A different take on the Tesla event


----------



## aeroscott (Jan 5, 2008)

Duncan said:


> Hi Kevin
> 
> My Volt pack is 14 Kwh and less than 100 kg - 2011/12 - that works out as 140 whr/kg
> According to that graph we are not meant to hit that until 2019
> ...


I didn't check , I too have a Volt pack .

The best part of their bs is about the charging and how they could ever get that kind of power to the pack! I invented a new idea use 10 chargers,LOL da. 
Anything to delay the demise of hydrocarbons.


----------



## aeroscott (Jan 5, 2008)

Karter2 said:


> The change to 21700 cell size has not increased the energy density, infact it has reduced it slightly !


That's not what I remember from reading about it.


----------



## brian_ (Feb 7, 2017)

Given the obvious concern with weight - which I think we all agree is valid - it seems a little strange that they chose to mount conventional dual tires on the drive axles. Readily available wide-base singles with the same load capacity are lighter (the wide single tire is lighter and the dual pair, and the 14-inch wide wheel is lighter than two standard wheels) and as a bonus have lower rolling resistance.

Nikola Motors put wide-base singles on their prototype, and Mercedes has them on the drive axle (there's also a non-driven tag axle with narrower single tires) of the Urban eTruck prototype.

Wide-base singles are more popular on trailers than on tractors, and more popular in Europe than in North America, so they're not really mainstream here, but they have been around and proven - even on North American tractor drive axles - for many years.

I don't know if the old dual setup is to reassure truckers that the Semi is as conventional as possible, or it is just nowhere near finished under the flashy bodywork.


----------



## Kevin Sharpe (Jul 4, 2011)

How The Tesla Roadster Hits 60 MPH In 1.9 Seconds!


----------



## brian_ (Feb 7, 2017)

Kevin Sharpe said:


> How The Tesla Roadster Hits 60 MPH In 1.9 Seconds!


Did he say anything useful? I can't stand listening to that guy chatter while he waves his hands in front of a whiteboard for a quarter of an hour.


----------



## Kevin Sharpe (Jul 4, 2011)

brian_ said:


> Did he say anything useful?


The segment on tyres was very interesting and builds on some of his previous work. He also reminds us that nothing about this car has been independently verified


----------



## Kevin Sharpe (Jul 4, 2011)

Interesting article comparing the 'old' and 'new' Roadster (here)

"It’s unlikely that the new Roadster will manage anything close to the original Roadster’s weight. The aforementioned 200kWh battery will be heavy – very heavy. The current 100kWh pack in a Model S weighs more than 1,000lbs (453kg). Even with the next couple years of battery advancement, it seems likely to me that the pack alone will be close to 2,000lbs (907kg). Then add three electric motors, seats, a (probably aluminum) chassis, and a body which felt like it was made of either carbon fiber or fiberglass, and this car seems like it will be, at minimum, in the mid-high 3,000s or possibly above 4,000lbs (1814kg)."


----------



## aeroscott (Jan 5, 2008)

Kevin Sharpe said:


> Interesting article comparing the 'old' and 'new' Roadster (here)
> 
> "It’s unlikely that the new Roadster will manage anything close to the original Roadster’s weight. The aforementioned 200kWh battery will be heavy – very heavy. The current 100kWh pack in a Model S weighs more than 1,000lbs (453kg). Even with the next couple years of battery advancement, it seems likely to me that the pack alone will be close to 2,000lbs (907kg). Then add three electric motors, seats, a (probably aluminum) chassis, and a body which felt like it was made of either carbon fiber or fiberglass, and this car seems like it will be, at minimum, in the mid-high 3,000s or possibly above 4,000lbs (1814kg)."


 Isn't the Bugatti about 4000 lbs.and the MB SL AMG are over 4000 lbs.
4X4 adds a lot of weight , more in a ic then ev.
Nice point on traction control too.


