Model S fatal accident/fire

Discussion in 'General' started by David Green, May 8, 2018.

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  1. Martin Williams

    Martin Williams Active Member

    Well, the best statistics I can find are that only 3% of vehicle collisions (ICE cars) result in a fire.

    On the basis of Tesla accidents so far, 75% of them have burned. Assuming they are about as safe as ICE cars in terms of going on fire, the probability of this happening is (0.03)x(0.03) x(0.03)x (0.97) = 0.000026 or 1 in over 38,000.

    Note that I have not changed the subject at all, but merely put the argument on a quantitative basis.

    The sample is tiny, but it is not looking good for Tesla cars surviving crashes without going on fire. Pushmi declares:

    - as usual without any supporting evidence.

    The actual facts clearly imply the exact opposite!
     
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  3. Martin Williams

    Martin Williams Active Member

    I would add that diesel cars are even less likely to burst into flame after an accident. Diesel oil is very similar to cooking oil in the way it burns. It will burn with a wick, but dropping a lighted match into it a container of it will simply result in the flame going out.
     
  4. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    Being "in poor taste" has certainly never stopped your endless campaign of EV-bashing and Tesla-bashing FUD, now has it?

    All while pretending innocence, repeatedly claiming you're "really" an EV supporter. About as convincing as a KKK member claiming he's not a bigot.

    :confused: o_O :rolleyes:
    WOW!

    This lie will be so obvious to everyone that I assume you're just trolling. Maybe you are so clueless that you think such obvious FUD will fool someone. Fortunately for everyone but you, nearly all the Gentle Readers here are considerably smarter than you.

     
    Last edited: May 10, 2018
  5. Martin Williams

    Martin Williams Active Member

    For the nth time, I am all for Electric Vehicles, but for numerous reasons do not believe batteries are the way to power them. I believe the hydrogen fuel cell is better.

    Why is this so difficult for you to understand? I'd have thought it clear enough for even the dimmest numpty to grasp.

    Until these crashes, it hadn't occurred to me that they might be dangerous. Perhaps it's just bad luck - entirely possible albeit unlikely - but it isn't looking very good from that point of view either.
     
  6. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    No, clearly you're setting a new standard for numptyism. You are too dim a numpty to realize that almost nobody is so brain-dead as to believe your constant stream of FUD and B.S. Especially not when you keep repeating the same obvious B.S. over and over!

    Just how dim can a Tesla-bashing numpty get, anyway? You're setting a new standard!

    When confronted with being wrong, Martin deflects, denies culpability, ignores, changes the subject, takes jabs at Tesla and repeats the lie again a day or two later.

    Just like this.

     
    Last edited: May 10, 2018
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  8. Martin Williams

    Martin Williams Active Member

    There have been four fatal accidents which are currently under investigation. Three of them have involved fires. The NFPA figures for car fires after collisions is 3%. Make what you can of this.

    It may be just me of course but this site has become extremely slow today. I am fed up with Pushmi trying to paint me as a troll and can't be bothered waiting for more abuse so I'm going to bed. Goodnight
     
  9. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

     
  10. bwilson4web

    bwilson4web Well-Known Member Subscriber

    If the battery cell is deformed, it can cause a short across the plastic separator. Once shorted, the discharge can the cell and generate gas until it fractures the cell and ignites the electrolyte.

    FYI, an excellent example of repurposing a Model S battery pack to a boat with a lot of good technical details:


    Bob Wilson
     
    Last edited: May 10, 2018
  11. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    When it comes to outright bald-faced shameless lying, you don't mess around, do you Martin?

    Regarding fire hazards, I've seen various estimates of how much safer BEVs are than gasmobiles, ranging from about 3x safer to about 5x safer. I cited the 3x claim because I'd rather be conservative in my claims than exaggerate them. EV fanboys like me have no need to exaggerate or stretch the truth... in sharp contrast with serial Tesla bashing FUDsters!

