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Lightning/Roadster comparison

Discussion in 'Electric Vehicles' started by SteveF, Aug 13, 2008.

  1. SteveF

    SteveF Member

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    Oh boy. A car for about a quarter million dollars that will handle like a truck with its in-wheel motors. I can hardly wait.
     
  2. Finkenbusch

    Finkenbusch Member

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    #2 Finkenbusch, Aug 13, 2008
    Last edited: Aug 13, 2008
    Concerning the price-range, there are more expensive projects underway in the US - see the Ultimate Aero EV
    [​IMG]
    (^click on the picture^)
    Dont overlook that SSC company hold still the world record for selling the world fastest production car today - and you will like, its US build.


    Regarding the stunning beautiful british "Lighning"

    [​IMG]

    (^click on the picture^)
    The truck handling, you mentioned, with in-wheel motors may be a double sword knife indeed - has to be tested on the track.

    Experts claim that the four wheel individual power supply to the wheels has so much benefits on curvy roads (thats where the Teslas are naturally mostly driven for fun & tested) that it outweighs the (theoretical drawback of) higher unspung masses on race tracks - at least on public roads with a speed limit of 90 miles thought that has to be weightet against each other.
     
  3. dpeilow

    dpeilow Moderator

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    Check out the FAQ on the Mini prototype that uses the same motors:

    http://www.pmlflightlink.com/motors/hipa_faq.html

     
  4. Finkenbusch

    Finkenbusch Member

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    #4 Finkenbusch, Aug 13, 2008
    Last edited: Aug 13, 2008
    There are more very interesting links to the company PML Flightlink, you mentioned delivering the underlying Lightning technology.

    If this claims become only partly true - Tesla is looking pretty old-fashioned - especially the logical use of a battery / super-capacitor combo (used and proven as reliable in many public transport / metro systems in Europe) for close to 90% effectivity regenerative braking is very attractive.

    More about Electric Lightning Technology:
    NanoSafe™ from Altairnano Inc.


    The dashboard the company offers for EV as of the shelf product today (including SAT navigation) would have done well on the vanilla conservative Tesla dashboard.

    Click pictures below
    [​IMG][​IMG][​IMG]

    [​IMG]
     
  5. DaveD

    DaveD EVs Kick Gas!

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    Ah, so those are new-fashioned, innovative bricks acting as chocks to keep the PML Flightlink Mini from rolling? I'm all for innovative solutions, but they have be complete solutions when it comes to life-safety issues like not rolling into oncoming traffic. Relying completely on regen braking doesn't work; the vehicle will move on a sloped surface.
     
  6. Finkenbusch

    Finkenbusch Member

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    #6 Finkenbusch, Aug 13, 2008
    Last edited: Aug 13, 2008
    Maybe - you could use the supplied hand-brake in case - but thats not the point.

    The point is that the car uses capacitors to recuperate the kinetic energy (not changing into chemical energy and back as if a battery where in place) and has a range of 1.000 Kilometers.
    Kinetic energy is (very powerful - hit your head with the wall at 10 km speed and find out) used for example in big server-farms where the bridge as flywheel-concepts the time the diesels comes up in case of a grid failure.
    Especially in the city you get largely extended milage as in stop & go traffic a enormous amount of kinetic energy is continuously build up and trashed - in that case to a capacitor which uses this energy for the next start - without hassling the battery.

    Capacitors are very good at taking and delivering high loads in very short time - a field in which batteries struggle and heat up quickly.
    So why Tesla is not giving that logical combo battery & capacitor a try is beyond many experts.

    Knowing that the many metro system uses exactly that configuration since years.
     
  7. SteveF

    SteveF Member

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    It will be interesting to see how the Lightning handles in comparison to the Tesla Roadster on curvy roads at "normal" speeds. Time will tell.

    And sure the quick-charge battery technology in the Lightning is a great wiz-bang feature, but for my purposes, 99% of my usage of the Roadster will have it home happily charging in my garage overnight. In other words, not at all worth double the price of the Roadster for that feature, or whatever "extras' the Lightning has.

    But I will grant you that it's a great looking car.
     