----------



## Duncan (Dec 8, 2008)

The Battery weight
If a 100 Kwhr battery including structure and armour weighs 1000 lbs 
Then doubling the capacity need NOT double the weight

Locating the battery so that the cars structure shields it and provides structural integrity means that you could get 200 kwhr for not a lot more than 1000 lbs

Even if you still have an armoured battery the armour could weigh exactly the same so you could end up with a 200 kwhr battery for 1500 lbs


----------



## brian_ (Feb 7, 2017)

As Aeroscott noted, extreme performance cars packed with every possible feature are now routinely very heavy; the examples from Bugatti and Mercedes are typical. The original Tesla Roadster was an electrified Lotus Elise; the Elise is an excellent example of modern lightweight sports car design, although of course the EV version is heavier. Another example of a current lightweight would be the Alfa Romeo 4C.

Battery-electric and hybrid cars are not light. The most extreme current Porsche is the hybrid 918, which weighs about 1700 kg, or 3700 lb.

The new Roadster is a high-power four-seater. I don't think anyone knowledgeable in automotive design would expect it to be lightweight.

It presumably has an aluminum structure, like all other Tesla Motors cars. If there are no rumours of an external supplier contracted to build the structure, it seems very unlikely that it would be composite (such as carbon fibre).

Here's a bizarre statement for you:


> Back on the Bugatti Chiron for a moment, in the presentation on the Tesla Semi, Musk mentioned that the Semi has the same Cd as a Bugatti Chiron. This was somewhat of a meaningless comparison – supercars are meant to be a little bit draggy, because if they slipped through the air too well, then they’d lift right up off the road. This is why you see wings (aka spoilers) and active aerodynamic features on cars which are meant to travel at such high speeds. The Roadster does include one of these, as you can see in the press shot below.


I find it strange that anyone got close enough to understand that coefficient of drag for the truck and for a Bugatti Chiron are not relevant to compare, but missed the reason: "supercars" such as the Chiron do not create more drag because "_if they slipped through the air too well, then they’d lift right up off the road_"; they create drag as an undesired and unavoidable consequence of producing downforce.

Cars like the Chiron produce downforce so they can corner at high speed; any Tesla car only has to go fast in a straight line (or a banked test track), so it doesn't need downforce; whatever it gets from the flat bottom and rear diffuser will be enough. The Semi will never go fast, doesn't need any downforce at all, and surely will not create any.


----------



## Karter2 (Nov 17, 2011)

Duncan said:


> The Battery weight
> If a 100 Kwhr battery including structure and armour weighs 1000 lbs
> Then doubling the capacity need NOT double the weight
> 
> ...


 There are 8256 cells in tesla 100kWh pack, each cell weighing 49gms.
https://www.teslarati.com/inside-look-tesla-p100d-battery-pack-teardown/
So a 200kWh pack would need 2x8256x 0.049 = 809 kg (1780 lb) of cells alone.
That is without any of the buss plates , cooling system, connectors, BMS systems, etc etc...let alone the casing.
I dont see how a 200kWh pack can be less than 2000lb using current cell tech.?

EDIT..
Just noticed that a Tesla 24v, 5.3kWh module , weighs 55lb.....10.4 lbs/kW
So again , 200kWh of bare "modules" will weigh 2000+ lbs


----------



## Duncan (Dec 8, 2008)

Karter2 said:


> There are 8000+ cells in tesla 100kWh pack, each cell weighing 49gms.
> So a 200kWh pack would need 2x8000x0.049 = 784 kg (1725 lb) of cells alone.
> That is wothout any of the buss plates , cooling system, connectors, BMS systems, etc etc...let alone the casing.
> I dont see how a 200kWh pack can be less than 2000lb using current cell tech.?


By that logic the current 100 Kwhr pack could not be 1000 lbs as the structure and the armour are quite heavy

With my Volt pack the cells weigh less than half the total pack


----------



## aeroscott (Jan 5, 2008)

Thinking back a few years ago , to even be talking about similar performance
at say 500lbs heavier then it's ic counterpart . wow,heavy man.
What will come next.


