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Analyst: Tesla Semi Prototypes Live Up to Performance Claims

Discussion in 'Semi' started by TMC Staff, Dec 19, 2017.

  1. TMC Staff

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    Morgan Stanley auto analyst Adam Jonas said Monday that his firm has talked to early testers of the Tesla Semi who say the impressive performance specs offered for the truck are real. XPO Logistics has been testing prototypes for the last 18 months, according to Jonas. The company praised Tesla for living up to its...
    READ FULL ARTICLE
     
  2. Electroman

    Electroman Well-Known Member

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    I don't think there was much doubt on the electric motor capabilities, although getting affirmation from an independent entity always helps.

    i think the question in everyone's mind is range and speed of charging
     
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  3. Brando

    Brando Active Member

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    Doing your own calculations - seems a website worth bookmarking/watching

    Real Engineering

    7 min. review/calculating battery needs for semi


    real engineering channel
    Real Engineering
     
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  4. Electroman

    Electroman Well-Known Member

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    There is a CMu research paper that was used in the video above:

    Performance Metrics Required of NextGeneration Batteries to Make a Practical Electric Semi Truck

    which has some nice equations that you can plug in various variables - Weight, Cd, battery energy density, range etc. - and then arrive that how much payload you can carry for what distance.

    That paper, dated May this year, concludes there is no way you can make a Semi with any decent range and acceptable payload capacity.

    Now Tesla claims they can. That all depends on two variables - Cd and cell energy density. There has been no independent verification on that. So unless that happens, I think it is wise to be skeptical.
     
  5. BerTX

    BerTX Supporting Member

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    I'll bet they have no clue as to the real goal, which is long convoys of trucks on AP running with 24" between each one. That extends range by a LOT.
     
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  6. Brando

    Brando Active Member

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    Chinese are coming to US. Making America great again? Anyway, thought you'd find interesting. March 2017. Perhaps someone can re-post at a better forum location. It may already have been posted, sorry if duplicate.
     
  7. Laban

    Laban Member

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    Didn't read the paper but we do have "real" numbers to use. I'll translate this post for you:

    TeslaClubSweden.se • Visa tråd - Hur mycket väger teslas lastbil

    Estimated weight of the drivetrain of a regular diesel Semi:

    Engine, gearbox, cooling, Ad-blue ... : 7050 lbs

    A 1000 kWh battery pack requires 55 000 (2170) cells with the current technology energy density. The 2170 cell weighs 61 gram which means that the total cell weight is 3360 kg / 7392 lbs.

    The case on a 85 kWh pack weighs ~200 kg / 440 lbs. More cells should lead to a lower case:cell weight ratio, stacked cells (Roadster ?) and so forth. We'll use 5 *200 kg -> 1000 kg/2200 lbs.

    This means that the drivetrain on the electric Semi weighs around 2500 lbs more then it's diesel counterpart - 7392 + 2200 - 7050 = ~2500 lbs.

    The post ignores the weight of the motors + gearbox on the Tesla Semi, or rather "weight of the motors + gearbox ~= weight of the rear axle of a regular Semi". Not sure that i agree with this so i'll use the weight of the Rimac motor + gearbox as a comparison.

    Single-speed gearbox = 22 kg
    183 kW continuous/327 kWh peak motor = 59 kg.

    (22 + 59) x 4 = 324 kg / 712 lbs. Might have to be a bit heavier, it's a Semi after all. We don't need a differential though (see image below) so perhaps a total of 500 lbs in additional weight.

    That means a total of ~3000 lbs disadvantage for the electric drivetrain.

    Is it possible to save this weight on the chassis and or other parts of the Semi ?

    A diesel Semi has to be able to handle the torsional forces that the engine transfers to the chassi, the Tesla Semi doesn't have this problem since the motors are mounted directly on the rear axle(s), or perhaps instead of the rear axle (differential + drive shaft).

    Compare this:

    [​IMG]

    With:

    [​IMG]

    Torsional forces:



    Screen Shot 2017-12-24 at 06.20.16.png

    It also doesn't need the same amount of sound proofing.

    The other thing to consider is the weight vs volume usage of a Semi. The statistics for Sweden is 59.5% weight vs 81% volume on average.
     
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  8. Pricee2

    Pricee2 Member

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    You need to add the weight of two 125 gal fuel tanks and their fuel. Adds about 2000 lbs to the diesel truck.
     