  8. dpeilow

    dpeilow Moderator

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    http://www.pmlflightlink.com/motors/hipa_drive.html

    http://www.pmlflightlink.com/motors/hipa_faq.html

     
  9. Joseph

    Joseph Member

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    I don't know anything about PML regen systems, but I'll tell you what I do know.

    There's a guy around here in South Florida who has an AC Propulsion Ebox. As you probably know, Tesla Motors uses AC Propulsion technology for their invereter and regen system. I have met this Ebox owner numerous times, and I know for a fact that despite the car's very strong regen (at first, it's alarming) his car needs to use the brakes to come to a complete stop, otherwise it'll roll. Maybe PML has got this problem sorted out, but the Ebox, which uses technology similar to that in the Roadster, does not.

    Besides, does anyone recall Tesla (I think it was Eberhard who told us this, maybe on his blog) that regen needs to be limited because too much gives the car unpredictable driving characteristics, or could even make you lose control. It was noted that this was a problem with the tzero.
     
  10. Finkenbusch

    Finkenbusch Member

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    #10 Finkenbusch, Aug 13, 2008
    Last edited: Aug 14, 2008
    Its not the matter that regen is used at all or if it works till full stop but how you store / use that regained energy.

    - the key is that the energy is best stored to a cool capacitor (95% effectivity) and not converted (very uneconomical) into chemical energy - a battery cannot take that load in that short time and heats up (waste energy) instead of doing what it should do - store.
     
  11. deenko

    deenko Member

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    I believe that there are several reasons why tesla did not use "super caps" to store the energy from regenerative braking.

    one. The Pem is a highly modified version of ACP's design. Since ACP did not use super caps, Tesla also did not. For a first product, they might have decided to stay with what they knew worked.

    two. Under the current design, there really is no room to add the circuitry for the caps.

    three. engineering trade offs. So the trade off is to just regen the batteries and a lower efficiency rather than add weight and engineering cost to make a more efficient system. There is a lot to be said for keeping it simple. Yes stop and go acceleration is hard on any storage system. Loosing about 10 to 15% more energy just during braking can be considered an acceptable loss. When you look at a person's average driving habits, and areas where you loose energy, loosing more energy due to a less efficient regen system is actually an easy trade off compared to the added weight. With the current regen in the roadster, braking is no where near the area where efficiency can be improved, much less see the best benefit.

    four. Tesla's core competency is the ESS, or large integration of many small cells. A conservative approach is to stick with what you know.

    five. Cost. If it was cheap enough, versus the benefit. I am sure that many EV/Hybrid vehicles would use them, not just a few cases. I am not talking about all commercial applications, but rather the consumer car market.

    six. The roadster is a performance car. Weight is crucial to everything. If you are driving the car hard, regen is not enough. Too much regen is bad for handling. Nothing beats normal brakes under performance situation, and you will probably not care about regen at all in this case. Remember, the roadster is primarily about being an electric SPORTS car. If you want the best possible efficient system, measured by range, cost, carbon foot print, etc. Then take public transportation.

    seven. The roadster has an efficiency in the 90's overall in terms of converting the stored energy in the ESS to kinetic energy. Compared to what normal people are used to, ICE tends to be about 25% at best. A Hybrid is somewhere in between depending on many factors. As a result, a slight change in the drivers habits will yield a huge improvement on range in the roadster. This might be the best reason not to make one part of the car, such as regen, more efficient when there are other area that can be improved.

    Just my 2 cents.
     