----------



## Karter2 (Nov 17, 2011)

Duncan said:


> By that logic the current 100 Kwhr pack could not be 1000 lbs as the structure and the armour are quite heavy
> 
> With my Volt pack the cells weigh less than half the total pack


 Last figure i recall was 1200+ lbs , and that was for a 85 kWh pack. !
http://www.roperld.com/science/teslamodels.htm
So adding 15kWh of cell weight (140 lbs),...would mean around 1350 lbs at least for the 100kWh pack.


----------



## Kevin Sharpe (Jul 4, 2011)

Karter2 said:


> Last figure i recall was 1200+ lbs , and that was for a 85 kWh pack. !
> http://www.roperld.com/science/teslamodels.htm
> So adding 15kWh of cell weight (140 lbs),...would mean around 1350 lbs at least for the 100kWh pack.


Your estimates look reasonable to me and I have no reason to believe that Tesla had 200kWh in the Roadster prototype at the launch... if Tesla had achieved a step change in battery technology they would have revealed details, in reality their technology has already hit today's limits as Musk confirmed in relation to the Model 3.


----------



## aeroscott (Jan 5, 2008)

Larry Ellison of Oracle had Kirkhann Motor Sports build a billet Cobra.
Kirkhann's website describes the build in great detail ,a must read for any car guy. He talks about the stiffness of the chassis,racing cv shafts etc.
Just checked out his website and didn't see the build story. 
Anyway if you stack the two 100 Kwh batteries you could get a extremely stiff chassis , very important in a hipper car.
I found the book 23 chapters to download pdf file.
ch.11 half shafts . check out these . the chassis stiffness tests are near the end of the book.
WWW.kirkhammotorsports.com/book_aoe/


----------



## Karter2 (Nov 17, 2011)

Wow!..
That Cobra is some labour of love, and really puts the Tesla back into its place .
I have seen/read many Cobra reproductions but that is in a new league.
I cannot imagine the time and effort needed to put that project together,..never mind the cost.
Accelleration and top speed mean nothing when you have a piece of pure art like that wrapped around you.


----------



## aeroscott (Jan 5, 2008)

To bad they covered the work with a body. Did you read ch.11 the 1/2 shafts,10 pages with pictures .


----------



## Karter2 (Nov 17, 2011)

Yes, the shafts are engineering porn, but the body build is something else also,..real artisan work, with detail such as the stripes, ....which are not paint, but just a different surface texture in the aluminium !!


----------



## aeroscott (Jan 5, 2008)

I have always been impressed by the inner working of cars and the cobra overall shape seams short and puffy compared to 275 long nose Ferrari .
The workmanship is the finest ever. A tilt nose would have been great but not true to Cobra.


----------



## Kevin Sharpe (Jul 4, 2011)

"All last night's event did was add to Elon Musk's shopping list of things he needs to spend money on at a time when the company is having difficulty making its base vehicle (Model 3) and its equity and debt has traded off," Jeffrey Osborne, an analyst at Cowen & Co., wrote in a report Friday.

http://www.autonews.com/article/201...-fundraising-playbook-to-launch-semi-roadster


----------



## aeroscott (Jan 5, 2008)

He has a huge battery production plant that is gearing up to make far more batteries then he stated in the past. If you take the number of employees X 2000 hrs./year divide that by yearly out put you get 40 man hrs./85Kwh battery.
4hrs. would be high so 10X of stated seams more like it.


----------



## Karter2 (Nov 17, 2011)

Bear in mind the Gfactory is not working too well currently.
In order to supply the 129MWh of Powerpacks to Australia, Tesla had to get Samsung to make the cells !
129MW represents 0.25% of the Gfactories annual capacity, or less than a days production . !...so what is the story ?,.. Its not as if they are building cars faster than they predicted .


----------



## aeroscott (Jan 5, 2008)

So are you saying he will not be able to produce . Or he is a failure for not producing fast enough.
My dad said the company he worked for never got a project on projected man hours and they were the 2nd largest steel consumer in the U.S.


----------



## Kevin Sharpe (Jul 4, 2011)

How Roadster can reach 250 mph with 1-speed gearbox


----------



## aeroscott (Jan 5, 2008)

Well done, thanks for posting


----------



## aeroscott (Jan 5, 2008)

I think Tesla would use higher voltage to get more torque at high rpm.
Like 800 volts Porsche .


