15 ms·

Model S Fire

594 points by shakes 13y ago

devy 13y ago
Is Elon's claim, "the effective combustion potential is only about 1% that of the fuel in a comparable gasoline sedan", accurate? AFAIK, all the Lithium Ion Battery electrolytes are flammable (they are pressurized in the battery container too). Depending on the chemistry of the Lithium-ion battery that Model S uses, some (I.E. LFP) are safer than the others, but still, 1% potential? EVs like Chevy Volt, Fisker Karma and even Boeing 787 Dreamliner and UPS/FedEx freight flights had been caught Lithium fires in air before.
- cma 13y ago
  Wasn't there some controversy about Elon saying the Dreamliner specifically didn't have the right kind of firewalls/compartmentalization and that Tesla could help them?
  - toomuchtodo 13y ago
    Yes. http://www.reuters.com/article/2013/01/29/boeing-tesla-idUSL1N0AY11R20130129 http://www.reuters.com/article/2013/01/29/boeing-tesla-idUSL...
- Jtsummers 13y ago
  In contrast, the combustion energy of our battery pack is only about 10% of the energy contained in a gasoline tank and is divided into 16 modules with firewalls in between. As a consequence, the effective combustion potential is only about 1% that of the fuel in a comparable gasoline sedan. It seems he's dividing that 10% by 16 and rounding up based on his confidence (presented confidence or real confidence I don't know) in the firewalls.
- pja 13y ago
  In making that claim he's presumably assuming that the battery design prevents a cascading failure where the failure of one battery module causes adjacent ones to fail in turn. He's also assuming that there's no external factor that could cause all the battery compartments to fail simultaneously. It's partially PR fluff in other words. The total combustion energy of the battery pack is only 10% of that of the petrol tank in a petrol-fueled vehicle partially because the energy density of Lithium-ion cells is significantly less than petrol or diesel fuel, which is why the Model S has half the range of similar conventionally fuelled cars in it's class. I'd also speculate that he's only measuring the combustion energy of the hydrogen that could escape & ignoring any electrical heat generated. The control systems on the batteries ought to cut the connections to the cells if they detect a short of course, but no system is perfect & he's very careful to use the more specific term "combustion energy".
  - kbenson 13y ago
    > In making that claim he's presumably assuming that the battery design prevents a cascading failure where the failure of one battery module causes adjacent ones to fail in turn. He's also assuming that there's no external factor that could cause all the battery compartments to fail simultaneously. It's partially PR fluff in other words. Maybe. When the dreamliner battery fire happened, had quite a bit to say regarding batteries and cascading failure. He's surely making some assumptions (such as discounting an external factor as you state), but it's not like he isn't on record asserting they have put some effort into preventing or mitigating this exact problem[1]. [1]: http://www.dailytech.com/Tesla+CEO+Elon+Musk+Says+Boeings+787+Dreamliner+Battery+is+Unsafe/article29781.htm http://www.dailytech.com/Tesla+CEO+Elon+Musk+Says+Boeings+78...
- Someone 13y ago
  It's a 85kWh battery (http://en.wikipedia.org/wiki/Tesla_Model_S#Specifications http://en.wikipedia.org/wiki/Tesla_Model_S#Specifications). Gasoline is about 12kWh/kg or 9kWh/l (http://en.wikipedia.org/wiki/Gasoline#Energy_content http://en.wikipedia.org/wiki/Gasoline#Energy_content) So, that 85kWh battery, when driving an engine, is equivalent to about 10 liters of gasoline. I guess that's more or less what could get released in a fire (corrections welcome; I don't know what kind of factor that 'effective' could introduce) If that logic stands, to get at 1%, the typical car would have to have 1000 liters of gasoline on board (for the metric impaired: that's over 250 US gallons/over 200 imperial gallons). That, clearly, is unrealistic. Elon may have knowledge of the loading state of the battery, but if so, I think he should have mentioned that. Gasoline tanks aren't 100% full all the time, either.
  - leokun 13y ago
    > Gasoline tanks aren't 100% full all the time, either. The less gas a tank has, the more dangerous it could be. It's a common mistake to think a close to empty tank of gasoline is safer than a full one when the reverse may be true because of the fumes. For example: http://www.commerce.wa.gov.au/worksafe/content/safety_topics/hazardous_substances/Additional_resources/Empty_drums_-_potential_bombs.html http://www.commerce.wa.gov.au/worksafe/content/safety_topics...
    - sliverstorm 13y ago
      We're just talking about energy content right now, not damage potential.
    - jlgreco 13y ago
      I'm not convinced of that. If you are worried about the tank going "pop", then a mostly empty gas tank would indeed be more dangerous. However I think the more typical concern is the tank being punctured, leaking, then the leaking gas burning rather than exploding. So basically if you want it to explode hollywood style, then you need gas vapors, but if you want a very bad car fire, then you need lots of gas.
rdl 13y ago
So a truck driver who couldn't be bothered to secure his fucking load just cost Tesla shareholders $1b+?
- JumpCrisscross 13y ago
  No, jittery shareholders transferred $1b+ to their less anxious peers.
  - zeckalpha 13y ago
    And got an opportunity to double down.
- cma 13y ago
  Maybe speculative, short-term shareholders.
- ianstallings 13y ago
  I haven't seen the debris but it could have been part of the trailer itself. Not that it makes it any better. Things should not be falling off of trucks. Just saying that it might have been a maintenance issue or some kind of freak accident. That being said, If that part had punctured a gas tank of a petrol vehicle the damage could've been explosive or caused a fire also. I like how they have calculated how this happened because that most likely means in the next revision they may improve the skid plate or the battery wall to protect it from such things. Or recall them and retrofit, if needed. They aren't being mysterious like I've seen from other auto manufacturers. But then again, not every company dives in $1B in worth after a car has an accident.
  - rdl 13y ago
    I wonder if break-away would make sense.
  - maxerickson 13y ago
    In liquid form, gasoline isn't all that excited about exploding. Mythbusters did it: http://dsc.discovery.com/tv-shows/mythbusters/mythbusters-database/shooting-gas-tank.htm http://dsc.discovery.com/tv-shows/mythbusters/mythbusters-da...
Shivetya 13y ago
I really don't care about "it would be worse if it were a gasoline powered vehicle". That statement is simply trying to redirect attention. Leave statements like that out of the problem diagnoses and simply concentrate on what went right. Otherwise it looks like making excuses and that is bad.
- EStudley 13y ago
  It wouldn't have been mentioned if it wasn't already the main discussion going on about the video. News outlets love to jump on that kind of controversy, and I saw that comparison as them trying to quell the argument.
- Jtsummers 13y ago
  To some extent the comparison needed to be made based on the media reports calling into question the overall safety of EVs based on this incident. The closest equivalent for conventional vehicles is a gas fire so pointing out the (apparent) greater danger makes sense here.
- mikeash 13y ago
  Perfect safety is not attainable, and this is especially true when it comes to automobile travel, which is probably the most dangerous activity that most first-worlders engage in on a regular basis. Much of that danger is inherent to the way the system works and the current level of technology and the costs people are willing to pay. A single car maker will never be able to get anywhere remotely close to airliner levels of safety. That means that Tesla's products will be used in dangerous circumstances, and Tesla customers will die while using their product. For a normal car company, this would not be a problem, because the public accepts the current risks of automobile travel. The problem is that Tesla is Different and gets far more scrutiny. Tesla needs to convince people to accept the risks inherent in using their products. Pointing out that people accept the even greater risks inherent in using their competitors' products is a perfectly reasonable thing to do.
- tootie 13y ago
  I think it's pretty relevant. The car was in a bad accident that no car would survive. Had this been a gasoline vehicle, the damage probably would have been much worse and there would have been a higher chance of the passengers getting caught in the fire.
gkoberger 13y ago
