Ever wondered just safe electric cars are, like Tesla for instance. - Page 1
Forum section: electronics / general

author: Specmaster
author_rank: Super Contributor
timestamp: November 23, 2018, 08:07:39 pm
content: Perhaps its time to rethink this whole electric car thing through again.Imagine this happening in a garage full of electric cars and the chain reaction???

author: coppice
author_rank: Super Contributor
timestamp: November 23, 2018, 08:09:52 pm
content: Quote from: Specmaster on November 23, 2018, 08:07:39 pm404

author: bd139
author_rank: Super Contributor
timestamp: November 23, 2018, 08:13:19 pm
content: Petrol scares the shit out of me more.https://www.bbc.co.uk/news/uk-england-merseyside-46290095

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 23, 2018, 08:15:02 pm
content: Quote from: Specmaster on November 23, 2018, 08:07:39 pmYou mean how petrol cars aren't full of oil and literal fuel?

author: Specmaster
author_rank: Super Contributor
timestamp: November 23, 2018, 08:16:35 pm
content: For some reason the link has become corrupted and I'm struggling to find the original video, I'll keep looking, watch this space

author: oPossum
author_rank: Super Contributor
timestamp: November 23, 2018, 08:22:28 pm
content: Fixed link

author: Specmaster
author_rank: Super Contributor
timestamp: November 23, 2018, 08:24:20 pm
content: Haha, we both resolved it then.

author: dr.diesel
author_rank: Super Contributor
timestamp: November 23, 2018, 08:37:43 pm
content: Actual fault, no BMS, overcharged? How grossly overcharged until those burst into flames?Not toys, those guys are lucky, hope they learned their lesson before a customer gets hurt with poor engineering/practices.

author: Specmaster
author_rank: Super Contributor
timestamp: November 23, 2018, 08:44:40 pm
content: While that maybe, the point is in a RTA and a fire results and those batteries then become lethal sending flaming bombs out in all directions.Do a google search for Tesla fires, these heaps of them.

author: bd139
author_rank: Super Contributor
timestamp: November 23, 2018, 08:46:19 pm
content: They don't though. They burn in a controlled fashion through the vent ports in the side of the packs.Anyway, I'll take the Tesla please:And definitely not the Vauxhall Zafira which was known for spontaneously combusting just randomly.You are soooooooooo much safer in an EV. If it goes up in flames the reaction takes minutes not seconds. You have time to get out or be extracted.

author: Specmaster
author_rank: Super Contributor
timestamp: November 23, 2018, 08:49:03 pm
content: But thats a frontal accident, batteries are under the boot (trunk) and rear seat I think.

author: bd139
author_rank: Super Contributor
timestamp: November 23, 2018, 08:54:05 pm
content: The battery spans the entire underpan.The point is you an hit that battery and it will just vent like this.Most of the auto infernos you see aren't directly due to the battery which will vent safely but because the plastics and tyres caught fire.There is a terminator 2 type melted lump in the middle of my road where a petrol car caught fire...The reaction is quite slow. It isn't an explosion. This is petrol:Imagine that in an accident...

author: Specmaster
author_rank: Super Contributor
timestamp: November 23, 2018, 08:55:36 pm
content: Yep Vauxhall Zafira is not the only car known for that either, many French cars used to self ignite overnight.

author: bd139
author_rank: Super Contributor
timestamp: November 23, 2018, 08:56:32 pm
content: Hopefully not Citroens

author: Specmaster
author_rank: Super Contributor
timestamp: November 23, 2018, 09:02:50 pm
content: Maybe this might explain where the rumour about french cars came from, it was mentioned on Top Gear and you never really know when they something if its fact or said for comedic valuehttps://www.theglobeandmail.com/report-on-business/deadly-self-igniting-iranian-made-cars-causing-concern/article676501/

author: hans
author_rank: Super Contributor
timestamp: November 23, 2018, 09:56:02 pm
content: We are already pushing out millions of Lithium batteries into tablets, smartphones and laptops. Only a handful of them spontaneously self combust (except for the Note 8 phone), so I don't think it's a chronic problem.But yeah, any chain reaction would be messy. I think it's pretty common to LiPo batteries (that are a bit more unstable than Lithium-Ion) in special bags or containers that should contain the fire when it is stored.In contrast.. A combustion engine is designed to operate on the principle of combustion. We pour 50 liters of combustible liquid (that quickly evaporates as a toxic gas) into a tank, that is pumped into a specially designed metal block with combustion chambers that house controlled explosions. We need an thermostat and active cooling system to make sure this system won't overheat when it's just running stationary. The designed operating temperature is in the order of 90 to 110C, plenty hot for nasty burns. The exhaust fumes of a car are fed and filtered through an exhaust pipe, where toxic concentrations of oxocarbons (and the like) are still present. In addition in a diesel engine, if any fuel line leaks or hose starts to erode due to aging, it may light the whole engine bay no fire in no time. This is (or was?) actually not uncommon with older buses (that are poorly maintained) in the Netherlands.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 23, 2018, 11:32:43 pm
content: Wouldn't it make sense for garages (both residential and commercial) to have fire sprinklers? (Anyone remember when "First On Recall Day" had problems with a switch that would short at random and start fires?)

author: Wan Huang Luo
author_rank: Regular Contributor
timestamp: November 23, 2018, 11:49:57 pm
content: Quote from: Specmaster on November 23, 2018, 08:07:39 pmit was a matter of time before that brainless idiot got himself into trouble. I have no kind words to say about him or the work he does.

author: rstofer
author_rank: Super Contributor
timestamp: November 24, 2018, 12:26:56 am
content: Quote from: NiHaoMike on November 23, 2018, 11:32:43 pmThis is becoming common on new residential construction. Older homes won't have sprinklers.I don't give the issue a moment's thought. I had a Chevy Spark EV for 3 years and I've had a Chevy Bolt for nearly 2 years. Both have been excellent cars.I haven't seen any REAL statistics. For example, of those cars crashed in a certain way, how do battery car fires compare to gasoline cars. It's pretty easy to say "Well, it's known that Tesla cars go up in flames!" So did the Pinto! And so do many other gasoline cars in certain types of accidents. Happens all the time.According to this article, there has never been a battery fire in a Chevy Volt or Bolt:https://www.torquenews.com/1/why-tesla-batteries-catch-fires-bolt-and-volt-batteries-dontThere are similar articles re: Chevy battery construction all over Google.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 24, 2018, 12:43:07 am
content: The problem with sprinklers is that they do a lot of damage. In this case it would have been significantly more damage than the fire caused without them. They're only useful to prevent a total loss.