----------



## Karter2 (Nov 17, 2011)

Yes, with Teslas current config, the torque drops off rapidly from about 7k rpm, and the power tails off also.
His theory seems fine , but i suspect he is way off with the weight estimate at 2000 kg total. A 200kWh battery would push it way over that.


----------



## aeroscott (Jan 5, 2008)

Back emf will be compensated with volts.
If it comes out 500lbs. heavy , It's still a great machine.


----------



## Kevin Sharpe (Jul 4, 2011)

Karter2 said:


> His theory seems fine , but i suspect he is way off with the weight estimate at 2000 kg total. A 200kWh battery would push it way over that.


Agreed... he's a Tesla fanboy so you can't expect much in terms of battery reality


----------



## Kevin Sharpe (Jul 4, 2011)

Green Car Reports - Tesla Semi, Roadster battery claims prove puzzling: beyond current knowledge?


----------



## Duncan (Dec 8, 2008)

If you read that article it is busy quoting the Bloomberg numbers which a very quick examination showed to be at least 7 years out of date 

They are referencing numbers that I know could be beaten seven years ago as better than we can do today!

Add on another 7 years of steady incremental improvements to their numbers and the numbers Tesla is talking about don't seem that outrageous

WHY do ALL of the mainstream media seem to be so far behind the real world????


----------



## aeroscott (Jan 5, 2008)

time lines, " he hit me at 12 noon, the so and so . I hit him at 11:59 ,so what! That's not the point!" 
Good thing governments don't do that!LOL


----------



## PhantomPholly (Aug 20, 2008)

Duncan said:


> If you read that article it is busy quoting the Bloomberg numbers which a very quick examination showed to be at least 7 years out of date
> 
> They are referencing numbers that I know could be beaten seven years ago as better than we can do today!
> 
> ...


Lots of reasons Duncan, and I agree with you on this. Some do it on purpose to discredit. Some (most) are simply lazy. And, most human beings cannot grasp the difference between linear and exponential change, or the fact that life is exponential not linear. The ideologues at MIT Technology Review hyperventilate in every article about Climate Change, then refuse to publish any news article which might mean the end of AGW in just a few years even though the discovery (a potential flow battery invented right there at MIT for which the materials cost is only $1/Kwh, which would be a total game changer).

We live in a world where people are bored and seek power, and have no interest whatsoever in the simple truth.


----------



## Kevin Sharpe (Jul 4, 2011)

Real Engineering - The Truth About The Tesla Semi-Truck


----------



## brian_ (Feb 7, 2017)

Kevin Sharpe said:


> Real Engineering - The Truth About The Tesla Semi-Truck...


Well that was vastly better than the usual video prattling! 
I like the associated web-based calculator, for us to try our own assumptions.

The calculated battery mass is several tons. For comparison, I ran across some interesting information from Energy.gov's Fact #620: April 26, 2010 Class 8 Truck Tractor Weight by Component today:
*Weight of Truck Components on a Typical Class 8 Truck Tractor*

Wheels and Tires
1,700 lbs, 10% of total
includes a set of 10 aluminum wheels, plus tires

Chassis/Frame
2,040 lbs, 12% of total
includes frame rails and crossmembers, fifth wheel and brackets

Drivetrain & Suspension
2,890 lbs, 17% of total
includes drive axles, steer axle, and suspension system

Misc. Accessories/Systems
3,060 lbs, 18% of total
includes batteries, fuel system, and exhaust hardware
note that this would include some components still needed in an electric truck, such as the compressed air supply system

Truck Body Structure
3,230 lbs, 19% of total
includes cab-in-white, sleeper unit, hood and fairings, interior and glass

Powertrain
4,080 lbs, 24% of total
includes engine and cooling system, transmission and accessories

Total: 17,000 lbs
Source: National Academy of Sciences, _Technologies and Approaches to Reducing the Fuel Consumption of Medium and Heavy-Duty Vehicles_, prepublication copy, March 2010, p. 5-42.
... or graphically:









The Tesla Semi has conventional components for these categories:

Wheels and Tires	1,700 lbs
Chassis/Frame	2,040 lbs

It has a fancy cab, not likely to weigh any less than a conventional cab:

Truck Body Structure	3,230 lbs

It has conventional axles and suspension, but with motors and gearboxes instead of differentials, so they will weight more than this:

Drivetrain & Suspension	2,890 lbs

So that multi-ton battery has to weigh no more than this to avoid cutting into payload:

Misc. Accessories/Systems	3,060 lbs
Powertrain	4,080 lbs
With current technology, that target would be missed by a wide margin.