I agree this isn't as big of a deal as the stockmarket may imply, but this line bothers me: "That equates to 1 vehicle fire for every 20 million miles driven, compared to 1 fire in over 100 million miles for Tesla. This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla!" Americans drive an aggregate of 3 trillion miles every year, while Tesla drivers have done 100 million (and they don't cite this number; are they including test drives?). That's well over an order of magnitude difference. Plus, the average Tesla driver is currently probably a superior driver (if for no other reason than they have a brand new expensive car) and has taken better care of their car (since it's within 2-3 years old, tops). In theory, Teslas will eventually become more mainstream over the years -- resold, price drops, lower-end models, etc. Again, I don't think their conclusion about Teslas being safer overall is wrong. However, their conclusion of the likelihood of a Tesla catching on fire seems off, and the exclamation mark makes this press release seem glib.
- squidi 13y ago
  > Americans drive an aggregate of 3 trillion miles, while Tesla drivers have done 100 million. That's well over an order of magnitude difference. The data on 100 million is probably enough to compare with the 3 trillion miles. The populations don't need to be equal to compare them, just big enough that they are random and distributed enough.
  - nonchalance 13y ago
    To put it in perspective, the disparity is equivalent to polling 10K americans and extrapolating to all of america (which, for better or for worse, is what most pollsters do).
    - ProCynic 13y ago
      If the sample is truly random, it doesn't matter what the population size is. Of course, truly random samples are hard to get.
      - 13y ago
EStudley 13y ago
Tesla's write-ups on their blog are the most informative reports I've seen written by a company about their own product. It's awesome to see this kind of transparency as opposed just a copy-paste statement like "Tesla is investigating the event."
- deleted 13y ago
  [deleted]
  - mbreese 13y ago
    I think that's just his tone... (at least, his blog-tone). It would have been nice to include a little, more personal, summary. Something like: In this extreme test, we feel that the car performed as designed and we are very happy that the car owner safe. Edit: the original parent said that the tone of the Tesla posts seem defensive. I'm not really sure what was wrong about the comment... they do seem a little defensive in tone. (Often understandably so...)
    - smackfu 13y ago
      Oops, I deleted the comment you were replying to, because I thought it came across a bit too negative. It essentially said that they always come across very defensive, compared to tech company post-mortems that try to be very factual.
thematrix 13y ago
This is a good explanation imo. But, the damage has been made, bad news sells, all the news outlets have just sold the bad news. Hope Tesla recovers from this faster.
smoyer 13y ago
Excellent post-mortem! And who would have thought a side-effect of disrupting the automotive industry would be training fire-fighters on the correct techniques for battling a lithium fueled fire?
deleted 13y ago
[deleted]
indus 13y ago
> "highway speed" crafty writing. read it as "high speed"
- jlgreco 13y ago
  "highway speed" is a fairly common term for the general 55-70mph range. For example, apparently the instructions to have the emissions testing system on my car become "ready" after a battery disconnect involve "at highway speed" for a half an hour or so (I learned that one last week. Fun times.)
patrickg_zill 13y ago
I think the write-up is pretty good. I would only point that 25 tons of force, isn't really a lot - I mean, the small jack that you use to lift your car can be a 5 or 6 ton device. You have a vehicle traveling a decent rate of speed, for it to strike or run over anything at all will involve tons of force. Neat explanation of the sort of math involved, with both SI and US units http://hyperphysics.phy-astr.gsu.edu/hbase/carcr.html http://hyperphysics.phy-astr.gsu.edu/hbase/carcr.html . In the example, a car going 30 mph (50km/h) striking a tree will hit with about 48 tons of force.
- jnevelson 13y ago
  In both examples that you provided, the cross-sectional area over which the force is applied is greater, so the overall pressure is lower. The magnitude of the force applied isn't the only parameter by which to judge the structural integrity in this particular instance.
- justin66 13y ago
  > I would only point that 25 tons of force, isn't really a lot - I mean, the small jack that you use to lift your car can be a 5 or 6 ton device. It's not clear to me why you'd say it's not a lot of force while making the comparison to a jack. Take a jack and use it under the wrong spot on a vehicle and you might get a pretty painful display of vehicle penetration, which is what we're really talking about here.
  - marcamillion 13y ago
    ....yet the jack produces 1/5th the amount of force. Just to put it into explicit perspective.
- timsally 13y ago
  > I would only point that 25 tons of force, isn't really a lot - I mean, the small jack that you use to lift your car can be a 5 or 6 ton device. Floor jacks easily punch through most points on modern cars. In fact, the only place that it is safe to jack up your car are special jack points which are reenforced to bear the load of the jack. The center ones on my car are pretty annoying to get to. Also, your estimate for the ratings of jacks is off by a factor of x2 to x4. Floor jacks, which have a leaver and a hydraulic component, are typically only rated for 2 to 3 tons. Scissor jacks, a manual jack that comes with your spare tire, are typically only rated at 1.5 tons or less.
hipaulshi 13y ago
wow. reading their report always inspires me to be a better engineer
lafar6502 13y ago
Wow, first serious Tesla road accident and all they can say is how unlikely it was. It was impossible before, now it's only extremely unlikely. Until next time? There are probably many other ways to destroy the battery in a collision, how likely is it to ignite when damaged?
- dangrossman 13y ago
  It was never "impossible before". Just two months ago when writing about Model S's safety rating, they stated that it was unlikely to remain the case forever that a Tesla car has never caught fire or caused an occupant fatality. They've always published First Responder fact sheets for their cars which talk about how firefighters should handle a battery on fire. http://www.teslamotors.com/sites/default/files/downloads/20130214_ModelS_Emergency_Response_Guide.pdf http://www.teslamotors.com/sites/default/files/downloads/201...
- SeanLuke 13y ago
  There have been many more serious road accidents with Teslas. Just ones with more mundane causes.
RyJones 13y ago
I wonder what he means by 1/4" armor plate - AR500? Is it actually rated for armor plating, or just built with material from which you could also build rated plates?
001sky 13y ago
Initial attempts to douse the fire were unsuccessful. “The fire appeared to be extinguished, then reignited underneath the vehicle,” the report said. Firefighters had to use a jack to turn the Model S on its side, and then cut a hole in the car to apply water to the burning battery. He seemed to skip that last bit. (?)
- baddox 13y ago
  I have seen videos of normal gasoline car fires that behave the same way.
  - 001sky 13y ago
    What did they use to cut the hole in the gas tank with? Just curious.
codex 13y ago
It looks like they're backing off the claim that the fire was contained to only one cell. It's unclear, but if the fire were contained to only one cell, it's likely they would mention it: "A fire caused by the impact began in the front battery module – the battery pack has a total of 16 modules – but was contained to the front section of the car by internal firewalls within the pack." If the fire was able to jump cells, does this make the battery pack "fundamentally unsound", as Elon has described the Boeing battery? Not necessarily. However, merely puncturing the gas tank of a ICE car in this way is not guaranteed to set the gasoline on fire. The ignition temperature of gasoline is over 500 F and the gas tank itself is plastic, most likely. Gasoline vapor is explosive, but the car was traveling fairly rapidly and a there's a fair amount of wind to dispel vapor. The ignition source would have to be heat from the metal of the debris self-striking metal of the debris, or though both layers of plastic to the auto frame itself, and that spark would have to find some gasoline, which is pooled at the bottom of the tank and not near the top. I suppose it's possible. Car crashes do produce burning gasoline, though usually it's a very severe crash that mixes gas vapor with the heat of the engine.
- btbuilder 13y ago
  I also wonder whether the surface area that, if punctured, poses a fire risk is larger on a Tesla than on a gasoline vehicle.
- 001sky 13y ago
  within the pac This is worth noting. The fire did not stop and kept reignighting. The FD had to flip the car on its side and physically gain access by cutting the car up, to put the fire out. Under this scenario, it seems dubious that compartmentalization would be sufficient. Thermal conductivity at some stage would overcome the situation. Also, you are right to highlight that petrol fuel systems are a cause only on a tiny minority of real-life auto accident related fires (~2%). The safety of petrol engines is actually quite high in this regards (counter-intuitive, perhaps). Plastic has the ability to deform rather than crack (flexibil vs brittle) and also the position of the fuel cells is much more protected. Think about the debris from front-tires -- much more likely to hit the undercarriage (where the Tesla battery is) than behind the rear axel (where many tanks are). Debris hit by the rear tires of course exits behidnd the car in either scenario. This setup is obviously not by chance. The Li Ion battery is probably low for COG reasons and fore-aft weight distribution. Li ION is much heavier than petrol.