author: amyk
author_rank: Super Contributor
timestamp: November 24, 2018, 01:50:43 am
content: Sprinklers in a parking lot wouldn't do much damage to non-burning cars --- which normally have to survive being rained on anyway.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 24, 2018, 02:26:41 am
content: Quote from: amyk on November 24, 2018, 01:50:43 amSprinklers tend to be inside. I don't think I've ever seen sprinklers in a parking lot. Besides, this was a workshop. That's a huge bill when dowsed.

author: amyk
author_rank: Super Contributor
timestamp: November 24, 2018, 02:33:35 am
content: I was referring to the question of how to stop chain-reactions in dedicated parking garages full of cars.

author: Towger
author_rank: Super Contributor
timestamp: November 24, 2018, 07:15:05 am
content: Quote from: Specmaster on November 23, 2018, 08:55:36 pmA neighbours couple of week old Merc spontaneously combusted when parked outside their house. Cause unknown, but Merc given them a new car, so no messing with insurance.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 24, 2018, 08:22:53 am
content: Quote from: amyk on November 24, 2018, 02:33:35 amWhile a chain reaction can easily happeninsidea battery pack, the risk of it happening between two battery packs at least a meter away from each other, is extremely small.The energy release of a lithium ion fire is, ultimately, notthatmassive (I remember seeing analysis that when this happens with packaged cells, the energy release is the same order of magnitude than the cardboard packaging material combusting). The order of magnitude we are talking about is something like 100-200kWh released within 5-15 minutes, equivalent to a good big bonfire. An equivalent gasoline fire would be around 500kWh (for 50 liters or 13.2 gallons) possibly released within a minute or even less; yet, AFAIK it's rare that gasoline cars pop up in a chain reaction, even though gasoline car fires are extremely common and happen all the time (which is why, btw., all the big public parking garages have sprinklers, at least here... I think it's mandatory). Actually random gasoline car fires are so common they are not typically reported as single cases by the media, they go into statistics only.Now, the issuewithinthe pack is that the neighbor cell start to run away at around 160 degC. The problem: the cells are justmillimetersfrom each other - or completely in contact, with no thermally protective material - and in a big pack, it's a dense 2D matrix, so once you have a few cells going, they heat up the neighbors from multiple sides. The heat has nowhere to go, except to the other cells.For example, IIRC, Tesla has claimed they have analyzed their pack can withstand any single cell running away - this makes sense as they have small separations (5mm? Not much, but more than usual) between the cells, and cooling pipes running between them. So, the fires have been caused by, for example, large enough physical penetrations to put multiple neighboring cells into thermal runaway.In any case, this gives you theideahow close the heat source needs to be in order to cause the damage. Conceptually, you can simulate this with candles: when you really lump them together in a large matrix, there is a reported risk of a chain reaction, but once you separate them byan inch, that problem is gone.Cars tend to be separated by at least half a meter, and the battery packs tend to be enclosed in metal, and don't tend to protrude near the car's external measurements. So, the pack-to-pack distance would be around one meter a least, and there would be multiple metal walls between, spreading the heat. Comparatively, take a modern fire stove; it has double steel wall with an outer envelope, with air cooling channels inbetween. I can safely tape an 18650 cell to such a stove, despite the >1000 degC fire going on inside, just 10 cm away!While a burning car might set the neigbor's wheels on fire, no electric vehicle should have such a massive design failure that the wheel fire spreads to the battery pack (the opposite can happen).And, when the fire is in open place, convection quickly cools and mixes the air, moving the heat to a larger area. If there is any hotspotting, it tends to be rightabovethe fire. So maybe with tightly stacked cars without solid floor inbetween, as in a large multi-car tow truck / car transport, this could be a problem?Within separate cars with enclosed battery packs, it would requirevery strangecircumstances to bring any cell over its runaway temperature. Might be possible with an unfortunate vent hole directedrightat the worst direction where a poorly protected battery pack of the another car sits, but cars seldom are parked within centimeters of each other, so the flame would need to somehow be extremely focused, and basically direct the full combustion energy of the pack to one place, in a narrow beam that exactly hits the battery pack of the next car. And for this to become a massive chain event of more than two cars, this unfortunate condition would need to repeat with every car in the line.

author: doobedoobedo
author_rank: Regular Contributor
timestamp: November 24, 2018, 02:49:51 pm
content: They were charging without a BMS. I think the moral of this is don't be an idiot.

author: Specmaster
author_rank: Super Contributor
timestamp: November 24, 2018, 04:09:20 pm
content: Quote from: doobedoobedo on November 24, 2018, 02:49:51 pmDo you actually know they were charging without a BMS? I don't recall ever seeing the car being disconnected before pushing it out of the garage!I think it was just sitting there with nothing going on when it burst into flames.

author: Specmaster
author_rank: Super Contributor
timestamp: November 24, 2018, 04:26:35 pm
content: Quote from: hans on November 23, 2018, 09:56:02 pmYou are correct about buses catching fire. I used to be an engineer on a bus company with about 1000 buses and the problem with buses is poor maintenance and it shows up on under floor engines, which lay on their side. Diesel and engine oli leaks, though tiny, build up a small pool on the crankcase castings, dirt and fluff etc settles in this. The pool gets quite hot as the engine is running for hours on end and all it needs is a spark or discarded cigarette butt that is still glowing to be blown / sucked into this pool and wooff you have a fire. I have examined many buses after they have had a fire and in case the cause was the same. None of the buses in my care (about 160) ever caught fire because they were properly maintained and the engines regularly engines washed to prevent this build up occurring.