----------



## brian_ (Feb 7, 2017)

For the complete opposite to Tesla's slick marketing with minimal facts, try these guys and their truck which actually drives around on the street... pulling 60,000 pounds:




Thor Truck
Like I think I've mentioned, you take common frame and chassis components, stick in a motor and really big battery, and you have a heavy and expensive but working truck... not a Miracle by Elon. 

I think it's interesting that when Tesla Motors uses off-the-shelf parts for most of the truck that shows that it's workable, but when Thor Trucks does the same thing that makes their truck a "Frankenstein". At least the Thor guys were bright enough to use wide-base single tires, although none of the article that I've read give them any credit for that.

To be fair to Tesla, their Semi does have a bit of development in it to mount the Model 3 motors and gearboxes on the axles, while Thor mounts the motor on the frame to drive a standard axle... which means they have less room between the frame rails for battery.


----------



## Kevin Sharpe (Jul 4, 2011)

brian_ said:


> For the complete opposite to Tesla's slick marketing with minimal facts, try these guys and their truck which actually drives around on the street... pulling 60,000 pounds.


Great video and wonderful to see the Thor truck driving around the streets


----------



## PhantomPholly (Aug 20, 2008)

Kevin Sharpe said:


> Real Engineering - The Truth About The Tesla Semi-Truck


Video says "if you work in mountainous areas this truck may not be for you."

They have it backwards - truck will perform BETTER as compared with traditional in mountainous areas because of better power and regenerative braking.


----------



## aeroscott (Jan 5, 2008)

Ya, didn't you know ev's only go up hill. How embarrassing for them.


----------



## brian_ (Feb 7, 2017)

PhantomPholly said:


> Video says "if you work in mountainous areas this truck may not be for you."


The comment seems to ignore the ability of regenerative braking on downhill grades to substantially compensate for the extra energy of climbing grades; however, the calculation does credit for regeneration (with a very optimistic efficiency), so perhaps the commenter just didn't explore the effect of hills objectively. The calculation is available online - anyone interested can just try it out.



PhantomPholly said:


> They have it backwards - truck will perform BETTER as compared with traditional in mountainous areas because of better power and regenerative braking.


Right - mountainous areas will not help the battery-electric truck, they just won't hurt energy consumption as much as they will a diesel, and a battery-electric truck with as much power as promised by Tesla will have a grade-climbing advantage.

There are battery-electric heavy trucks available today (such as the one by BYD); someone should do some flat-ground and mountain-area comparative testing.


----------



## PhantomPholly (Aug 20, 2008)

brian_ said:


> Right - mountainous areas will not help the battery-electric truck, they just won't hurt energy consumption as much as they will a diesel, and a battery-electric truck with as much power as promised by Tesla will have a grade-climbing advantage.


My point was that hills reduce the difference in range between a diesel and EV. That is because of (as we both pointed out) regenerative braking.

Assume a diesel and an EV have exactly enough starting "fuel" to make it up a high hill. At the top, the diesel must refuel, while the EV can continue downhill actually recuperating some of the energy spent climbing. Assume it then "retrieves" 50% of that energy. It can still climb another hill 50% as high as the first hill, then repeat the process. In theory, at 50% regeneration such a truck will have double the range in hills (Calculus - the limit as n approaches infinity of n + n*.5) as it would absent regeneration.

All the diesel will have to show for having climbed the first hill will be worn brakes coming down.


----------



## Kevin Sharpe (Jul 4, 2011)

PhantomPholly said:


> Assume it then "retrieves" 50% of that energy.