ebiester 13y ago
Two things. 1. I have had my gasoline car catch on fire in my lifetime. (That was the end of the car.) However, it was having a lot of trouble at the time and we had just taken it to the mechanic. (That's right, it caught on fire at the mechanic's shop. We were still waiting to talk to the mechanic before going back home when it caught on fire.) This was not the only on-fire incident among our friends. One had his minivan catch on fire in a gas station. But both of them were old cars. What is to say that most of the cars that catch on fire aren't much older than the Tesla? What is to say that the Tesla won't have more trouble as it gets older? Oh yeah. The batteries will have to be replaced before the car is run down as much as our old beaters were. And Tesla owners will have the money to maintain their cars better than we did as teenagers. So, what I'm saying is that the real test will be in a decade. More fires will probably happen, just like regular cars do. Either way, it's probably not dangerous enough to be worth avoiding buying a new one.
- reportingsjr 13y ago
  Curious as to your reasoning on saying that the batteries will have to be replaced before the car is as run down as your old cars. So far evidence is pointing towards batteries lasting much longer than originally thought. How old were your cars?
  - hayksaakian 13y ago
    They still HAVE to be replace whereas a 30 year old car can continue to run a Teenagers budget
  - ebiester 13y ago
    We're talking about 15-20 year old cars.
abalone 13y ago
Question: Is it really that unusual to have 25 tons of force applied to a point of the underside of the car in an accident? Does anyone know? My conjecture: The Model S is a heavy car. Hit something pokey at speed and you've got an awful lot of forces channeled to a point. I also thought it a bit much that Musk tried to compare this to severing "fuel supply lines" in a gas car. The likelihood of a 3 inch puncture severing a fuel line or entering the gas tank is vastly lower than compromising a battery pack that runs the length of the underside of the car. The Tesla's underbelly vulnerability zone is vastly larger than fuel tanks and lines.. and a punctured battery doesn't need an ignition source to start a fire, either.
- chroem 13y ago
  Looking At some pictures and diagrams of the Model S battery pack, yes, it does look to be about twice as large as the average fuel tank. HOWEVER, that leaves out some really interesting things to note. First of all, most automotive gas tanks are made out of ~1/8" HDPE. While it has decent cut and abrasion resistance, it's of virtually no use when trying to combat punctures and is also pretty flimsy, leading to deformation and possible cracking during an accident. While, yes, a punctured battery pack is guaranteed to ignite while a gas tank is not, that is also the only way for the pack to ignite. An object has to physically pass through the battery pack, while a gas tank could potentially start a fire if it cracks and starts leaking. There's a reason why you're supposed to try to get out your car as quickly as possible in case of a crash: fuel leaks very easily. In comparison, batteries are much more impact resistant due to their more solid state nature. Also, it seems that whatever struck the car seemed to hit under or very close to where the front passengers sit. Had that armored battery pack not been there, there's a very real possibility that the driver would have been impaled. With that in mind, it should be pretty clear that this was a freak accident and not really representative of the average car crash.
robomartin 13y ago
> This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla! I LOVE THE COMPANY. I DON'T ENJOY OR APPRECIATE THE LAME MARKETING ATTEMPTS THEY SOMETIMES MAKE. Just like that whole business of jumping through hoops to make it seem like there was some new magical way to finance a Tesla, this is wrong. Trying to create a safety metric by comparing the number of fires to the number of miles driven per vehicle type is pure nonsense. You have to look at the causes and mechanisms of the fires and dig a lot deeper than that in order to even hope to generate a meaningful metric. Here's an imperfect analogy (numbers made-up): One million people run marathons every year world wide. 1000 have heart attacks and die. Ten thousand people have run marathons with our shoes and only one had a heart attack and didn't die. You are far less likely to have a heart attack and die if you run marathons with our shoes. Nonsense. Right? RIGHT. Almost anyone would look at that and recognize it as a poor attempt to create a nexus where one does not exist. I think it's bad marketing. Now, if we started to dive into the statistics and identified location, weather conditions, age, physical conditioning, pre-existing conditions (heart problem they did not know about), etc. we might actually be able to attempt a comparison between people wearing the new shoes vs. the other brands. Even then, the nexus would be tenuous at best. A similar exercise would be needed to compare car fires between brands and types with any degree of validity. I don't have the time to dive into the stats. It was easy enough to Google [0][1][2][3] and do a quick scan: It is easy to see that young males are more likely to be involved in a car fire. There are statistics about different brands having different fatality rates (not necessarily related). Lots of fires are caused by running equipment. Lots of fires originate in the engine compartment. Mechanical and electrical failures seem to account for over 60% of fires. The point is simple: Far more extensive and detailed statistical work needs to be undertaken before anyone can conclude absolutely anything on the merits of any particular car or design as it pertains to potential to cause fires. Elon and his team are very smart. They know this. And this is why some of their marketing of late feels really dirty and beneath them. This is Tesla reacting to news that affected their stock price and, potentially, buyer sentiment, with marketing rather than the truth. Are Tesla's safer than all gasoline cars? That question is probably not an easy one to answer at all. There's the potential for a theoretical sort of an answer based on design. For example, there are no fuel lines to rupture. Does that mean it is safer? Hard to say. What do you compare that to? Perhaps you can list all the potential sources of ignition and sort them by probability and MTBF? Not sure. Of course, then you have the real-life probability. Once you get a million cars on the road with all kinds of people, driving in all conditions, roads and levels of maintenance and neglect things can change dramatically. If I remember correctly Tesla has somewhere in the order of twenty thousand. There's a reason we see major car companies recall hundreds of thousands of cars every so often. Shit happens. Design error are made. And it can take time and a massive installed base to discover them. THE TRUTH OF THE MATTER is these are the kinds of tests electric cars will have to endure over a period of time in order to reach wide adoption. Despite what's been said here a full tank of gasoline is far safer than a fully charged battery pack with enough energy to go 300 miles. Before anyone mauls me, consider how many gasoline cars have been driven and, yes, crashed, world-wide since gasoline cars came into mass production. Not last year. Since forever. There have probably been millions of accidents without fires, even with fuel leaks. There's probably no imaginable way to compare the two at this time. We simply don't have enough data. And, no, linking to a horrible crash video on youtube involving gasoline igniting does absolutley nothing to support arguments on either side. The one issue with electrics that is not spoken of is the fact that you have a several hundred volt high energy system that could very well electrocute passengers. I fully expect that to happen one day (in general, not necessarily Tesla). If and when that happens you can bet it will set the breaks on electrics for a while and relevant stocks will plummet. I still believe electric cars are the future. We simply need to go though the evolutionary process that will make them really safe for hundreds of millions of electrics to share the road. What happens when you have a pile-up of ten or twenty electric cars on a fogg-covered highway? A pile of mangled wrecks with 400 Volt high energy systems is unimaginably dangerous. I can think of a few horrific scenarios under those conditions. At some level part of me thinks that fuel cells are the future, not