author: nctnico
author_rank: Super Contributor
timestamp: November 24, 2018, 05:04:16 pm
content: Quote from: doobedoobedo on November 24, 2018, 02:49:51 pmAnother failure mode which can cause spontaneous Li-ion fires is when cells have been discharged too deep. This causes 'growth' of crystals (dendrites) which puncture the seperator layer. This is a ticking time-bomb with a random timer.https://www.electronicproducts.com/Power_Products/Batteries_and_Fuel_Cells/What_are_dendrites_and_why_do_they_cause_fires_in_lithium_batteries.aspxChances are they used an old battery pack has been mistreated or discarded for no longer being safe.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 24, 2018, 07:08:33 pm
content: Quote from: doobedoobedo on November 24, 2018, 02:49:51 pmI understand. If I give you a box which says "BMS" on the top, it solves the problem. If you don't buy the box, you are an idiot. Is this proper way of engineering such safety-critical systems?The sad part is, the more serious an incident is (such as this), thelesslikely people seem to be willing to do a proper root cause analysis - or evenspeculate properly. For some reason, people get scared, and our brains seem to have this failure mode of fearing analysis when exactly that would be your best friend - instead we resort to easy simplifications and finding clear scapegoats - having no actual information doesn't prevent you from faking it. Typical suspects are, depending on "which bubble you live in", that a li-ion fire is either caused by a BMS, or by the lack of it. When properly analyzed,eithercan be the actual reason, but most of the reasons are neither of these two.Speculation is all good, to find ideas, but in cases like this, some real information is needed, and we should be honest about it when we are speculating.Here comes some speculation:Most typical reasons for catastrophic failures include improper manufacturing quality and physical damage (such as cell penetration). This is said to be a dismantled Tesla pack, so it should rule out cell quality (they would be Panasonic, one of the best you can get). This in fact makes the incident really interesting - the root cause is probably some of the less frequent stories.After these two obvious causes, the next on the line might be using cells that have died by severe overdischarge. As nctnico explains, copper dendrites may appear. There are so-called proper "revive" algorithms for slightly overdischarged cells (basically, very slow charge such as C/100 with voltage monitoring - AFAIK the idea is to have the dissolved copper go back in the current collector where it came from, instead of forming said dendrites!) While officially supported by the manufacturers such as Samsung, it may still be better to just dispose of such cells, even if they are almost within limits.A proper BMS does not allow charging of a pack with a cell at, say, less than 2.5V. On the other hand, there are improper BMS ICs on the market from reputable manufacturers, which fail to follow the correct practices. For example, a certain TI product does the "revive conditioning" at C/10 when configured typically, and it's impractical to configure it below C/20. The conditioning charge is too fast, and the dendrite risk is real. People who blindly design in these trusted BMS products, are doomed. But like with any semiconductors (think about an opamp!), you need to understand the datasheet, all its parameters, and you need to understand the problem you are solving; no opamp datasheet guarantees it's suitable for a specific application. Now you would expect that application-specific ICs are suitable for their specific applications, but don't take it for granted; these ICs are not safety-certified finished products;the BMS designerdesigning in the chip is the one who is supposed to be in that position, but often they don't know this!So, as you can see, the next speculation target might be "the failed BMS" story. Yes, you read correctly, this is the case where either the BMS is to blame directly, or the misuse of a BMS, coupled with the false sense of security in using one. When people charge or dischargewithouta BMS, theyusuallyltend to have a clue, set a charger CV voltage setpoint properly, for example. With a BMS, a lot of utterly dangerous advice exists, even from the manufacturers. The most fundamental issue is the "just use BMS and forget about it" cargo cult attitude, as demonstrated here, again.As a concrete example, many BMS manuals and brochures instruct that with their BMS, you can use "any" charger, even "stupid" current sources, because the BMS "controls" the charging. In an ideal model this works, as long as:1) the BMS never malfunctions - when wired like this, it stops being a redundant safety system, and becomes the only critical loop, and it tends to be a more complex, more error-prone system, compared to a simple resistor divider limit in a power supply;2) the BMS is actually connected properly, so itcanphysically stop the charging - preferably two ways, soft "charge enable" and driving the main contactor. No joke, this mistake really happens. It doesn't help if an unconnected "charger disable" signal screams while the cells start approaching 5 volts.A proper use of BMS shoulddefinitelyinclude using a charger with a properly adjusted voltage setpoint, so even if the BMS fails, the charger just charges the cells fully as a single pack (like you do without a BMS). Even with a slightly imbalanced pack, this isunlikelyto cause dangerously serious damage, so it acts as an extra safety layer. Independent safety layers are great! That's where an independent BMS system can really shine. Don't ever waste this opportunity by trusting it completely as the only mean!With recycled cells, you never know the full story of the cells. For example, if these packs are dismantled from a crashed car, mechanical damage is well possible. Or, a previous owner has charged a dead cell, causing those dendrites, and the current owner cannot know this as the cell isn't below low voltage limit anymore.Or, it may be a combination, for example, too high of a charging current to a deep-discharged cell, combined with a physical shock, combined with it being charged fully.Speaking of dendrites, lithium plating and lithium dendrites do happen near full charge, by:1) overcharge by voltage - this is easy to define and easy to avoid.2) charging current too high, combined with high state-of-charge, combined with low temperature. This is a more complex function.This is a different mechanism from overdischarging, which causes copper current collector to dissolve, letting copper ions into the electrolyte.

author: Specmaster
author_rank: Super Contributor
timestamp: November 24, 2018, 08:07:09 pm
content: @Siwastaja, thank you for the detailed information, it does throw some useful light on the subject and shows the dangers of jumping to what I believe was the wrong conclusion about not having a BMS in circuit. Unless I fell asleep and failed to see that or hear it mentioned during the videoI have an open mind as to what caused this fire and as the OP in this case and regardless of what the garage may or not have done to this vehicle it serves as a warning and an eye opener that these cells / batteries are highly dangerous and that before we throw out altogether the use of fossil fuels that we still have a massive way to go yet with an alternative to fossil fuels which have had decades of research into making its use and storage safer than ever.Yes, I understand that conventional cars do catch fire, I have seen this first hand many times but I have yet to see one explode beyond the windows blowing out and the tyres exploding, generally the fuel tank seems to do a good job of protecting the bulk of the fuel becoming involved in the fire. You can see examples of this on major highways when there is a car fire, they tend to keep the highway open if possible albeit maybe just a single lane passed the incident. Surely if there was real serious danger of the fuel tank exploding they would shut the highway down completely and impose a no go zone around it?In that particular video there was individual cells exploding and becoming red hot flaming projectiles going in all directions which could result in personal injuries and also spreading the fire far and wide. Even if in a normal production car, that might have prevented that from occuring to being encased within a metal shell, there will always be examples of people building custom vehicles, where a metal encasement might not be used as in the video.I'm not an expert in this area by any means, but it does strike me as we need to understand a lot more about these systems and how they behave when under stress etc before we declare that all new vehicles will be electric and also just how do we extend the range to at least equal to that of tankful of petrol or diesel and again a quick and simple method of recharging and be on your way without having to stop for a considerable time waiting batteries to recharge.