I spent a month driving my Tesla ~5000 miles to Switzerland from the UK several years ago. I drove out across the relatively flat planes of Northern Europe where my energy consumption was much like it was at home. When I hit the Alps I noted that my energy consumption doubled despite using regenerative braking whenever possible.

I believe regenerative braking contributes little to real world range (not surprising when you consider the poor efficiencies of electricity generation and battery charging/discharging) and would like to see some evidence to support your 50% assumption


----------



## Kevin Sharpe (Jul 4, 2011)

brian_ said:


> There are battery-electric heavy trucks available today (such as the one by BYD); someone should do some flat-ground and mountain-area comparative testing.


Agreed... it would be helpful to see some real data.


----------



## PhantomPholly (Aug 20, 2008)

Kevin Sharpe said:


> I spent a month driving my Tesla ~5000 miles to Switzerland from the UK several years ago. I drove out across the relatively flat planes of Northern Europe where my energy consumption was much like it was at home. When I hit the Alps I noted that my energy consumption doubled despite using regenerative braking whenever possible.


Not the point. Gas vehicles increase use a bunch in mountains too - the rolling frames are roughly at parity from that perspective. The point is that anything at all that regenerative braking does to recoup that high energy usage closes the gap between what a gas car can do miles-wise vs the EV.

Maybe it isn't 50% (and probably isn't - I don't have numbers). Principle remains. If you have exactly enough gas / electricity to get up the hill and no more, the ev can go further because it can safely go down the hill and still have a little left, whereas the gas vehicle would be coasting down without power steering and would coast to a stop at the bottom of the first hill.


----------



## Kevin Sharpe (Jul 4, 2011)

PhantomPholly said:


> Maybe it isn't 50% (and probably isn't - I don't have numbers).


The impact of regenerative breaking is difficult to measure... several years ago a small group of EV enthusiasts in the UK tried to compare the efficiency of regenerative braking against coasting using two 'identical' Leafs... we couldn't measure any significant difference over 70 miles and concluded that in the real world driving style, weather, and terrain were much more important.

We need real data


----------



## brian_ (Feb 7, 2017)

PhantomPholly said:


> My point was that hills reduce the difference in range between a diesel and EV. That is because of (as we both pointed out) regenerative braking.


For this part, we're saying the same thing.



PhantomPholly said:


> Assume a diesel and an EV have exactly enough starting "fuel" to make it up a high hill. At the top, the diesel must refuel, while the EV can continue downhill actually recuperating some of the energy spent climbing. Assume it then "retrieves" 50% of that energy. It can still climb another hill 50% as high as the first hill, then repeat the process. In theory, at 50% regeneration such a truck will have double the range in hills (Calculus - the limit as n approaches infinity of n + n*.5) as it would absent regeneration.


This assumes that no energy is used to keep the truck moving, against rolling drag and aero drag; this is very far from true.



PhantomPholly said:


> All the diesel will have to show for having climbed the first hill will be worn brakes coming down.


Yes, but most of the braking needed on descents is provided by engine braking... I don't think there's all that much brake wear.


----------



## brian_ (Feb 7, 2017)

PhantomPholly said:


> Gas vehicles increase use a bunch in mountains too - the rolling frames are roughly at parity from that perspective. The point is that anything at all that regenerative braking does to recoup that high energy usage closes the gap between what a gas car can do miles-wise vs the EV.


Yes... but it's not a big gain, as Kevin has already noted. My gasoline van's fuel consumption isn't much higher in the Rocky Mountains than on flat ground, because it simply uses less fuel while descending than while climbing. The incremental improvement beyond that due to regeneration will be small.

The bigger advantage (operationally, but not in energy consumption) would likely be maintaining a higher speed on the climb, knowing that starting descents from a higher speed is more acceptable due to regenerative braking.



PhantomPholly said:


> If you have exactly enough gas / electricity to get up the hill and no more, the ev can go further because it can safely go down the hill and still have a little left, whereas the gas vehicle would be coasting down without power steering and would coast to a stop at the bottom of the first hill.


