Oh, No!

Discussion in 'Tesla' started by El Dobro, Oct 2, 2013.

  1. Trollbait

    Trollbait It's a D&D thing

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    It pierced a quarter inch of steel. With another car, that's enough force to have easily penetrated the passenger cabin and possibly skewered someone.

    We used to build cars to survive accidents. While there was some success there, unfortunetly the car got mushed up inside. Completely preventing fires do to collision is impossible. No matter how good, the engineers can not envision every scenario, and then budget constraints are a reality. So we take the best steps to preventing them, and design systems to protect the occupants when they do happen.
     
  2. daniel

    daniel Cat Lovers Against the Bomb

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    Citing the figure of 1 fire per 25,000 vehicles is complete and utter nonsense because you cannot extrapolate the probability of an event from a single instance. It is statistically insignificant. You need a large number of instances before you can infer a probability.

    And the comparison of the FM and Ford cases with Tesla is ridiculous, because in the case of GM and Ford, the fires were caused by defects in the car which resulted in spontaneous fires, with no outside intervention, while in the case of the Model S it was a severe accident that caused the fire, and the vehicle performed as designed to protect the occupant(s).
     
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  3. massparanoia

    massparanoia Active Member

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    If you want a vehicle that will be able to withstand any type of accident consider one of these:

    [​IMG]

    It is an alternative fuel vehicle, as it's gas turbine engine will run on just about anything combustible. And It's depleted uranium armor will withstand all but the mightiest of road debris.

    But seriously, I've responded to plenty of car fires in my day. If you're worried about burning alive either drive a tank or stay home. Considering how tesla said the accident happened, the debris was basically a steel sabot that penetrated the underside of the car. Much like the DU sabots these guys fire.

    Maybe the tesla is more like a tank than I thought....
     
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  4. Sergiospl

    Sergiospl Senior Member

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  5. dbcassidy

    dbcassidy Toyota Hybrid Nation, 8 Million Strong

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    You would not want to drive it off a bridge, kind of hard to break a window to get out. Also, there is no precious seconds of flotation.

    The above has happened over in Iraq.

    Crew drown as US tank topples into Euphrates | World news | The Guardian

    DBCassidy
     
  6. daniel

    daniel Cat Lovers Against the Bomb

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    ^ They're also not street legal.
     
  7. El Dobro

    El Dobro A Member

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  8. massparanoia

    massparanoia Active Member

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  9. daniel

    daniel Cat Lovers Against the Bomb

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    Lithium batteries are flammable. They are probably about a hundredth or a thousandth as flammable as gasoline. But they make the news because it's a new thing and they are rare enough to report on, compared with gasoline fires, which are so common there wouldn't be room in the paper to list them all.

    The Model S confines the fire to the battery compartment and directs the flames downward and away from the cabin. The fires also start much more slowly than gasoline fires, giving the EV occupants much more time to exit the car than the drivers of gas cars have. The Model S is still the safest car on the road. Unfortunately, humans are notoriously bad drivers and keep having accidents.

     
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  10. seilerts

    seilerts Battery Curmudgeon

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    No, it is a combination of the armor being insufficient to prevent being pierced by ordinary road debris, coupled with very low ground clearance. Tesla either needs to redesign the materials used for the armor, or add a cow catcher that deploys at highway speeds.
     
  11. massparanoia

    massparanoia Active Member

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    Is it just plate steel or some kind of composite they are currently using? Are they much lower to the ground than a "normal" sports car, such as a corvette or a Porsche?
     
  12. Trollbait

    Trollbait It's a D&D thing

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    It is an assumption that it was ordinary road debris. All reports are that it was a large piece of metal. It likely couldn't be found after the collision, or was wedged in the car.

    The ground clearance of the S is 6 inches. Which is point seven more than the Prius'. The smart air suspension can raise it to 7.3 inches, which was the only number I could find in respect to clearances. At most, IMO, it can't lower the car greater than 2 inches. That is still more clearance than the previous gen Corvette, which is 3.7 to 3.2 inches depending on model.

    The armor plate is a quarter inch thick. Thicker than anything protecting a fuel tank on another car. The battery also starts after the front. So this road debris was shaped in a manner to get under most of the frunk before it was leveraged up. Most cars would have ended up with serious damage from it. Lighter ones might have been flipped.
     