  12. malcolm

    malcolm Active Member

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    #12 malcolm, Aug 14, 2008
    Last edited: Aug 14, 2008
    And they now know quite a bit:

    Look what we have had to do to bring a new car to market (a partial list):
    • Engineer a custom motor, and develop the manufacturing process to assemble it
    • Design and build a custom motor dynamometer for motor development. (Off-the-shelf dynos can’t handle the rpm range of our motor, and can’t run backwards (for testing regen)
    • Set up a factory to assemble the motor
    • Engineer the power electronics & software that powers and controls the motor, and charges the batteries
    • Design a whole new kind of battery system, with manufacturing processes to match
    • Perform several iterations of safety testing and resulting design changes on the battery system
    • Set up a factory to assemble the battery system
    • Develop a custom transmission
    • Develop the software-controlled shifting algorithm for the transmission
    • Develop and model a chassis that works with our drivetrain and our vehicle weight
    • Design and develop a new body using carbon fiber, a relatively difficult material to work with
    • Developing a federally compliant bumper system capable of withstanding low speed impact without sustaining damage
    • Perform aerodynamic testing and tuning of the body
    • Develop the car’s interior, integrating the airbag and steering column systems carried over from Lotus. This includes developing and testing new electrically heated seats, new console, new shifter technology, new instrumentation and displays, etc.
    • Develop electrically driven heating and air conditioning, integrated with the battery system cooling
    • Create a new charging standard and get regulatory approvals for it (All previous standards are obsolete, using components that no longer exist, and charging at too low a rate.)
    • Set up and sort out the manufacturing processes and quality standards for the entire car
    • Find suppliers and negotiate prices for all components of the car, and test all components for quality and suitability. Note that we are too small for many suppliers who sell to the big guys – they won’t even talk to a little company like Tesla Motors.
    • Prove that every single part of the car meets all legal requirements – a process called homologation (Gotta love that word.)
    • Perform safety testing on the car, as well as on individual subsystems (This means building and crashing quite a few cars!)
    • Perform extended durability testing on the car, as well as on individual subsystems
    • Create a support infrastructure (including service centers) for our customers
    • Source spare parts for everything replaceable on the car, and arrange logistics for these
    • Get licenses to transport, manufacture, and sell cars and subassemblies in all appropriate jurisdictions
    • Create this website, and proofread all website content
    • Begin planning for our second car, taking advantage of the technology and lessons learned from the Tesla Roadster
    • Staff an entire company and create the infrastructure necessary to do all the above
    • Raise the money necessary to fund all of the above
    Teslamotors - think

    On the subject of ultra-capacitors, two years ago the view was this:-

    Ultracapacitors are not plug-in replacements for batteries mainly because their energy density is so low. Today’s ultracapacitors store around 1% of the energy of today’s batteries and the resulting car would have around 1% of the range. They do however deliver very high power density and are excellent for applications needing high power and low energy.

    Another difficulty with ultracapacitors is that their voltage drops steeply (exponentially in fact) with state of charge. This means that we would need a fairly sophisticated high-power switching power supply to normalize the voltage to the motor, which isn’t impossible, but is definitely tricky and costly.

    None the less, I do think that new high-energy ultracapacitors may one day be the right answer for electric cars, just not now. Nobody makes ultracapacitors with anywhere near the energy density or pricing needed. That’s why they are not used in any consumer electronics yet. But when ultracapacitors are ready for prime time, we will be all over them.

    Tesla Motors - think

    I think that's a good indicator. Once capacitors start making serious inroads into powering consumer electronics / electric drills etc etc, they'll be worth another look. The present ones do not seem to be much use in capturing energy - whether from regen or from the socket on the wall.
     
  13. Finkenbusch

    Finkenbusch Member

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    #13 Finkenbusch, Aug 14, 2008
    Last edited: Aug 14, 2008
    Thank you for your technical valuable contribution malcom & deenko.

    Indeed you have mentioned some interesting points - lets see how we stand in the EV development end 2008.

    And how long a list of achievements will be then from Toyota (Prius), BMW, Mercedes Benz and the other contenders.

    I have not idea how long this list will be - certainly it will not incorporate items which are not only of the shelf productc but standard if not old-timers as own development.

    I like most your quote:

    • Find suppliers and negotiate prices for all components of the car, and test all components for quality and suitability.
    Great - I thought that is the basis any capitalistic system works - now I find Tesla has developed that brilliant and until today unknown business strategy - thanks - the world would be poorer without that find.
    Try to get a copyright on that

    Not bad also your point:

    • Staff an entire company and create the infrastructure necessary to do all the above
    • Raise the money necessary to fund all of the above.