batteries. Having something relatively benign that can leak out would be a good thing. A few months ago there was a horrific crash in my neighborhood. This 18 year old kid decided it was OK to go 100 miles per hour on this avenue. He lost control and plowed into a bunch of cars parked by the side of the road. He absolutely destroyed seven of them before coming to a stop. Most of the cars were mangled beyond recognition. He was driving an SUV with a lot of mass. His SUV was nearly cut in half and impaled into one of the cars to a degree that made it difficult to see where one car started and the other ended. Almost like taking two lumps of play-doh and mixing them together. No fire. Gasoline all over the place but no ignition at all. He hit the first car, fused into it and the "ball" formed by the two cars proceeded to destroy the other six. Absolutely amazing display of how much kinetic energy was dissipated. Had this been eight fully-charged electric cars I am almost certain there would have been a horrific fire as well as the potential for absolutely impossible to describe electrocution of some of the passengers. And, to make matters worst, it would have taken the rescue crew far longer to remove the victims as they would have to be worries about electrocuting themselves and the victims (at the very least). Until there are enough electric cars on the road to have a massive pile-up accident [4] where most cars are electric we will not really understand the practical reality of a world where every car on the road is electric. Imagine having to walk out of a one hundred mangled car pile-up where every car has a battery pack storing enough energy to drive 300 to 400 miles and they are wired to produce hundreds of volts. I can't imagine anyone who understands electronics and electricity that would tell me all would be well after looking at the pictures from this accident [4] if all cars were electric. Look at pictures 1, 8 and 11. No fires. Gasoline isn't all that bad in this regard. [0] http://www.usfa.fema.gov/downloads/pdf/statistics/v13i11.pdf http://www.usfa.fema.gov/downloads/pdf/statistics/v13i11.pdf [1] http://www.usfa.fema.gov/statistics/reports/vehicles.shtm http://www.usfa.fema.gov/statistics/reports/vehicles.shtm [2] http://www.chandlerlawgroup.com/library/national-vehicle-fire-statistics.cfm http://www.chandlerlawgroup.com/library/national-vehicle-fir... [3] http://www.statisticbrain.com/driver-fatality-stats-by-auto-make/ http://www.statisticbrain.com/driver-fatality-stats-by-auto-... [4] http://www.cnn.com/2013/09/05/world/europe/uk-huge-chain-reaction-crash/index.html http://www.cnn.com/2013/09/05/world/europe/uk-huge-chain-rea...
sgustard 13y ago
If Toyota owners got one of these emails every time one of them caught on fire it would be sort of a downer, so I guess you only have a few chances to make it a PR event.
uladzislau 13y ago
The title is missing word "incident". My first thought was that Tesla has a new model "S Fire".
- kintamanimatt 13y ago
  A car called Model S Fire would be like a software package called Microsoft Crash.
mixmax 13y ago
My boat's hull happens to be made of 1/4 inch metal plate (6mm) which is apparently the same as the protected underside of a Tesla. I've hit a concrete block, gone aground a few times and generally have a bit of excperiencing with impacting hard immovable objects with a vehicle protected by a 1/4 inch metal plate. It takes a LOT of force to pierce 1/4 inch plate. My boat weighs 12 tons, and it hardly has a dent from the collissions I and previous owners have been in.
- nubela 13y ago
  your point being?
  - mixmax 13y ago
    that if a tesla has a 1/4 inch protective plate seperating the batteries from the road it's a safe vehicle indeed. I was simply sharing my personal experience with ramming 1/4 inch plated vehicles into hard immovable objects to give some perspective as to what kind of strength we're talking about.
  - GeneralMayhem 13y ago
    The fire in question involved the piercing of a 1/4" plate protecting the battery from below. If that's a thick enough plate to protect a 12-ton boat, which has more momentum than the Tesla even at much slower speeds, with hardly a dent, then the Tesla incident was very, very out of the ordinary.
anoother 13y ago
As much as I admire the work Tesla and Elon Musk are doing, I can't help but feel that the press releases issued by the company are at times overly defensive. We all know there is negative rhetoric bouncing around about this incident. It seems to me that, precisely because of this, there really isn't a need to write in such a manner—trying to block all possible avenues of attack as if one is a afraid of what will be written in response. The tone, to me, betrays insecurity, and this seems something at odds with the bullish, innovative nature of the non-PR aspects of the business.
senthilnayagam 13y ago
Stakes are high, for sure Elon Musk & Tesla would review its design, would possibly add protection for these type of accidents. Will any other gasoline car manufacturer be willing to participate in such crash test what model S encountered, I doubt anyone will.
tn13 13y ago
The following statement is wrong at many levels. "That equates to 1 vehicle fire for every 20 million miles driven, compared to 1 fire in over 100 million miles for Tesla. This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla!" - All Tesla cars are new and almost all of them have superior drivers. - They drive their cars only on certain roads where as Gasoline cars are almost everywhere. - You can not compare 100m sample set with 2 trillion size sample set.
- zalew 13y ago
  And he forgot to mention many gasoline car fires aren't due to gasoline ignition, but electrical failures or material melting (plastic/glue), etc. The only common case of gas ignition is static electricity while filling up, f.ex. re-entering the car while wearing a sweater (you can even smoke a cigarette while filling up, it's the spark that's dangerous). Closed gasoline tanks have been safe for decades and contrary to what we see in movies it's close to impossible to fire them up even in serious car crashes, especially when they're full. There is even a method for extreme freezes (-30-40'c) to light a small fire under the tank to help the fuel flow to start the engine (especially needed for diesels and low quality gasoline) and the only fires due to that are when the stupid owner didn't realize his tank or other parts around are plastic (which's quite a modern day problem).
bsullivan01 13y ago
Fire happens. Maybe Tesla performs better, maybe not but cars do catch fire. I, however, will not be buying Elon's explanations simply because he seems like a cheesy salesman and a media whore. http://www.bloomberg.com/news/2013-04-02/tesla-to-begin-model-s-financing-with-u-s-bancorp-wells-fargo.html http://www.bloomberg.com/news/2013-04-02/tesla-to-begin-mode... (Knowing the Elon is the Sun God among many here, I want to say this: I do not particularly care about karma, I'm saying 100% of what I am thinking.)
nodesocket 13y ago
I wrote a blog post on this last night (Tesla model S and the three laws of robotics). http://justink.svbtle.com/tesla-model-s-and-the-three-laws-of-robotics http://justink.svbtle.com/tesla-model-s-and-the-three-laws-o...
001sky 13y ago
A little closer reading of the report[1,2], shows that only 26,000 automobile fires occur on public highways. That makes Tesla's single datapoint worse than a conventional Auto. All cars: 1 fire per 116 million vehicle miles/year Tesla: 1 fire per 113 m vehicle miles/since inception Obviously, the Model (s) being a newer Tesla model does not have the full historical amount of "Tesla" Miles as the denominator. [1] http://www.nfpa.org/~/media/files/research/nfpa%20reports/vehicles/osautomobilefires.pdf http://www.nfpa.org/~/media/files/research/nfpa%20reports/ve... [2] Furthermore, only 2% of non-deliberate fires start in the fuel line or fuel tank of a normal vehicle
zw123456 13y ago
Tesla, recall is coming, that is obvious. You will be forced to put in stronger armor underneath. So drop the price by $10K, or do the recall sooner. Either way that is the reason for the stock hit, people know one or the other or both are coming.
Kiro 13y ago
Why are people on HN so keen on defending Tesla at all cost?
hkmurakami 13y ago
Totally thought this was a name for a new model S model, a la kindle fire.
fus 13y ago
"Had a conventional gasoline car encountered the same object on the highway, the result could have been far worse." Diesel-powered car would be much safer, since oil requires something like a wick in it to burn. It's hard to argue with Tesla's statement, since argument is true; but it doesn't include this issue in electric vs ICE vehicle competition.
jmount 13y ago
I've blogged a fun writeup of the math in the (unimportant and actually against Tesla) formal bias in evaluating a failure rate right after the first failure: http://www.win-vector.com/blog/2013/10/estimating-rates-from-a-single-occurrence-of-a-rare-event/ http://www.win-vector.com/blog/2013/10/estimating-rates-from...
oddshocks 13y ago
He is just great
- oddshocks 13y ago
  Downvote me for my opinion you HN haters bring it on