author: doobedoobedo
author_rank: Regular Contributor
timestamp: November 24, 2018, 09:43:05 pm
content: Quote from: Specmaster on November 24, 2018, 04:09:20 pmThey admit it at the end of the video also if you read some of the comments it's pointed out that there's a short cut at around 3:13 where a cord is connected then suddenly isn't.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 24, 2018, 09:50:25 pm
content: Quote from: Specmaster on November 24, 2018, 08:07:09 pmThese "projectiles" have fairly low kinetic energy, they barely fly a few dozen meters. It's comparable to someone throwing the cells around.Anymetallic battery box completely stops them from flying. No, they won't penetrate the metal. Maybe paper.But yes, in development labs / hobby this is really dangerous, since this kind of flaming projectile can set anything on fire, even if you were careful to make sure there is no flammable material right next to your battery pack.(Personally, I use a sheet metal box for this reason. It doesn't need to be anything special. They are not bullets.) A box also distributes the heat by not allowing the flames to shoot out from a single place.QuoteOh, IMHO, this isn't a problem, because there is a direct replacement type relationship here (i.e., an upgrade), and the original situation sucks so much it's easy to improve on. Depending on where you get the exact figures, electric vehicles reduce the number of vehicle fires and their severity either a bit or by a lot. It's an improvement anyway.It's of course sad it isn'teven moresafe, that would be great. But it's not a disadvantage, either, since it's at least similar or better anyway.It's just that a gasoline car burning is a completely everyday action everywhere, it's so common that no one's interested at all. We need to compare to that. People die because of that in significant numbers, all the time. This is of no interest to anyone, either. Why should it? A much more relevant issue is people dying in traffic accidents due to other causes than fires.Of course, we would all like to have safer battery technology. It would be so cool. Burning electrolyte and thermal runaway at 170 degC sucks.I don't wan't to downplay the issue. It's a significant thing. If it wasn't important, I would be cool with people freaking out, like they do on unimportant things like the fact that some celebtrity is with another celebrity. But instead, because this is actually important, I want to see some real improvement, which comes through proper root cause analysis and fixing the process.

author: fsr
author_rank: Regular Contributor
timestamp: November 24, 2018, 10:08:20 pm
content: Yep, they say that in the video "no BMS and no cooling":https://youtu.be/WdDi1haA71Q?t=691About sprinklers in the garages. I suppose that they would need to have a special liquid, because puring water into a damaged ~150 kw battery pack... i don't know, to me that sounds like a lot of trouble. This battery packs have like 400v output voltage. No fooling around with this things.You cannot "just improvise" how to charge/use those battery packs, just like you better follow instructions when charging a gasoline tank. Like: no smoking when surrounded by toxic, explosive gases. You wouldn't replace a gasoline tank with a cardboard box, right?

author: doobedoobedo
author_rank: Regular Contributor
timestamp: November 24, 2018, 10:13:05 pm
content: @Siwastaja - I tend to call any kind of charge controller a BMS.From the way the cells all basically started going off at once I would say they were _all_ pretty hot before the very first one caught. For me the most likely cause is that they were overcharged to the point of failure. From what I can tell from the video about the size of the cable attached I would also speculate that it was over-voltage rather than over current.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 24, 2018, 10:24:48 pm
content: Quote from: fsr on November 24, 2018, 10:08:20 pmI recall even Tesla recommends using water to extinguish a battery fire.

author: raptor1956
author_rank: Frequent Contributor
timestamp: November 24, 2018, 10:25:53 pm
content: Overcharging batteries is bad ... who knew?A friend I worked with was also the Chief of a voluntary fire department and had to respond to a number of auto accidents that resulted in a gasoline fire -- the effect that has on the occupants that can't escape is horrific. If I had to chose between a battery fire or a gasoline fire in my car I'd chose the battery every time given the slower energy release and generally lower total energy content.Brian

author: Siwastaja
author_rank: Super Contributor
timestamp: November 24, 2018, 10:32:47 pm
content: There clearly is a (partially) installed cell-level BMS in the pack, as you can see from the massive amount of thin wire spaghetti, which probably belongs to a centralized BMS system (per battery module). Assuming this belongs to the original BMS, probably the unit itself is removed, but the wiring left behind. This kind of spaghetti wiring is a possible risk as well, and needs to be properly fused and insulated."No cooling" is meaningless. Such a pack in such a small and low-power vehicle certainly doesn't need any kind of active cooling, the discharge and charge rates are going to be low. And, even cooling cannot replace temperature sensing, which is important in any case, because even cooling can fail (and is hard to model perfectly). Tesla uses water cooling to equalize the battery aging, and to make massive discharge rates (such as 2C) and then, without cooling time, high charge rates (around 1C), possible. But Tesla is special, they are high-performance - most battery packs don't use active cooling, but simply cool through the surface area of the pack. I'm 100% positive that the "lack of cooling" is not the issue here. To give you an idea of magnitudes, cruising at 10hp or 7kW power and charging from 3kW wall socket would mean, at 98% battery efficiency, 140W thermal output, on a battery pack surface at least a square meter!OTOH, if you want to design cooling to prevent thermal runaway in failure conditions, that's gonna be hard. Even Tesla seems to have failed it (despite a lot of great engineering that went into it).Temperature monitoring, though, is averygood idea. It's one of the central parts of a proper battery management system, but it doesn't come "automatically" by getting a BMS. In such a big pack, you may want to use more sensors than your BMS has inputs for. The BMS I designed for a 100s system had support for 200 temperature sensors, for example."Use a BMS" may be the stupidest thing you can say. It's not something you just buy and use. It's a system, and a process. It's automation technology as well. It's not a silver bullet, and it isn't a lab safety device people seem to think it is.In such a large pack,youare the one who "builds" the BMS, around the pack - typically using some already existing solution as components. For example, you need to install sufficient number of thermal sensors, you need to know exactly how to fuse the voltage sense wires and how to insulate them when they cross higher voltages in automotive environment, where rubbing may happen. You need to understand the fusing, contactor ratings, etc, and it's not trivial. BMS adds its own limits: for example, it may become forbidden to add a fuse or a safety disconnect to a certain links.So just getting a BMS and somehow gluing it together and calling it a day is a recipe for total disaster. Well, at least an equal disaster than doing random thingswithouta BMS. The BMS is not the point - the point is to understand and do the Right Thing.Water - a lot of it - is the right, and the only proper way to fight lithium ion fire, it's the only way to remove the heat power output at sufficient rate. Since the cell chemistry contains the oxidizer (in LiNiCoAlO2), any CO2/powder/chemical/foam/halon distininguishers are completely useless in stopping the reaction. They can, of course, distinguish the surrounding materials that already caught fire.QuoteMaybe, maybe not. To me, it looks like initially they go off at about 20-30 second intervals and spread slowly, it gets quicker once it's outside. It's hard to see, really because each single cell popping looks quite dramatic already. (Note there are cuts in the video.)While itispossible that the full pack was grossly overcharged, so that all cells would be already hot due to overcharging, I don't feel it's likely. Why?1) The level ofacutelydangerous overcharge, where temperature starts to rise, is somewhere around 4.6V/cell. The voltage rise is fairly linear from 4.2V;2) With such a massive pack, unless they have a massive charger, charging is going to be slow, so reaching that level would take time,3) It would be indeed quite stupid to set the charger to output such a high voltage, and forget it completely for such a long time.It's not impossible, just other failure modes seem more plausible, including gross imbalance leading the really severe overcharge of some cells, prior damage - physical or overdischarge, etc.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 24, 2018, 11:06:56 pm
content: Quote from: blueskull on November 24, 2018, 11:01:51 pmBut the EV battery isn't 200kWh. My number 100-200kWh included all that already, for a typical kinda-average 30-50kWh battery. This isn't very precise since I have seen quite different numbers for this total combustion energy ratio, but anyway, it's the correct order of magnitude and it's very unlikely to be over 200kWh. I could have stated this originally to be clearer, but I did assume everyone knows there are no EVs with 100-200kWh batteries so the number must include something else...