    I thought that is the core basis any commercial company exists upon.
    Thanks for sharing that breathtaking find with a wider audience.

    Compared to the today still drivable 1909 Baker Electric car

    the revolutionary Telsas achievements mentioned are relative relative.
    The Bakers Edison batteries are over 100 years old and are still working today!
    - think
     
  14. vfx

    vfx Well-Known Member

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    Regardless of available technology Martin has pointed out that the regulating powers that be simply will not allow a car on US roads without mechanical brakes.

    Nothing a couple of million dolllars of lobbying would not cure over time.
     
  15. WarpedOne

    WarpedOne Supreme Premier

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    >> So why Tesla is not giving that logical combo battery & capacitor a try is beyond many experts.

    Experts by your standards maybe but not by mine.

    Tesla's ESS does NOT limit regen performance so why on Earth should they spend money and other RD resources on supercaps? To fix the problem that ain't there?

    It's much more prudent to use that money to add some more batteries and get more range, higher max power and lower overall stress on batteries.
     
  16. Finkenbusch

    Finkenbusch Member

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    #16 Finkenbusch, Aug 14, 2008
    Last edited: Aug 14, 2008
    You still have not got that this very tiny unimportant aspect is not the point.
     
  17. Finkenbusch

    Finkenbusch Member

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    Not everybody shares your opinion punching fun at in-wheel motors
    - actually there are studies underway describing exactly what I meant.
    And guess what - the study is based on a Lotus Elise

    Lotus-Eigne-2.jpg
     
  18. SteveF

    SteveF Member

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    OK, they were good batteries for the time, and they have lasted. But the maximum obtainable speed was, and remains, 25mph. I think I'll take the Tesla ESS, thank you, as I much prefer the Roadster's performance. Relative relative.
     
  19. Finkenbusch

    Finkenbusch Member

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    #19 Finkenbusch, Aug 15, 2008
    Last edited: Aug 15, 2008
    The streets, by the time the


    1909 Baker Electric car
    [​IMG]


    was rolling, where not paved either.
    So any speed beyond 25 mph would have sent the car to the pond - a computer was science fiction then.

    That car drives with its original Edison batteries today

    What I meant is that the nowadays "revolutionary achievements" (as full-mouthed claimed by Tesla) get smaller as closer one looks.
    You cannot buy any product today (besides original swiss watches) which will guaranteed still work in 100 years.
    From nowadays batteries there will not remain a chemical trace then - the Edison batteries probably will work in 100 years from now still...
    GM has enormous troubles guaranteeing their future customers of their ill fated VOLT, that the batteries last for 10 years.
    Edison won already tenfold and still going strong:)

    Good old times / technologies where in some fields good indeed :)

    And battery technologies developments since then remains (given the timeframe of 100 years) basically invisible
     
  20. malcolm

    malcolm Active Member

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    #20 malcolm, Aug 15, 2008
    Last edited: Aug 15, 2008
    Demand a product that is DESIGNED last 100 years??? Why on earth would you want to do that? Unless you want to be able to embarass your grandchildren with a bizarre bequest.

    Actually, I can see you doing that.

    Two points: I think the manufacturers of mobile products would disagree with you there. Secondly, if you fitted that old car with newer batteries it would obviously benefit from their improved energy density and power density. In short it would go further and faster. Sure the batteries wouldn't last 100 years, but we'll be on super-caps by then.

    They won't last 100 years either, btw. But of course long before that you'll have moved on to extolling the virtues of some other up-coming technology and tut-tutting about some future company's reliance on "old-fashioned" supercaps.

    Basically Fink, you only have two comments: 1) If it's old and it still works, it's brilliant and today's manufacturers (i.e. Tesla) should be ashamed. 2) If it's on a lab bench, it must be the future and ergo - it's brilliant and today's manufacturers (i.e. Tesla) should also be ashamed.

    But the same "criticisms" could be aimed at Lightning, Venturi, Aptera, Th!nk, Fisker etc etc.

    You can always accuse any company of not learning enough from your armchair-edited version of the past, or equally not turning on a dime to embrace the latest techno-advance you've just found on Google.
     

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