594 points by shakes 13y ago

devy 13y ago

Is Elon's claim, "the effective combustion potential is only about 1% that of the fuel in a comparable gasoline sedan", accurate? AFAIK, all the Lithium Ion Battery electrolytes are flammable (they are pressurized in the battery container too). Depending on the chemistry of the Lithium-ion battery that Model S uses, some (I.E. LFP) are safer than the others, but still, 1% potential? EVs like Chevy Volt, Fisker Karma and even Boeing 787 Dreamliner and UPS/FedEx freight flights had been caught Lithium fires in air before.

cma 13y ago
Wasn't there some controversy about Elon saying the Dreamliner specifically didn't have the right kind of firewalls/compartmentalization and that Tesla could help them?
- toomuchtodo 13y ago
  Yes. http://www.reuters.com/article/2013/01/29/boeing-tesla-idUSL1N0AY11R20130129 http://www.reuters.com/article/2013/01/29/boeing-tesla-idUSL...
Jtsummers 13y ago
In contrast, the combustion energy of our battery pack is only about 10% of the energy contained in a gasoline tank and is divided into 16 modules with firewalls in between. As a consequence, the effective combustion potential is only about 1% that of the fuel in a comparable gasoline sedan. It seems he's dividing that 10% by 16 and rounding up based on his confidence (presented confidence or real confidence I don't know) in the firewalls.
pja 13y ago
In making that claim he's presumably assuming that the battery design prevents a cascading failure where the failure of one battery module causes adjacent ones to fail in turn. He's also assuming that there's no external factor that could cause all the battery compartments to fail simultaneously. It's partially PR fluff in other words. The total combustion energy of the battery pack is only 10% of that of the petrol tank in a petrol-fueled vehicle partially because the energy density of Lithium-ion cells is significantly less than petrol or diesel fuel, which is why the Model S has half the range of similar conventionally fuelled cars in it's class. I'd also speculate that he's only measuring the combustion energy of the hydrogen that could escape & ignoring any electrical heat generated. The control systems on the batteries ought to cut the connections to the cells if they detect a short of course, but no system is perfect & he's very careful to use the more specific term "combustion energy".
- kbenson 13y ago
  > In making that claim he's presumably assuming that the battery design prevents a cascading failure where the failure of one battery module causes adjacent ones to fail in turn. He's also assuming that there's no external factor that could cause all the battery compartments to fail simultaneously. It's partially PR fluff in other words. Maybe. When the dreamliner battery fire happened, had quite a bit to say regarding batteries and cascading failure. He's surely making some assumptions (such as discounting an external factor as you state), but it's not like he isn't on record asserting they have put some effort into preventing or mitigating this exact problem[1]. [1]: http://www.dailytech.com/Tesla+CEO+Elon+Musk+Says+Boeings+787+Dreamliner+Battery+is+Unsafe/article29781.htm http://www.dailytech.com/Tesla+CEO+Elon+Musk+Says+Boeings+78...
Someone 13y ago
It's a 85kWh battery (http://en.wikipedia.org/wiki/Tesla_Model_S#Specifications http://en.wikipedia.org/wiki/Tesla_Model_S#Specifications). Gasoline is about 12kWh/kg or 9kWh/l (http://en.wikipedia.org/wiki/Gasoline#Energy_content http://en.wikipedia.org/wiki/Gasoline#Energy_content) So, that 85kWh battery, when driving an engine, is equivalent to about 10 liters of gasoline. I guess that's more or less what could get released in a fire (corrections welcome; I don't know what kind of factor that 'effective' could introduce) If that logic stands, to get at 1%, the typical car would have to have 1000 liters of gasoline on board (for the metric impaired: that's over 250 US gallons/over 200 imperial gallons). That, clearly, is unrealistic. Elon may have knowledge of the loading state of the battery, but if so, I think he should have mentioned that. Gasoline tanks aren't 100% full all the time, either.
- leokun 13y ago
  > Gasoline tanks aren't 100% full all the time, either. The less gas a tank has, the more dangerous it could be. It's a common mistake to think a close to empty tank of gasoline is safer than a full one when the reverse may be true because of the fumes. For example: http://www.commerce.wa.gov.au/worksafe/content/safety_topics/hazardous_substances/Additional_resources/Empty_drums_-_potential_bombs.html http://www.commerce.wa.gov.au/worksafe/content/safety_topics...
  - sliverstorm 13y ago
    We're just talking about energy content right now, not damage potential.
  - jlgreco 13y ago
    I'm not convinced of that. If you are worried about the tank going "pop", then a mostly empty gas tank would indeed be more dangerous. However I think the more typical concern is the tank being punctured, leaking, then the leaking gas burning rather than exploding. So basically if you want it to explode hollywood style, then you need gas vapors, but if you want a very bad car fire, then you need lots of gas.

rdl 13y ago

So a truck driver who couldn't be bothered to secure his fucking load just cost Tesla shareholders $1b+?

JumpCrisscross 13y ago
No, jittery shareholders transferred $1b+ to their less anxious peers.
- zeckalpha 13y ago
  And got an opportunity to double down.
cma 13y ago
Maybe speculative, short-term shareholders.
ianstallings 13y ago
I haven't seen the debris but it could have been part of the trailer itself. Not that it makes it any better. Things should not be falling off of trucks. Just saying that it might have been a maintenance issue or some kind of freak accident. That being said, If that part had punctured a gas tank of a petrol vehicle the damage could've been explosive or caused a fire also. I like how they have calculated how this happened because that most likely means in the next revision they may improve the skid plate or the battery wall to protect it from such things. Or recall them and retrofit, if needed. They aren't being mysterious like I've seen from other auto manufacturers. But then again, not every company dives in $1B in worth after a car has an accident.
- rdl 13y ago
  I wonder if break-away would make sense.
- maxerickson 13y ago
  In liquid form, gasoline isn't all that excited about exploding. Mythbusters did it: http://dsc.discovery.com/tv-shows/mythbusters/mythbusters-database/shooting-gas-tank.htm http://dsc.discovery.com/tv-shows/mythbusters/mythbusters-da...

Shivetya 13y ago

I really don't care about "it would be worse if it were a gasoline powered vehicle". That statement is simply trying to redirect attention. Leave statements like that out of the problem diagnoses and simply concentrate on what went right. Otherwise it looks like making excuses and that is bad.

EStudley 13y ago
It wouldn't have been mentioned if it wasn't already the main discussion going on about the video. News outlets love to jump on that kind of controversy, and I saw that comparison as them trying to quell the argument.
Jtsummers 13y ago
To some extent the comparison needed to be made based on the media reports calling into question the overall safety of EVs based on this incident. The closest equivalent for conventional vehicles is a gas fire so pointing out the (apparent) greater danger makes sense here.
mikeash 13y ago
Perfect safety is not attainable, and this is especially true when it comes to automobile travel, which is probably the most dangerous activity that most first-worlders engage in on a regular basis. Much of that danger is inherent to the way the system works and the current level of technology and the costs people are willing to pay. A single car maker will never be able to get anywhere remotely close to airliner levels of safety. That means that Tesla's products will be used in dangerous circumstances, and Tesla customers will die while using their product. For a normal car company, this would not be a problem, because the public accepts the current risks of automobile travel. The problem is that Tesla is Different and gets far more scrutiny. Tesla needs to convince people to accept the risks inherent in using their products. Pointing out that people accept the even greater risks inherent in using their competitors' products is a perfectly reasonable thing to do.
tootie 13y ago
I think it's pretty relevant. The car was in a bad accident that no car would survive. Had this been a gasoline vehicle, the damage probably would have been much worse and there would have been a higher chance of the passengers getting caught in the fire.