author: nctnico
author_rank: Super Contributor
timestamp: November 25, 2018, 12:10:03 am
content: Quote from: raptor1956 on November 24, 2018, 10:25:53 pmThe problem isn't the gasoline but the flammability of the interior. Besides that the fire/heat won't kill you but the smoke will. The gasoline is safely contained within the fuel line and the fuel tank (which is outside the passenger compartment for obvious reasons). This doesn't mean a fire in the engine bay can't reach the interior but it is not like burning gasoline is sprayed into the interior.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 25, 2018, 02:29:32 am
content: Quote from: nctnico on November 25, 2018, 12:10:03 amYeah.Also note that (and I still hate diesel engines!), diesel fuel doesn't burn easily. Not nearly as easily as gasoline. Just an additional thought regarding diesel cars.That said, most decently recent gas engine cars (not diesel) that have a decent score at crash tests will survive pretty violent crashes without catching on fire. Let alone self-ignite.Decades ago, that was not an unusual event, and incidently was most often due to an electric fault setting the car on fire...but that has become more the exception than the norm nowadays.The most cars catching on fire lately are those that are set on fire by offenders on new years' eve or during violent riots. And I'm pretty sure in those events, an EV can be set on fire almost as easily as any other...

author: wraper
author_rank: Unknown
timestamp: November 25, 2018, 02:42:12 am
content: Quote from: SiliconWizard on November 25, 2018, 02:29:32 amStatistics say that chance your usual ICE car will catch fire order is of magnitude higher than Tesla.https://www.statista.com/statistics/377006/nmber-of-us-highway-vehicle-fires/170 thousands of car fires annually in US alone but nobody cares. But all of the news about some poor Tesla.QuoteJust a small percentage by statistics.https://www.usfa.fema.gov/downloads/pdf/statistics/v19i2.pdf

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 25, 2018, 02:55:55 am
content: Is that sample group statistically relevant in size and adjusted for car age and class, which should impact the level of maintenance?

author: amyk
author_rank: Super Contributor
timestamp: November 25, 2018, 03:19:12 am
content: Quote from: nctnico on November 25, 2018, 12:10:03 amThis. All the Vauxhall Zafiras that burned started in the dashboard due to an electrical fault (and far too much flammable plastics around), not because of fuel leaks or anything related to the fuel itself.http://data.parliament.uk/WrittenEvidence/CommitteeEvidence.svc/EvidenceDocument/Transport/Vauxhall%20vehicle%20fires/written/47523.html...far too much flammable plastics. I've never seen a plastic blower motor until now.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 25, 2018, 03:22:44 am
content: @wraper: my considerations weren't directly comparing with EVs, but merely talking about gas and diesel cars. I don't think we have enough EVs in circulation and enough hindsight to make relevant statistics when trying to compare the respective risks, really. Doesn't make much sense at the moment IMO. So in the same vein, I would refrain obviously from stating alarming facts about risks that would be specific to EVs. Note that I didn't. There is just one and very real added risk with EVs it that IF they ever catch on fire (for any reason), there are specific precautions to take to extinguish the fire, and firemen should be trained for those, unfortunately there aren't enough of them that are trained as of now, at least in european countries. Failing to take the proper actions may lead to catastrophic events...In the same vein, obviously not all countries are equal regarding the kind of statistics you mentioned. Although exact statistics are not always publicly available (in France they aren't), a quick search showed me that in the US, intentional fires are something like 10 times less in proportion than in the UK for instance. And the ratio is even higher comparing to France, where some statistics give the overall proportion of intentional vehicle fires to be something between 50% and 60% (yes it has become very severe over here.)Another difference between countries is also related to the proportion of diesel cars. Whereas there are still relatively few in the US, they have become a majority in some european countries (which is a plague for many reasons). A plague, but as I said, diesel fuel doesn't burn as well as gasoline. So that also explains some of the differences during car accidents.As for the causes, your reports also place electrical failures as a significant cause of fires (outside of crashes), so my point regarding those seems to apply more widely than the others.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 25, 2018, 03:23:29 am
content: Quote from: amyk on November 25, 2018, 03:19:12 amYep.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 25, 2018, 08:36:31 am
content: Quote from: Mr. Scram on November 25, 2018, 02:55:55 amExactly. This is what makes the comparison difficult, and why we see numbers ranging between "the incident rate is about the same" to "EVs are ten times more safe".Another issue is we are comparing number ofincidents. We should be comparing num_incidents * average_severity. Actually, comparing death toll works quite well since it automatically takes care of this. But, battery-related EV fires resulting in actual deaths are so rare (is there even a single case yet reported?) that it's statistically irrelevant.The battery safetyisa real issue and it is wishful thinking to market or buy an EV based on assumption that it will be somehow much more safe against vehicle fire. It probably isn't, or even if it was, that's almost meaningless in the big picture.Even within the fire safety discussion, the difference between an EV and a gasoline car is not that big: it's still most likely the part that causes most of the damage and danger is neither the gasoline tank, nor the battery, but the interior, tyres and all plastic parts burning.The battery burns slower, with less energy released than a gasoline tank, but OTOH, it's very rare that the fire consumes the full amount of the gasoline, as people have pointed out - it just doesn't easily go off in the tank, and the fire just doesn't get "into the tank". When it happens, and it does happen, for example, by producing a leak in the tank due to an impact, the consequences can be large; much larger than in an EV battery fire. Car-to-car chain reactions were discussed earlier; with gasoline, it's theoretically possible, because even a fairly small leak makes it flow everywhere, and under the adjacent cars. Not saying this is common (the gasoline tank is well protected), but it does happen.So, the profile for these accident types are so different it's a classical apples-to-oranges thing. Gasoline increases the worst-case result beyond what an EV battery can cause, but such worst case is rare: the massive number of everyday gasoline car fires are not such cases. So does it matter so much?Then, compared to other types of accidents, the fire is not the #1 problem, or even the #10.Finally, in my opinion, it does not make sense to design crippled EV battery with ridiculouly bad driving range and massive weight "for fire safety". This route has been tried (for example, by advocating LTO and LFP chemistries - which has been a farce, since LFP cells have been in many battery fire incidents, so they are not even safer, and LTO is almost comparable to lead acid so enjoy your 50 kilometer driving range on your 200kg battery pack!)IMHO, designing highest energy density, lowest cost, lowest possible environmental footprint, battery tech is the right thing to do for the people of this planet, even if they were notperfectlysafe. It's just that sitting in any vehicle is a real risk, all the time. To put peoples (irrational) expectations to numbers (to show the irrationality), they are very worried about the issue that by replacing a gasoline tank with a battery, the dangerous car incidents don't go down, or go down by 0.1%, whereas people wouldlikethem to go down by 0.2% (by eliminating one non-dominating source completely, instead of just, say, halving it).It's just that our modern world is freaking out about any "safety" problem. The more obscure and improbable it is, the more it gets attention. Everybody totally freaks out when someone dies of electric shock (which is so damn rare). As a consequence, every engineer totally freaks out if a Chinese power supply has 3mm creepage distance when a standard calls for 6mm, even though it's extremely improbable someone would actually die because of it.Meanwhile, everyone is totally OK breathing in toxic, carcinogenic shit, eating shit, driving drunk, wasting their life in stressful unnecessary commuting, and so on. And, worse, if we suggest anything that makes our lives much better, and saves lives by millions (not only saving lives, but reducing slow, painful death and illness), but it has a chance of being related to a rare freak accident, it's a total no go. We rather go on with our habits of killing ourselves and each other slowly and painfully.We need to remember that almost all great inventions that ended up improving our quality of life and our health have a history of many "dangerous" experiments, and taking risks.Don't take massive risks. Don't do stupid things that are likely to cause an accident, with little gain. But, trying to eliminate all risks completely never works, and people who pretend to do that usually have a massive oversight about risk sources million times more severe. So, take some risks carefully. Analyze and learn, instead of freaking out...