No, the gas vehicle would coast up the next hill until the gain in potential energy (from elevation) and loss of energy (to drag) balance the loss of kinetic energy (coming to a stop).


----------



## Duncan (Dec 8, 2008)

Re Re-gen
It's all down to how you drive
If you drive like a hooligan - then you get a lot of benefit 
If you drive gently then you don't

As far as the hills are concerned if they are steep enough that you have to do a lot of braking then re-gen will benefit you 
If you can simply coast down the hills and not get too fast then re-gen won't help

For a big truck and actual mountains I expect that re-gen will give major benefits - much more than for a car or van


----------



## WolfTronix (Feb 8, 2016)

For what it is worth.

I have never noticed much of an improvement with regen during highway driving, (aero losses dominate).

City driving (stop and go), regen makes a huge difference in amp-hours used.


----------



## PhantomPholly (Aug 20, 2008)

Kevin Sharpe said:


> The impact of regenerative breaking is difficult to measure... several years ago a small group of EV enthusiasts in the UK tried to compare the efficiency of regenerative braking against coasting using two 'identical' Leafs... we couldn't measure any significant difference over 70 miles and concluded that in the real world driving style, weather, and terrain were much more important.
> 
> We need real data


I would agree with more data. Still, the discussion was about mountain driving - where semis use "compression braking" as well as actual braking (all wasted energy). I would guess that regeneration might be as high as 50% if you were driving down, for example, the Pioga Pass out of Yosemite park (or similar incline). Anything you do regenerate is "free fuel."


----------



## PhantomPholly (Aug 20, 2008)

brian_ said:


> This assumes that no energy is used to keep the truck moving, against rolling drag and aero drag; this is very far from true.
> 
> 
> > Steep hills provide more than aero and rolling drag - thus the original caveat "in mountainous areas."
> ...


----------



## Kevin Sharpe (Jul 4, 2011)

Does The Tesla Roadster Really Have 7,000+ lb-ft Of Torque?!


----------



## brian_ (Feb 7, 2017)

Kevin Sharpe said:


> Does The Tesla Roadster Really Have 7,000+ lb-ft Of Torque?!


Sure, that's plausible. Any typical modern high-performance car puts out a great hundred pound-feet of torque from the engine, multiplies it by at least a few times through the transmission in first gear, then multiplies it again by a great times in the final drive gearing, resulting in a few thousand pound-feet of torque to the wheels. A Tesla is similarly geared.

This is what the video said, much less concisely  and with some basic explanation of the difference between and torque. He also confused things with his "torque multiplication" chatter, because he thinks it is a unique characteristic of hydrodynamic fluid couplings.

Quoting torque at the wheels is done to produce impressive numbers. It actually makes some sense, since it doesn't matter to the driver whether the engine runs at high speed with low torque or low speed with high torque.


----------



## brian_ (Feb 7, 2017)

PhantomPholly said:


> I don't know the exact number, but I'd guess anything over about a 4% grade / heavy load requires more than compression braking - and in any event you would never want to use compression braking if you had regen available.


I don't think so: trucks wouldn't survive mountain highways if they used the wheel brakes on every >4% descent. Engine braking (with a compression-release brake such as a Jacobs) is quite effective and is also very loud, and I haven't even noticed heavy trucks doing much on this on most Rocky Mountain descents, although I agree that some must be required at the higher grades, if constant speed is to be maintained; in many cases, they just accelerate since they crest the top at such low speed.

Between better road design and better trucks, runoff lanes are essentially obsolete on modern highways, and I haven't seen a recently-constructed one for many years.


----------



## Karter2 (Nov 17, 2011)

Back to the Semi...
Regen or not, what will make or brake the Etruck is weight , more specificly battery weight.
As someone pointed out earlier, in order to match ICE tractor weight, there is about 7000lb available for battery pack, charger, etc.
Using current best known battery (pack) energy density, 7000lb would mean about 500kWh max capacity, which even at the ambitious claim of 2kWh/mile , suggests only a 250 mile range !
In order to meet the 400 mile range target , it seems the E'semi would need to carry an extra 6000lbs of battery
To me that means our electric truck owner is either going to have to loose 6000lbs of paid freight,....or mr musk has to double his battery energy density !