gkoberger 13y ago

I agree this isn't as big of a deal as the stockmarket may imply, but this line bothers me: "That equates to 1 vehicle fire for every 20 million miles driven, compared to 1 fire in over 100 million miles for Tesla. This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla!" Americans drive an aggregate of 3 trillion miles every year, while Tesla drivers have done 100 million (and they don't cite this number; are they including test drives?). That's well over an order of magnitude difference. Plus, the average Tesla driver is currently probably a superior driver (if for no other reason than they have a brand new expensive car) and has taken better care of their car (since it's within 2-3 years old, tops). In theory, Teslas will eventually become more mainstream over the years -- resold, price drops, lower-end models, etc. Again, I don't think their conclusion about Teslas being safer overall is wrong. However, their conclusion of the likelihood of a Tesla catching on fire seems off, and the exclamation mark makes this press release seem glib.

squidi 13y ago
> Americans drive an aggregate of 3 trillion miles, while Tesla drivers have done 100 million. That's well over an order of magnitude difference. The data on 100 million is probably enough to compare with the 3 trillion miles. The populations don't need to be equal to compare them, just big enough that they are random and distributed enough.
- nonchalance 13y ago
  To put it in perspective, the disparity is equivalent to polling 10K americans and extrapolating to all of america (which, for better or for worse, is what most pollsters do).
  - ProCynic 13y ago
    If the sample is truly random, it doesn't matter what the population size is. Of course, truly random samples are hard to get.
    - 13y ago

EStudley 13y ago

Tesla's write-ups on their blog are the most informative reports I've seen written by a company about their own product. It's awesome to see this kind of transparency as opposed just a copy-paste statement like "Tesla is investigating the event."

deleted 13y ago
[deleted]
- mbreese 13y ago
  I think that's just his tone... (at least, his blog-tone). It would have been nice to include a little, more personal, summary. Something like: In this extreme test, we feel that the car performed as designed and we are very happy that the car owner safe. Edit: the original parent said that the tone of the Tesla posts seem defensive. I'm not really sure what was wrong about the comment... they do seem a little defensive in tone. (Often understandably so...)
  - smackfu 13y ago
    Oops, I deleted the comment you were replying to, because I thought it came across a bit too negative. It essentially said that they always come across very defensive, compared to tech company post-mortems that try to be very factual.

thematrix 13y ago

This is a good explanation imo. But, the damage has been made, bad news sells, all the news outlets have just sold the bad news. Hope Tesla recovers from this faster.

smoyer 13y ago

Excellent post-mortem! And who would have thought a side-effect of disrupting the automotive industry would be training fire-fighters on the correct techniques for battling a lithium fueled fire?

deleted 13y ago

[deleted]

indus 13y ago

> "highway speed" crafty writing. read it as "high speed"

jlgreco 13y ago
"highway speed" is a fairly common term for the general 55-70mph range. For example, apparently the instructions to have the emissions testing system on my car become "ready" after a battery disconnect involve "at highway speed" for a half an hour or so (I learned that one last week. Fun times.)

patrickg_zill 13y ago

I think the write-up is pretty good. I would only point that 25 tons of force, isn't really a lot - I mean, the small jack that you use to lift your car can be a 5 or 6 ton device. You have a vehicle traveling a decent rate of speed, for it to strike or run over anything at all will involve tons of force. Neat explanation of the sort of math involved, with both SI and US units http://hyperphysics.phy-astr.gsu.edu/hbase/carcr.html http://hyperphysics.phy-astr.gsu.edu/hbase/carcr.html . In the example, a car going 30 mph (50km/h) striking a tree will hit with about 48 tons of force.

jnevelson 13y ago
In both examples that you provided, the cross-sectional area over which the force is applied is greater, so the overall pressure is lower. The magnitude of the force applied isn't the only parameter by which to judge the structural integrity in this particular instance.
justin66 13y ago
> I would only point that 25 tons of force, isn't really a lot - I mean, the small jack that you use to lift your car can be a 5 or 6 ton device. It's not clear to me why you'd say it's not a lot of force while making the comparison to a jack. Take a jack and use it under the wrong spot on a vehicle and you might get a pretty painful display of vehicle penetration, which is what we're really talking about here.
- marcamillion 13y ago
  ....yet the jack produces 1/5th the amount of force. Just to put it into explicit perspective.
timsally 13y ago
> I would only point that 25 tons of force, isn't really a lot - I mean, the small jack that you use to lift your car can be a 5 or 6 ton device. Floor jacks easily punch through most points on modern cars. In fact, the only place that it is safe to jack up your car are special jack points which are reenforced to bear the load of the jack. The center ones on my car are pretty annoying to get to. Also, your estimate for the ratings of jacks is off by a factor of x2 to x4. Floor jacks, which have a leaver and a hydraulic component, are typically only rated for 2 to 3 tons. Scissor jacks, a manual jack that comes with your spare tire, are typically only rated at 1.5 tons or less.

hipaulshi 13y ago

wow. reading their report always inspires me to be a better engineer

lafar6502 13y ago

Wow, first serious Tesla road accident and all they can say is how unlikely it was. It was impossible before, now it's only extremely unlikely. Until next time? There are probably many other ways to destroy the battery in a collision, how likely is it to ignite when damaged?

dangrossman 13y ago
It was never "impossible before". Just two months ago when writing about Model S's safety rating, they stated that it was unlikely to remain the case forever that a Tesla car has never caught fire or caused an occupant fatality. They've always published First Responder fact sheets for their cars which talk about how firefighters should handle a battery on fire. http://www.teslamotors.com/sites/default/files/downloads/20130214_ModelS_Emergency_Response_Guide.pdf http://www.teslamotors.com/sites/default/files/downloads/201...
SeanLuke 13y ago
There have been many more serious road accidents with Teslas. Just ones with more mundane causes.

RyJones 13y ago

I wonder what he means by 1/4" armor plate - AR500? Is it actually rated for armor plating, or just built with material from which you could also build rated plates?

001sky 13y ago

Initial attempts to douse the fire were unsuccessful. “The fire appeared to be extinguished, then reignited underneath the vehicle,” the report said. Firefighters had to use a jack to turn the Model S on its side, and then cut a hole in the car to apply water to the burning battery. He seemed to skip that last bit. (?)

baddox 13y ago
I have seen videos of normal gasoline car fires that behave the same way.
- 001sky 13y ago
  What did they use to cut the hole in the gas tank with? Just curious.

codex 13y ago

It looks like they're backing off the claim that the fire was contained to only one cell. It's unclear, but if the fire were contained to only one cell, it's likely they would mention it: "A fire caused by the impact began in the front battery module – the battery pack has a total of 16 modules – but was contained to the front section of the car by internal firewalls within the pack." If the fire was able to jump cells, does this make the battery pack "fundamentally unsound", as Elon has described the Boeing battery? Not necessarily. However, merely puncturing the gas tank of a ICE car in this way is not guaranteed to set the gasoline on fire. The ignition temperature of gasoline is over 500 F and the gas tank itself is plastic, most likely. Gasoline vapor is explosive, but the car was traveling fairly rapidly and a there's a fair amount of wind to dispel vapor. The ignition source would have to be heat from the metal of the debris self-striking metal of the debris, or though both layers of plastic to the auto frame itself, and that spark would have to find some gasoline, which is pooled at the bottom of the tank and not near the top. I suppose it's possible. Car crashes do produce burning gasoline, though usually it's a very severe crash that mixes gas vapor with the heat of the engine.