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  9. Electroman

    Electroman Well-Known Member

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    Huh? Then it's only fair to consider the electrons weight too on a fully charged Semi battery.

    I would say it's a washout.
     
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  10. Pricee2

    Pricee2 Member

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    I have an 18650 on my desk and will shake the electrons out and weigh them on my bathroom scale. Will get back to you with the results soooon.
     
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  11. VT_EE

    VT_EE Active Member

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    Yes, I hear it’s a huge amount of electrons, which will add hundreds of pounds when the battery is full;)
     
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  12. Laban

    Laban Member

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    Not sure if the fuel + fuel tanks was part of the 7050 lbs or not.

    It'll be interesting to see what the specifications will be for the european version of the semi. 60 ton vs 36 ton max weight and the fact that the length limitations might require a cabover + truck-trailer combination rather then semi-trailer:

    [​IMG]

    My brother runs a trucking business and one of their trips is hauling groceries from Umeå to Kiruna (the globally infamous route), 370 miles one-way, the truck sometimes and up going ~1000 miles/day. This is with cooling of the groceries in the summer and heating in the winter which by itself uses quite a bit of fuel (separate AC units running on diesel), always max weight - 60+ tonnes. And -20C or colder is not that uncommon here in the winter time.

    Charging might not be a big issue since the loading/unloading of the groceries takes ~2h but it will need a large battery to get a 370 miles range under these circumstances. The diesel is close to twice the price here so making the truck a little bit more expensive is not a big problem.
     
    • Informative x 1
  13. SwTslaGrl

    SwTslaGrl Member

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    #13 SwTslaGrl, Dec 26, 2017
    Last edited: Dec 26, 2017
    In contrast to Norway in Sweden they are building a lucrative monopoly with Eon and local utilities partnering with Clever, pricing charging at 5SEK/kWh. The spot price was 0.09SEK/kWh in 2015. This together with the requirement for private persons to set up a LLC to install solar will push the adoption of sustainable energy solutions back by tens of years in Sweden /rant off
     
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  14. jkn

    jkn Member

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    Key words: 'current technology energy density' should contain words 'in production'. I believe Tesla already has higher energy density cells. Production starts after years(?) of testing.
     
  15. jkn

    jkn Member

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    Sweden has solar energy when it is not needed and does not have it when needed.
    Solar energy production in Finland 2017.3 .. 2018.1 from Etusivu

    Screenshot-2018-1-18 Aurinkovoima.png
     
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  16. Laban

    Laban Member

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    True, Elon has said that it takes ~5 years from ”cell working in lab” to mass production at a Tesla applicable scale.

    True, but we do have a big battery (hydro power) and the opposite of solar when it comes to wind power. We get 2-3x more energy from wind in the winter.
     
  17. Brando

    Brando Active Member

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    To avoid double posts see below thread from SEMI Forum - here is a teaser of video clips

    Why DAIMLER and GM even Cummings so slow into SEMI market?
    Here are two interesting perspectives - will Tesla be allowed to dominate electric SEMIs?

    Daimler Benz to build 500 SEMIs in 2 years vs Tesla 10,000. Daimler can produce a thousand ICE trucks in a day but the losses that come with current iterating of their electric trucks make current products only "loss leaders" that cannot be sold at scale without damaging the company.

    Tesla vs GM vs Mercedes-Benz - some perspectives of why Tesla so far ahead.

    GM electric concepts since 60s and EV1 (1996-2002?) gets crushed. Standard Oil schemed with GM and Firestone to eliminate electric Trolleys to increase sales of buses & autos.
    General Motors streetcar conspiracy - Wikipedia

    2017 GM half hearted effort with the Bolt reflects an effort to say doing something, but losing reported $10,000 per Bolt and only supplying <24,000 Bolts makes it a compliance car for CARB. GM effort in electric is poorly thought out and executed. With Mercedes and Ford spending billions it maybe hard on GM if their effort level does not change. GM sold Opel to PSA Europe and got ~$2 billion in cash returned to shareholders vs. investing it in electric cars or battery plants.

    2 million mile Semi? Disruption described by "Tesla Fan Insight"
     
  18. jkn

    jkn Member

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  19. jkn

    jkn Member

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    Wind is better during winter, but not very good when cold weather comes:
    Wind power generation

    Finland does not have mountain lakes to store energy for weeks. (This time weather will change soon.)
     
    • Informative x 1
  20. avoigt

    avoigt Active Member

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    • Informative x 2

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