author: wraper
author_rank: Unknown
timestamp: November 25, 2018, 10:31:54 am
content: Quote from: Siwastaja on November 25, 2018, 08:36:31 amhttps://electrek.co/2018/09/11/tesla-fleet-9-billion-electric-miles-revolution/And only very small number of them experiences fire, usually after mechanically damaging battery. While there are 253 million cars and trucks total in US with average age 11.4 years. 170 thousands = 0.068% of them burns annually. If we assume that average lifetime is 20 years, you have 1,36% chance that your ICE car will burn during it's lifetime. Order of magnitude less chance to burn, is just to say it humbly, actually this number is higher.

author: wraper
author_rank: Unknown
timestamp: November 25, 2018, 10:54:18 am
content: Quote from: SiliconWizard on November 25, 2018, 03:23:29 amOpen statistics PDF I linked. Also how about Ford Kuga/Escape with fire coming from engine? Not to say that if ICE cars cannot get their electric part made right, does not negate the fact that electric cars are safer.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 11:00:10 am
content: Some CO2 and foam is all you need to extinguish a fuel fire, not so for a li-ion fire. Anddd, you can drop a lit match on a buck of gas-oil and it won't burst into flames.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 25, 2018, 11:38:10 am
content: Quote from: GeorgeOfTheJungle on November 25, 2018, 11:00:10 amYou can also drop a lit match on a battery pack and it won't burst into flames.See how helpful this is?

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 11:58:40 am
content: But you can't extinguish a li-ion fire with some foam+CO2.

author: bd139
author_rank: Super Contributor
timestamp: November 25, 2018, 12:03:02 pm
content: Have you seen a car burn before? Once the plastics and tyres have gone up its game over whatever the fuel tech.Electric cars give you exit time.Let’s not forget the transport hazards of the fuel in the first place:https://youtu.be/EeZNh7VWdAo

author: 2N3055
author_rank: Super Contributor
timestamp: November 25, 2018, 12:23:21 pm
content: Quote from: bd139 on November 25, 2018, 12:03:02 pmTrust me, that wasn't only gasoline explosion.. The hole in the bridge and type of explosion point to something else in there...

author: SeanB
author_rank: Super Contributor
timestamp: November 25, 2018, 12:41:18 pm
content: I have seen a car go from running to burning pool of fire in the time it took me to get the fire brigade to answer the call. He also did not have a full tank of fuel, as the puddle of burning fuel was only around 1m at most from the vehicle.Here you should get a free pack of marshmallows and some skewers with a Ford Kuga or Escape, as there have been that many that caught fire. Joke is Fire On Road Daily as the meaning of the name. Batteries catching fire and fuel burning, not much difference in the energy output, as the rest of the vehicle is plastic that very readily burns.

author: Specmaster
author_rank: Super Contributor
timestamp: November 25, 2018, 01:02:12 pm
content: Quote from: bd139 on November 25, 2018, 12:03:02 pmExcept when the car has a fibre glass body, then its game over when only the chassis or running gear is left.The safest form of fuel in use is of course diesel but it has other side effects such as particulates which are harmful, having said that I did my apprenticeship working in a bus garage of over 100 buses and a cold morning all of those buses allocated to be the first ones out on their routes would have to be started and left idling in the garage to warm up the interiors before being driven round to the external stands for fare paying passengers to board. On those days you could not see across the garage , it is chock a block full of smoke and made your eyes sting and stream and breathing difficult. I had 8 years of that when I worked there, and on top of that every Thursday, the entire garage floor had to be washed down with caustic soda crystals and a hosepipe and electric powered floor sweeper / scrubber and that meant that every bus had to be started and moved around in order to wash the floor. The only ones exempt from being moved were those over the pits for servicing which meant a maximum of just 6 buses didn't get moved. So I worked in that heavily polluted atmosphere for 8 years and I'm still here OK (I think the dangers of diesel are grossly over exaggerated for some reason or other, might even be political).Truth is that all forms of energy carry elements of risk and that risk is proportional to the amount of energy being stored in a confined space, and that in essence is the point of a bomb, lots of energy trying to break free of its confines at the same time.