btbuilder 13y ago
I also wonder whether the surface area that, if punctured, poses a fire risk is larger on a Tesla than on a gasoline vehicle.
001sky 13y ago
within the pac This is worth noting. The fire did not stop and kept reignighting. The FD had to flip the car on its side and physically gain access by cutting the car up, to put the fire out. Under this scenario, it seems dubious that compartmentalization would be sufficient. Thermal conductivity at some stage would overcome the situation. Also, you are right to highlight that petrol fuel systems are a cause only on a tiny minority of real-life auto accident related fires (~2%). The safety of petrol engines is actually quite high in this regards (counter-intuitive, perhaps). Plastic has the ability to deform rather than crack (flexibil vs brittle) and also the position of the fuel cells is much more protected. Think about the debris from front-tires -- much more likely to hit the undercarriage (where the Tesla battery is) than behind the rear axel (where many tanks are). Debris hit by the rear tires of course exits behidnd the car in either scenario. This setup is obviously not by chance. The Li Ion battery is probably low for COG reasons and fore-aft weight distribution. Li ION is much heavier than petrol.

ebiester 13y ago

Two things. 1. I have had my gasoline car catch on fire in my lifetime. (That was the end of the car.) However, it was having a lot of trouble at the time and we had just taken it to the mechanic. (That's right, it caught on fire at the mechanic's shop. We were still waiting to talk to the mechanic before going back home when it caught on fire.) This was not the only on-fire incident among our friends. One had his minivan catch on fire in a gas station. But both of them were old cars. What is to say that most of the cars that catch on fire aren't much older than the Tesla? What is to say that the Tesla won't have more trouble as it gets older? Oh yeah. The batteries will have to be replaced before the car is run down as much as our old beaters were. And Tesla owners will have the money to maintain their cars better than we did as teenagers. So, what I'm saying is that the real test will be in a decade. More fires will probably happen, just like regular cars do. Either way, it's probably not dangerous enough to be worth avoiding buying a new one.

reportingsjr 13y ago
Curious as to your reasoning on saying that the batteries will have to be replaced before the car is as run down as your old cars. So far evidence is pointing towards batteries lasting much longer than originally thought. How old were your cars?
- hayksaakian 13y ago
  They still HAVE to be replace whereas a 30 year old car can continue to run a Teenagers budget
- ebiester 13y ago
  We're talking about 15-20 year old cars.

abalone 13y ago

Question: Is it really that unusual to have 25 tons of force applied to a point of the underside of the car in an accident? Does anyone know? My conjecture: The Model S is a heavy car. Hit something pokey at speed and you've got an awful lot of forces channeled to a point. I also thought it a bit much that Musk tried to compare this to severing "fuel supply lines" in a gas car. The likelihood of a 3 inch puncture severing a fuel line or entering the gas tank is vastly lower than compromising a battery pack that runs the length of the underside of the car. The Tesla's underbelly vulnerability zone is vastly larger than fuel tanks and lines.. and a punctured battery doesn't need an ignition source to start a fire, either.

chroem 13y ago
Looking At some pictures and diagrams of the Model S battery pack, yes, it does look to be about twice as large as the average fuel tank. HOWEVER, that leaves out some really interesting things to note. First of all, most automotive gas tanks are made out of ~1/8" HDPE. While it has decent cut and abrasion resistance, it's of virtually no use when trying to combat punctures and is also pretty flimsy, leading to deformation and possible cracking during an accident. While, yes, a punctured battery pack is guaranteed to ignite while a gas tank is not, that is also the only way for the pack to ignite. An object has to physically pass through the battery pack, while a gas tank could potentially start a fire if it cracks and starts leaking. There's a reason why you're supposed to try to get out your car as quickly as possible in case of a crash: fuel leaks very easily. In comparison, batteries are much more impact resistant due to their more solid state nature. Also, it seems that whatever struck the car seemed to hit under or very close to where the front passengers sit. Had that armored battery pack not been there, there's a very real possibility that the driver would have been impaled. With that in mind, it should be pretty clear that this was a freak accident and not really representative of the average car crash.

robomartin 13y ago

> This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla! I LOVE THE COMPANY. I DON'T ENJOY OR APPRECIATE THE LAME MARKETING ATTEMPTS THEY SOMETIMES MAKE. Just like that whole business of jumping through hoops to make it seem like there was some new magical way to finance a Tesla, this is wrong. Trying to create a safety metric by comparing the number of fires to the number of miles driven per vehicle type is pure nonsense. You have to look at the causes and mechanisms of the fires and dig a lot deeper than that in order to even hope to generate a meaningful metric. Here's an imperfect analogy (numbers made-up): One million people run marathons every year world wide. 1000 have heart attacks and die. Ten thousand people have run marathons with our shoes and only one had a heart attack and didn't die. You are far less likely to have a heart attack and die if you run marathons with our shoes. Nonsense. Right? RIGHT. Almost anyone would look at that and recognize it as a poor attempt to create a nexus where one does not exist. I think it's bad marketing. Now, if we started to dive into the statistics and identified location, weather conditions, age, physical conditioning, pre-existing conditions (heart problem they did not know about), etc. we might actually be able to attempt a comparison between people wearing the new shoes vs. the other brands. Even then, the nexus would be tenuous at best. A similar exercise would be needed to compare car fires between brands and types with any degree of validity. I don't have the time to dive into the stats. It was easy enough to Google [0][1][2][3] and do a quick scan: It is easy to see that young males are more likely to be involved in a car fire. There are statistics about different brands having different fatality rates (not necessarily related). Lots of fires are caused by running equipment. Lots of fires originate in the engine compartment. Mechanical and electrical failures seem to account for over 60% of fires. The point is simple: Far more extensive and detailed statistical work needs to be undertaken before anyone can conclude absolutely anything on the merits of any particular car or design as it pertains to potential to cause fires. Elon and his team are very smart. They know this. And this is why some of their marketing of late feels really dirty and beneath them. This is Tesla reacting to news that affected their stock price and, potentially, buyer sentiment, with marketing rather than the truth. Are Tesla's safer than all gasoline cars? That question is probably not an easy one to answer at all. There's the potential for a theoretical sort of an answer based on design. For example, there are no fuel lines to rupture. Does that mean it is safer? Hard to say. What do you compare that to? Perhaps you can list all the potential sources of ignition and sort them by probability and MTBF? Not sure. Of course, then you have the real-life probability. Once you get a million cars on the road with all kinds of people, driving in all conditions, roads and levels of maintenance and neglect things can change dramatically. If I remember correctly Tesla has somewhere in the order of twenty thousand. There's a reason we see major car companies recall hundreds of thousands of cars every so often. Shit happens. Design error are made. And it can take time and a massive installed base to discover them. THE TRUTH OF THE MATTER is these are the kinds of tests electric cars will have to endure over a period of time in order to reach wide adoption. Despite what's been said here a full tank of gasoline is far safer than a fully charged battery pack with enough energy to go 300 miles. Before anyone mauls me, consider how many gasoline cars have been driven and, yes, crashed, world-wide since gasoline cars came into mass production. Not last year. Since forever. There have probably been millions of accidents without fires, even with fuel leaks. There's probably no imaginable way to compare the two at this time. We simply don't have enough data. And, no, linking to a horrible crash video on youtube involving gasoline igniting does absolutley nothing to support arguments on either side. The one issue with electrics that is not spoken of is the fact that you have a several hundred volt high energy system that could very well electrocute passengers. I fully expect that to happen one day (in general, not necessarily Tesla). If and when that happens you can bet it will set the breaks on electrics for a while and relevant stocks will plummet. I still believe electric cars are the future. We simply need to go though the evolutionary process that will make them really safe for hundreds of millions of electrics to share the road. What happens when you have a pile-up of ten or twenty electric cars on a fogg-covered highway? A pile of mangled wrecks with 400 Volt high energy systems is unimaginably dangerous. I can think of a few horrific scenarios under those conditions. At some level part of me thinks that fuel cells are the future, not batteries. Having something relatively benign that can leak out would be a good thing. A few months ago there was a horrific crash in my neighborhood. This 18 year old kid decided it was OK to go 100 miles per hour on this avenue. He lost control and plowed into a bunch of cars parked by the side of the road. He absolutely destroyed seven of them before coming to a stop. Most of the cars were mangled beyond recognition. He was driving an SUV with a lot of mass. His SUV was nearly cut in half and impaled into one of the cars to a degree that made it difficult to see where one car started and the other ended. Almost like taking two lumps of play-doh and mixing them together. No fire. Gasoline all over the place but no ignition at all. He hit the first car, fused into it and the "ball" formed by the two cars proceeded to destroy the other six. Absolutely amazing display of how much kinetic energy was dissipated. Had this been eight fully-charged electric cars I am almost certain there would have been a horrific fire as well as the potential for absolutely impossible to describe electrocution of some of the passengers. And, to make matters worst, it would have taken the rescue crew far longer to remove the victims as they would have to be worries about electrocuting themselves and the victims (at the very least). Until there are enough electric cars on the road to have a massive pile-up accident [4] where most cars are electric we will not really understand the practical reality of a world where every car on the road is electric. Imagine having to walk out of a one hundred mangled car pile-up where every car has a battery pack storing enough energy to drive 300 to 400 miles and they are wired to produce hundreds of volts. I can't imagine anyone who understands electronics and electricity that would tell me all would be well after looking at the pictures from this accident [4] if all cars were electric. Look at pictures 1, 8 and 11. No fires. Gasoline isn't all that bad in this regard. [0] http://www.usfa.fema.gov/downloads/pdf/statistics/v13i11.pdf http://www.usfa.fema.gov/downloads/pdf/statistics/v13i11.pdf [1] http://www.usfa.fema.gov/statistics/reports/vehicles.shtm http://www.usfa.fema.gov/statistics/reports/vehicles.shtm [2] http://www.chandlerlawgroup.com/library/national-vehicle-fire-statistics.cfm http://www.chandlerlawgroup.com/library/national-vehicle-fir... [3] http://www.statisticbrain.com/driver-fatality-stats-by-auto-make/ http://www.statisticbrain.com/driver-fatality-stats-by-auto-... [4] http://www.cnn.com/2013/09/05/world/europe/uk-huge-chain-reaction-crash/index.html http://www.cnn.com/2013/09/05/world/europe/uk-huge-chain-rea...