    A relevant quote from a March 2018 article:

    There have been fires involving electric cars, but not nearly as many as those involving gas-powered vehicles based on miles driven, according to the National Highway Traffic Safety Administration. The National Fire Protection Association reports that a driver is 5 times more likely to experience a fire in a conventional gas-powered car than in an electric car.
    Full article: "Roadshow: Electric cars not as likely to catch fire as gas-powered vehicles"

    So, Martin, thanks for raising the issue of fire safety. (And too bad you felt the need to lie about it.) That's yet another win for BEVs!
    :) :) :)
     
    Last edited: May 10, 2018
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  13. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    And an overheated cell may explode, which can spew hot electrolyte to nearby cells, contributing to a cascade event, a runaway overheating event. Li-ion battery fires are slow to start and initially slow to spread, which is why until very recently, we could report that nobody had ever been killed by a BEV car fire*. But once a lithium-ion battery pack fire really gets going, it can quite difficult to extinguish.

    *Serial Tesla FUDsters often falsely claim that bodies burned up in a handful of Tesla car crash were cases of people killed by fire. But accident investigators have concluded that (with the exception of one very recent event), such rather rare events were cases of someone being killed in a crash so severe that air bags did not save the occupant(s), and their bodies were consumed by fire after they died.

     
    Last edited: May 10, 2018
    bwilson4web likes this.
  14. Martin Williams

    Martin Williams Active Member

    Not quite. As ever, you, and whoever provided this answer, have confused 'fires' with 'fires due to crashes'. The two are not the same.

    As I pointed out any car can go on fire due to defective wiring, but usually, the occupants are able to vacate the vehicle safely. In a crash, however, they often cannot as in the case of these young men. The point is that if, in a crash, there is a high probability of the car quickly becoming an inferno, then they are FAR more dangerous to life than cars which have a tendency to spontaneously ignite at any time.

    My experience of a petrol car going on fire was limited to one experience when I and the owners watched it burn. When the fire reached the - full - gas tank, there was a significant increase in the blaze but no explosion. I think it just boiled in the tank and the resulting vapour burned. By that time the car was burning end to end.
     
  15. Martin Williams

    Martin Williams Active Member

    Very interesting Bob.

    The engineering needed to make these battery packs safe is certainly extravagant. It would appear that the cells themselves have no internal protection system and rely only on the fuse. Probably this is all you need under normal circumstances. I can't really believe that hundreds or thousands of tiny cells are the way to go though. I'd be inclined to rethink the whole approach faced with such a proposal.

    Cutting one in half was interesting, however, I think the heat and the gas were able to escape. Had he just used the blunt side of his axe and deformed it I suspect the thing might well have behaved rather more dramatically. It would have been interesting to try deforming a number of them in close proximity. A single cell getting uncomfortably hot is OK. the problem comes when you have a number of them when the heat cannot get away and the gas cannot escape. Then I think you have a big problem, especially if in a crash situation the cooling system is not working.

    I'm a bit surprised the fellow didn't use the cooling system within the battery in his boat, by the way. It would be pretty easy to dump the heat into the water with a heat exchanger which is what onboard ICEs do. My narrowboat uses a 'skin tank' to dump excess heat into the canal which is even simpler. It has a steel hull however.
     
  16. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    That is certainly true of gasmobiles. It is far less true of BEVs. If we were having this discussion a couple of weeks ago, I could have truthfully stated that nobody had ever been killed by a Tesla car fire. And so far as I know, that applies to all BEVs -- not just Tesla cars. No deaths at all due to a car fire in a BEV.

    The horrible accident which is the subject of this thread may be the first such case, if bystander reports are correct. However, as I think most of us know, bystander reports are often inaccurate or wildly wrong.

    Therefore, I'll wait until we see a report from accident investigators, rather than jumping to a conclusion based on news reports or social media reports.

     

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