author: wraper
author_rank: Unknown
timestamp: November 25, 2018, 01:11:30 pm
content: Quote from: Specmaster on November 25, 2018, 01:02:12 pmAs if you would care how much is left if it's irreparably damaged. BTW Teslas are made from metal. X ans S use aluminium with steel reinforcement, Model 3 mostly steel.QuoteAnecdotal evidence. If 10% of workers will get cancer in next 40 years because of this and you are not among them, does not mean it was safe or there was no damage to your health. BTW it could be that parents don't have any apparent illnesses but their children might be born with deficiencies, especially brain damage.BTW you might be not so smart as you could behttps://www.nationalgeographic.com/environment/2018/09/news-air-quality-brain-cognitive-function/

author: Specmaster
author_rank: Super Contributor
timestamp: November 25, 2018, 01:36:28 pm
content: Quote from: wraper on November 25, 2018, 01:11:30 pmI was not referring to Tesla cars, but vehicles in general, many are made with not only fibreglass but also carbon fibre bodies and what is left behind when of those catches fire?Quote from: wraper on November 25, 2018, 01:11:30 pmIs it any the less true for gasoline cars?

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 25, 2018, 01:50:06 pm
content: Quote from: GeorgeOfTheJungle on November 25, 2018, 11:58:40 amLast I checked, water is what Tesla recommends for extinguishing a battery fire but doesn't work on oil fires. You might have a good argument for ethanol which can be extinguished with water, but current ethanol production leaves much to be desired...

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 01:56:30 pm
content: Gasoline is much much worse/dangerous than gas-oil.

author: Specmaster
author_rank: Super Contributor
timestamp: November 25, 2018, 02:08:55 pm
content: Quote from: GeorgeOfTheJungle on November 25, 2018, 01:56:30 pmThanks GeorgeOfTheJungle, that was what I thought, and my original statement is true, that all fuels carry risks and it's a matter of managing those risks.Nothing comes close to the sheer convenience of gasoline and gas-oil in terms of ease of replenishing the fuel on a journey, pull into a fuel station, stick a nozzle into the tank, squeeze the trigger, fill up the tank again, pay and be on your way again in a very short period of time, often less than 5 minutes, try that with electric vehicles.The nearest to that is where you use a fossil fueled engine to run a generator which drives the electric motors.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 25, 2018, 02:28:07 pm
content: Quote from: Specmaster on November 25, 2018, 02:08:55 pmYou forgot about biofuels which are an already practical approach for renewable energy in transportation. And hydrogen although fuel cells aren't quite that affordable yet.

author: Specmaster
author_rank: Super Contributor
timestamp: November 25, 2018, 02:35:22 pm
content: Quote from: NiHaoMike on November 25, 2018, 02:28:07 pmBiofuels still are not freely available in enough volume to make the switch over a viable proposition, much the same with hydrogen. If biofuels become more accessible, where do we grow food, it is reported that the world is getting to the point that it is becoming difficult to grow enough food to feed everyone.

author: bd139
author_rank: Super Contributor
timestamp: November 25, 2018, 02:38:33 pm
content: We can feed everyone fine. Just the food is in the wrong places. This has its own problems.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 25, 2018, 02:47:54 pm
content: Quote from: Specmaster on November 25, 2018, 02:35:22 pmMake biofuels from weeds that grow everywhere and there will be no competition with growing food. And the biggest problem with current food production is "factory farming" that's very inefficient if all the land required is accounted for, but that's another discussion...

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 02:56:27 pm
content: Well, yes and no, there's not many fish left in, say, the Bay of Biscay... google for example "sardine population decline". An ever bigger % of the fish we consume comes from fish farms, IIANM. That says something.

author: fsr
author_rank: Regular Contributor
timestamp: November 25, 2018, 03:40:03 pm
content: Oh, i see. Water to put out electric fires. That's unexpected, but it's what's been recommended:FirefightingUSE WATER TO FIGHT A HIGH VOLTAGE BATTERY FIRE. If the battery catches fire, is exposed to high heat, or is generating heat or gases, use large amounts of water to cool the battery. It can take approximately 3,000 gallons of water (applied directly to the battery); establish sufficient water supply.Extinguish small fires not involving the battery using typical vehicle firefighting procedures.Always use insulated tools for overhaul.Heat and flames can compromise some components, resulting in an unexpected explosion. Perform an adequate knock down before entering a hot zone.There must not be fire, smoke, or heating present in the battery for at least one hour (consider using a thermal imaging camera to measure the temperature) and the battery must be completely cooled before the vehicle can be released to second responders. Always advise second responders that there is a risk of battery re-ignition.https://www.tesla.com/sites/default/files/downloads/2016_Model_X_Emergency_Response_Sheet_en.pdfI suppose there's no way around it, as the shorted battery pack will continue to conduct and heat until it's fully discharged, so it's preferable to use water. If completely flooded, it would be like throwing every individual cell in water, right?On the other hand, gasoline is clearly not safer, as the vapours are what catch fire. Any ignition source will ignite the whole cloud of vapours, and create a big fireball, depending on conditions like the amount of wind.I once used kerosene to set some branches on fire, and i just poured like 300 ml of it, at most, and after less than a minute i thown a match from a distance. Just let me say that it was a good idea to leave some distance... I searched on flammability of this thing, and it seems to be very near that of gasoil. And better not try this on gasoline, as it's a lot more flammable. The "flash point" seems to be what determines this. The lower, the more flammable:Diesel (2-D) 52 °CKerosene 38 to 72 °CGasoline−43 °C !!!