sgustard 13y ago

If Toyota owners got one of these emails every time one of them caught on fire it would be sort of a downer, so I guess you only have a few chances to make it a PR event.

uladzislau 13y ago

The title is missing word "incident". My first thought was that Tesla has a new model "S Fire".

kintamanimatt 13y ago
A car called Model S Fire would be like a software package called Microsoft Crash.

mixmax 13y ago

My boat's hull happens to be made of 1/4 inch metal plate (6mm) which is apparently the same as the protected underside of a Tesla. I've hit a concrete block, gone aground a few times and generally have a bit of excperiencing with impacting hard immovable objects with a vehicle protected by a 1/4 inch metal plate. It takes a LOT of force to pierce 1/4 inch plate. My boat weighs 12 tons, and it hardly has a dent from the collissions I and previous owners have been in.

nubela 13y ago
your point being?
- mixmax 13y ago
  that if a tesla has a 1/4 inch protective plate seperating the batteries from the road it's a safe vehicle indeed. I was simply sharing my personal experience with ramming 1/4 inch plated vehicles into hard immovable objects to give some perspective as to what kind of strength we're talking about.
- GeneralMayhem 13y ago
  The fire in question involved the piercing of a 1/4" plate protecting the battery from below. If that's a thick enough plate to protect a 12-ton boat, which has more momentum than the Tesla even at much slower speeds, with hardly a dent, then the Tesla incident was very, very out of the ordinary.

anoother 13y ago

As much as I admire the work Tesla and Elon Musk are doing, I can't help but feel that the press releases issued by the company are at times overly defensive. We all know there is negative rhetoric bouncing around about this incident. It seems to me that, precisely because of this, there really isn't a need to write in such a manner—trying to block all possible avenues of attack as if one is a afraid of what will be written in response. The tone, to me, betrays insecurity, and this seems something at odds with the bullish, innovative nature of the non-PR aspects of the business.

senthilnayagam 13y ago

Stakes are high, for sure Elon Musk & Tesla would review its design, would possibly add protection for these type of accidents. Will any other gasoline car manufacturer be willing to participate in such crash test what model S encountered, I doubt anyone will.

tn13 13y ago

The following statement is wrong at many levels. "That equates to 1 vehicle fire for every 20 million miles driven, compared to 1 fire in over 100 million miles for Tesla. This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla!" - All Tesla cars are new and almost all of them have superior drivers. - They drive their cars only on certain roads where as Gasoline cars are almost everywhere. - You can not compare 100m sample set with 2 trillion size sample set.

zalew 13y ago
And he forgot to mention many gasoline car fires aren't due to gasoline ignition, but electrical failures or material melting (plastic/glue), etc. The only common case of gas ignition is static electricity while filling up, f.ex. re-entering the car while wearing a sweater (you can even smoke a cigarette while filling up, it's the spark that's dangerous). Closed gasoline tanks have been safe for decades and contrary to what we see in movies it's close to impossible to fire them up even in serious car crashes, especially when they're full. There is even a method for extreme freezes (-30-40'c) to light a small fire under the tank to help the fuel flow to start the engine (especially needed for diesels and low quality gasoline) and the only fires due to that are when the stupid owner didn't realize his tank or other parts around are plastic (which's quite a modern day problem).

bsullivan01 13y ago

Fire happens. Maybe Tesla performs better, maybe not but cars do catch fire. I, however, will not be buying Elon's explanations simply because he seems like a cheesy salesman and a media whore. http://www.bloomberg.com/news/2013-04-02/tesla-to-begin-model-s-financing-with-u-s-bancorp-wells-fargo.html http://www.bloomberg.com/news/2013-04-02/tesla-to-begin-mode... (Knowing the Elon is the Sun God among many here, I want to say this: I do not particularly care about karma, I'm saying 100% of what I am thinking.)

nodesocket 13y ago

I wrote a blog post on this last night (Tesla model S and the three laws of robotics). http://justink.svbtle.com/tesla-model-s-and-the-three-laws-of-robotics http://justink.svbtle.com/tesla-model-s-and-the-three-laws-o...

001sky 13y ago

A little closer reading of the report[1,2], shows that only 26,000 automobile fires occur on public highways. That makes Tesla's single datapoint worse than a conventional Auto. All cars: 1 fire per 116 million vehicle miles/year Tesla: 1 fire per 113 m vehicle miles/since inception Obviously, the Model (s) being a newer Tesla model does not have the full historical amount of "Tesla" Miles as the denominator. [1] http://www.nfpa.org/~/media/files/research/nfpa%20reports/vehicles/osautomobilefires.pdf http://www.nfpa.org/~/media/files/research/nfpa%20reports/ve... [2] Furthermore, only 2% of non-deliberate fires start in the fuel line or fuel tank of a normal vehicle

zw123456 13y ago

Tesla, recall is coming, that is obvious. You will be forced to put in stronger armor underneath. So drop the price by $10K, or do the recall sooner. Either way that is the reason for the stock hit, people know one or the other or both are coming.

Kiro 13y ago

Why are people on HN so keen on defending Tesla at all cost?

hkmurakami 13y ago

Totally thought this was a name for a new model S model, a la kindle fire.

fus 13y ago

"Had a conventional gasoline car encountered the same object on the highway, the result could have been far worse." Diesel-powered car would be much safer, since oil requires something like a wick in it to burn. It's hard to argue with Tesla's statement, since argument is true; but it doesn't include this issue in electric vs ICE vehicle competition.

jmount 13y ago

I've blogged a fun writeup of the math in the (unimportant and actually against Tesla) formal bias in evaluating a failure rate right after the first failure: http://www.win-vector.com/blog/2013/10/estimating-rates-from-a-single-occurrence-of-a-rare-event/ http://www.win-vector.com/blog/2013/10/estimating-rates-from...

oddshocks 13y ago

He is just great

oddshocks 13y ago
Downvote me for my opinion you HN haters bring it on