----------



## Duncan (Dec 8, 2008)

I would query that 7000lbs

With current technology there does not seem to be much of a drive towards reducing the weight of the Tractor unit
I suspect that a lighter Tractor Unit would not be a good idea 

The result is that there is a lot of weight that is not actually necessary - but it just "The way that we have always done it"

Now with a battery powered unit there IS some incentive to lose that "traditional" weight or more accurately to move the weight into the battery 

Maybe not the full 6000lbs that we need - but I bet at least 4000lbs


----------



## Karter2 (Nov 17, 2011)

There is every incentive to reduce the tractor/trailor base weight, as most road regulations limit the total vehicle weight,...
... so every extra pound of chassis weight is a pound less of paying freight it can haul.
These guys are even more pessimistic (and detailed in their calculations) ..estimating a pack weight of 16-24 tons !
http://pubs.acs.org/doi/full/10.1021/acsenergylett.7b00432


----------



## Duncan (Dec 8, 2008)

But if the Tractor is too light then it can't safely tow a max weight trailer

There IS a minimum weight that is considered useful - and if you have a look at any tractor unit you can see that the construction is NOT optimised for minimum weight


----------



## Karter2 (Nov 17, 2011)

Is that a mandated minimum weight, or theoretical ?
Either way, it would be a strange decision to a truck operator to willingly forgo a ton or several of potential payload because he has a heavyier tractor than his competitors.
I dont know, but i suspect there is alot of design effort put into keeping the tractor weight down to a minimum.
A "5th wheel" is not like towing a loose trailor, you can transfer a lot of freight weight onto the tractor chassis if needed.


----------



## brian_ (Feb 7, 2017)

Duncan said:


> With current technology there does not seem to be much of a drive towards reducing the weight of the Tractor unit
> ...
> 
> The result is that there is a lot of weight that is not actually necessary - but it just "The way that we have always done it"


Really? There are some parts which are heavier than they need to be, but lighter components would be more expensive or less proven in this sort of operation.


----------



## brian_ (Feb 7, 2017)

Duncan said:


> I suspect that a lighter Tractor Unit would not be a good idea





Duncan said:


> ... if the Tractor is too light then it can't safely tow a max weight trailer


I don't think that's true, given that we are talking about a tractor for a semi-trailer. The load on the hitch provides much of the traction needed by the truck, so the truck (tractor) itself doesn't need to be heavy. The lighter the truck, the more important it will be to keep the pin position ahead of the rear axle group effective centre, to maintain an appropriate front axle load. Certainly a ton or two added to or subtracted from the truck can't be important.


----------



## Duncan (Dec 8, 2008)

brian_ said:


> Really? There are some parts which are heavier than they need to be, but lighter components would be more expensive or less proven in this sort of operation.



less proven - is the problem as nobody wants to actually bite the bullet

There is a huge amount of conservatism in this industry - nearly as much as the military

It will take a big change like the Tesla for a lot of the truck components to reflect the actual weight that is needed as opposed to the weight that they have always been


----------



## brian_ (Feb 7, 2017)

Duncan said:


> less proven - is the problem as nobody wants to actually bite the bullet


Sure, or it's just not economically viable at this point.



Duncan said:


> There is a huge amount of conservatism in this industry - nearly as much as the military


Perhaps for good reason, as trucks actually need to work reliably and effectively, unlike trendy cars.



Duncan said:


> It will take a big change like the Tesla for a lot of the truck components to reflect the actual weight that is needed as opposed to the weight that they have always been


The Tesla Semi doesn't address any of those weight issues. It has conventional structure, suspension, brakes, wheels, and tires; the fancy cab is not light. To be fair, the front suspension is reportedly independent, but there's no reason to believe that it is anything other than a conventional off-the-shelf heavy vehicle product (as commonly used on buses and military trucks). The only meaningful change that comes with this truck (the powertrain) increases weight.


----------



## PhantomPholly (Aug 20, 2008)

brian_ said:


> Sure, or it's just not economically viable at this point.


Bingo. No profit, no company.


----------