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 03:48:46 pm
content: The problem with gasoline is that gasoline vapours aren't flammable but explosive!

author: coppice
author_rank: Super Contributor
timestamp: November 25, 2018, 03:53:02 pm
content: Quote from: GeorgeOfTheJungle on November 25, 2018, 03:48:46 pmLike most vapours (or powders like flour for that matter) gasoline is flammable or explosive depending how the vapour and air are mixed.

author: nctnico
author_rank: Super Contributor
timestamp: November 25, 2018, 03:56:36 pm
content: Quote from: Specmaster on November 25, 2018, 02:35:22 pmThe 3rd generation bio-fuels solve that problem nicely. Instead of making these from seeds these are made from the parts of the plant we don't eat. win-win (food gets cheaper and we have fuel). In the USA there are several factories up & running already so it is not a laboratory experiment. There is a lot agricultural and generic plant material available. According to the numbers of POET-DSM regarding yield per surface area it should be possible to replace fossil fuels altogether. And one of the nice things about bio-fuels is that these don't need an investment in infrastructure and the change can be made gradually by adding more bio-fuels to fossil fuels.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 04:29:41 pm
content: Quote from: coppice on November 25, 2018, 03:53:02 pmOf course. But at NTP a gasoline tank when ignited is (almost 100% sure) going to explode, unlike a diesel tank which won't.

author: Nauris
author_rank: Regular Contributor
timestamp: November 25, 2018, 04:37:34 pm
content: Quote from: fsr on November 25, 2018, 03:40:03 pmThere is that wisdom that you should only add gasoline to fire and never fire to gasoline... It is like mixing acid and water, do it the wrong way and it comes and bites you!But anyway gasoline burns so fast, it is not good for setting pile of wet branches on fire. Used motor oil or diesel is way better in my opinion.

author: coppice
author_rank: Super Contributor
timestamp: November 25, 2018, 04:45:23 pm
content: Quote from: GeorgeOfTheJungle on November 25, 2018, 04:29:41 pmI think you've watched too many action movies.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 05:00:44 pm
content: Quote from: coppice on November 25, 2018, 04:45:23 pmOr played too much with gasoline when I was a child :-) If you want to try:1) Put an inch (*) or so of gasoline into an empty 5 litres oil can2) Leave it alone for 5..10 minutes3) Drop a lit match inside...4) BOUMMMM(don't do it)Do the same with gas-oil and nothing, nada, niente.(*) Maybe an inch is too much. Two or 3 mm is enough.

author: bd139
author_rank: Super Contributor
timestamp: November 25, 2018, 05:05:26 pm
content: Csn confirm. Have done it. This always makes me laugh (works with petrol)https://youtu.be/_RNUT7b60oU

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 25, 2018, 05:46:19 pm
content: lol

author: gildasd
author_rank: Frequent Contributor
timestamp: November 25, 2018, 06:38:33 pm
content: Quote from: Mr. Scram on November 24, 2018, 12:43:07 amNot if it is a HiFog kind of system.We routinely douse the whole separator room or the thruster room to test the system, while these spaces are in operation.

author: raptor1956
author_rank: Frequent Contributor
timestamp: November 25, 2018, 07:07:22 pm
content: Quote from: nctnico on November 25, 2018, 12:10:03 amMost car designs protect the fuel tank from all but the worst collisions, but there are a few that have been frequent problems. And when the tank is ruptured you bet your ass the fuel will burn. Additionally, when a fire gets fully going then even a fuel tank that's still intact will cook off and...Yes, the proximate cause of death is usually smoke inhalation, but when the body is cooked in a 15 minute fuel accelerated fire the consequence on the body may not matter to the victim but do think of the first responders that have to deal with it.Brian

author: raptor1956
author_rank: Frequent Contributor
timestamp: November 25, 2018, 07:18:16 pm
content: As an aside I have a weird story from my childhood...I was coming home and was walking through the woods a few hundred meters from home when I came upon another kid that I did not know and had built a small fire. He had rocks around it and with some sticks he'd built a small fire like a camp fire. And then he grabbed a Mason Jar about half filled with gasoline and, with his hand over the open top, he reached the jar into the fire and stepped back. Incredibly the jar did NOT catch fire instantly and he was able to step back before a fireball about 15 meters in diameter lit up the canopy for about 5 seconds and then died down.Scary, but impressive at the same time.Brian

author: Specmaster
author_rank: Super Contributor
timestamp: November 25, 2018, 11:24:07 pm
content: Quote from: coppice on November 25, 2018, 04:45:23 pmThere was a TV program called Mythbusters that set out to see if a gasoline fuelled car would explode like they do in the movies when they crash or have a bullet fired into them, and the answer was nohttps://auto.howstuffworks.com/car-driving-safety/accidents-hazardous-conditions/can-you-blow-up-a-car-by-shooting-the-gas-tank.htm.

author: bd139
author_rank: Super Contributor
timestamp: November 25, 2018, 11:29:31 pm
content: I only have on word to say: pinto:More seriously:Also I had a Land Rover, a petrol one. It had a security feature. It leaked so much fuel that if anyone nicked it you could light the trail and blow them up

author: Specmaster
author_rank: Super Contributor
timestamp: November 26, 2018, 12:01:51 am
content: Yep the Ford Pinto as in this clip

author: fsr
author_rank: Regular Contributor
timestamp: November 26, 2018, 09:46:55 pm
content: Quote from: Specmaster on November 25, 2018, 11:24:07 pmWill blow if shoot at the gas tank? Very unlikely. Not the right amount of vapour/air mix.Will blow if gasoline vapours mixed with air find any kind of spark or ignition source? Yes.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 28, 2018, 12:37:53 am
content: Quote from: wraper on November 25, 2018, 10:31:54 amThat's only the case when we completely ignore the point of my previous post. You're comparing a small pool of modern, well maintained premium class electric vehicles with the general population of ICE cars out there, including many clunkers and less well maintained or completely unmaintained vehicles. That's hardly an apples to apples comparison.I'm not sure how that can be ignored while it's in the post quoted.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 28, 2018, 06:16:32 am
content: Quote from: Mr. Scram on November 28, 2018, 12:37:53 amExactly... A statistic says that when you quit smoking you're very likely to die in the next year. Statistically, it's true. And on that light, wraper would quickly deduce that quitting smoking is bad. Statistics are a bitch.

author: wraper
author_rank: Unknown
timestamp: November 28, 2018, 02:19:48 pm
content: Quote from: GeorgeOfTheJungle on November 28, 2018, 06:16:32 amAnd wraper would say that's a BS assumption. It might be just that people quit smoking due to medical conditions because of which they die. And please tell me how implying "correlation vs causation" debunks anything what I said?

author: nctnico
author_rank: Super Contributor
timestamp: November 28, 2018, 06:27:52 pm
content: Quote from: Mr. Scram on November 28, 2018, 12:37:53 amI fully agree. There simply isn't enough data.

author: doobedoobedo
author_rank: Regular Contributor
timestamp: November 30, 2018, 09:22:38 pm
content: Massively overcharged