  13. daniel

    daniel Cat Lovers Against the Bomb

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    Absolutely NOT "ordinary road debris." These have been significant metallic road obstructions that would have destroyed another car, but such "ordinary" accidents don't make the news. "Fire in an EV" makes the news because it happens so seldom, and is sensational.
     
  14. massparanoia

    massparanoia Active Member

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    Are lithium batteries, particularly the ones in the tesla, pyrophoric when exposed to air? Puncturing a fuel tank on a "normal" car does not necessarily mean it will catch fire. Or is the metal debris causing a short circuit on impact?
     
  15. daniel

    daniel Cat Lovers Against the Bomb

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    The Tesla Roadster uses ordinary commodity laptop batteries. I'm not sure, but I think the S uses the same. I don't believe exposure to air is sufficient to ignite them, but puncturing the pack with a big metal object could short the cells, causing a spark, at the same time as it opens them.

    As noted elsewhere, the car is designed to contain fires within the specific block of batteries where it originates and direct the flames away from the cabin. In all three cases, it performed admirably.

    Eventually someone will die in a Model S. No car can protect you from everything, and the highways are chaotic and crowded with lunatics. When the time comes, Tesla stock will drop 15% before the facts emerge and the NHTSA reports that the car performed correctly and no car could have prevented the death in a similar accident. If the accident involves a fire, the press will have a field day and the anti-EV crowd will be exultant. The only reasons I don't drive a Model S is because it's a much bigger car than I need and my Tesla Roadster suits me better.
     
  16. seilerts

    seilerts Battery Curmudgeon

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    For the record, a receiver hitch caused the most recent incident. Around here, I see those from time to time on the road, making it ordinary road hazard crap, and, no, I can't see how one could flip a car.

    No one is arguing that it is not a safe car, but there is a growing argument that something needs to be done about either the armor and/or adding a fire suppression system.

    The model S cells are different from the Roadster, 3.1 ah vs 2.2 ah in the same form factor, and supposedly these are automotive-grade cells instead of commodity laptop ones...I am 100% positive that someone will correct me if I am wrong.

    Okay, back to my hole...
     
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  17. massparanoia

    massparanoia Active Member

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    I'm guessing that there is only so much r&d you can do in a lab/computer and you can't account for all real world situations that might occur. I suspect that tesla will perform some "fix" to account for the fires.

    I'm still waiting patiently for my 200 mile range $25,000 EV....
     
  18. daniel

    daniel Cat Lovers Against the Bomb

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    I think Tesla is saying 2016 (?), and $30,000 (base price after any federal tax credit still in place.) So I think that 2017 is a good bet. That price for that range will require some more advances and/or cost reduction in batteries to achieve.

    We are at the dawn of a new technology. The first telephone was not all that great, and the first color TV had really peculiar colors.
     
  19. Trollbait

    Trollbait It's a D&D thing

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    IIRC, one of reports said it was a fender off a semi trailer for the first fire. Three foot lengths of 2 inch steel tube with various jutting metal ends isn't normal road debris. If it is something that warrants someone risking life and limb to remove from the road, it isn't normal.



    Tesla expects a fire in an accident to be as common as in a gasoline vehicle, which is less than a tenth or hundredth of a percent in all crashes. The S is under this.

    Came across this: http://fire.nist.gov/bfrlpubs/fire07/PDF/f07065.pdf
    "FMVSS 301 [covers fuel system integrity] has reduced the risk of impact-induced fires due to fuel tank rupture,
    despite the increase in the numbers of automobiles in use. However, the overall vehicle fire death rate has
    remained relatively constant over the past few decades, at least partially because of a ten fold increase in
    the amount of combustible materials (especially plastics) used for interior and exterior applications."

    And this: National Vehicle Fire Statistics | Chandler Law Group
    "· Also according to the NFPA, 33 car fires are reported every hour across the country, with one person per day dying in a car fire accident in the years between 2002 and 2005.

    · According to the National Fire Protection Association, there were 258,000 vehicle fires in 2007 and 385 deaths. There were 1,675 injuries.

    · There is a vehicle fire every 96 seconds in the United States."

    If a fire suppression system is warranted for the S, it is warranted for all cars on the road.
     
  20. El Dobro

    El Dobro A Member

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    Don't give the government any ideas. :eek:
     
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