
Third Tesla Fire in 6 Weeks Could Spark Federal Inquiry - alexeisadeski3
http://www.wired.com/autopia/2013/11/3rd-tesla-model-s-fire/
======
pyrocat
"Could Spark Federal Inquiry"

Where is this claim coming from? Wired? I can't find any source. To me it
seems like some writer for Wired figured they could get some clicks by
speculating.

~~~
codex
From another article:

The National Highway Traffic Safety Administration “absolutely has to
investigate” the Nov. 6 Tennessee incident, Clarence Ditlow, executive
director of the Center for Auto Safety, based in Washington, said in a phone
interview.

------
Shivetya
Face it, battery technology is not sufficiently advanced to deliver good range
without some serious trade offs. The trade off of the Tesla may prove to be
the wrong choice long term.

No one would ever suggest lining the bottom of a car with a gasoline tank,
fortunately we don't have too because the power density is so high. Hence they
can put tanks where a collision or road debris damage are least likely to
damage them.

However Tesla needs a stupendous amount of battery to get its range. Hence we
get large cars where they have chosen to isolate the entire pack at the floor
of the car. They made the choice to dispense with a central tunnel which could
hold more batteries, not use the front engine area or any trunk space.

There were to reasons for their design choice, first because of the sheer
amount of batteries needed and second because of pack swapping. I don't think
the trade off is worth it.

They can use some of the front "frunk" area to have a raised stack of
batteries where the traditional firewall is and do similar in the rear. The
could have a raised tunnel down the center line and reduce the need of having
batteries so far forward. There were many choices available but they wanted
swappable packs.

What statistic I want to see is, how many penetration events have their been
versus how many fires. How many cells have to be penetrated to create a fire?
Is there some flaw that another component is failing during these minor
accidents that is causing the fires?

~~~
codex
There are 6,000 collision related car fires in the US every year, out of 250M
vehicles. There have been 3 collision related Tesla fires out of ten thousand
vehicles in roughly six months of total drive time. That works out a 25x
higher fire risk for the Teslas.

~~~
__--__
It's nice to see actual numbers and risk rates. I had dismissed the Tesla
fires as insignificant. Your post has made me think I should take a second
look.

------
300bps
This story is unfortunate spin for two reasons. The minor reason is Wired
appears to be completely speculating when they state, "Could Spark Federal
Inquiry".

The second and really much larger reason this article is spin is that they are
painting this as a major issue without giving enough information to quantify
it. I try to quantify it in this comment and the results are the opposite of
how Wired is spinning this issue. Here's what they said:

 _While there are an average of 150,000 car fires in the U.S. each year, with
only 19,000 Model S sedans on the road, having three vehicles catch fire in
six weeks has garnered plenty of attention._

So this is comparing two data sets:

A: % of Tesla Vehicles that catch fire. Dividing 3 by 19,000 leads to a fire
incidence rate of 0.0158%.

B: % of all vehicles that catch fire. For this data set, Wired helpfully tells
you the numerator of 150,000 vehicles catch fire in the U.S. but completely
leaves out the denominator.

Without giving the complete information for data set B, it's difficult to
determine if Tesla's fire incidence rate is out of the ordinary and warrants
the speculation of, "Could Spark Federal Inquiry". So in an attempt to find
the denominator, I discovered:

[http://en.wikipedia.org/wiki/Passenger_vehicles_in_the_Unite...](http://en.wikipedia.org/wiki/Passenger_vehicles_in_the_United_States)

 _Overall, there were an estimated 254.4 million registered passenger vehicles
in the United States according to a 2007 DOT study_

Seems reasonable to use this as the denominator. If anything, since not every
registered car is regularly driven, it is likely a high estimate and therefore
understates the percentage.

But calculating it, 150,000 divided by 254,400,000 equals a fire incidence
rate of 0.059% for data set B. So the average passenger vehicle catches fire
3.73 times as often as a Tesla Model S. Now, caveats:

This is comparing an annual number (0.059%) for some other time period.
Without thinking much about it, you might believe there is weight to Wired's
assertion that this is "3 vehicle fires in 6 weeks". The Model S has been
driving on the road for much longer than 6 weeks. In fact, retail deliveries
started about a year and a half ago. While technically accurate, to frame the
data as "3 fires in 6 weeks" is misleading due to cherry picking data.

~~~
cdash
Another datapoint from Tesla blog if you don't think they are making their
numbers up is that they had a rate of 1 fire in 100 million miles driven at
the time of the first fire caused by debris. Not adding to the total miles
driven since then we are now at 1 fire in 33 million miles while the national
average is 1 fire in 20 million miles.

[http://www.teslamotors.com/blog/model-s-
fire](http://www.teslamotors.com/blog/model-s-fire)

~~~
ics
Assuming those numbers are combined highway and city miles, do you happen to
know if there is any breakdown?

~~~
cdash
Its possible this exists for all cars but I am not aware that the data has
been given for Tesla but it almost assuredly exists with their cars reporting
home all the time.

------
sanoli
This could be for any number of reasons, and also a big coincidence, and I
don't have time or the interest to read more on it, but the thing that I kept
thinking while I read the story was "why did you have to do that thing with
Boeing... you don't look too good now".

~~~
dham
Lets see the amount of fires of, lets say, the Ford Fusion in the past 6
weeks. Or maybe the amount the fires for all of Ford vehicles. It's only
because Tesla is so focused on.

This kind of reminds me how the media reports every single airplane crash. How
about report every car crash with fatalities. According to Wikipedia over
2,500 per month.

~~~
TylerE
That's just a dumb comment.

Gasoline gars don't catch on fire in non-fatal accident with any frequency

Now let's talk numbers.

Ford Fusion fleet, in the US: 1,520,000 vehicles. Tesla Model S fleet, world:
18,300. If 300 Ford Fusions caught on fire in a 6 week span I _guarantee_
NHTSA would be investigating.

~~~
sitharus
> Gasoline gars don't catch on fire in non-fatal accident with any frequency

There were 187,500 car fires in 2011 ([http://www.nfpa.org/research/fire-
statistics/the-us-fire-pro...](http://www.nfpa.org/research/fire-
statistics/the-us-fire-problem/highway-vehicle-fires)), that's just over 3600
a week, which is about 0.07% of the total cars (~254M,
[http://en.wikipedia.org/wiki/Passenger_vehicles_in_the_Unite...](http://en.wikipedia.org/wiki/Passenger_vehicles_in_the_United_States)).

3 of 18,300 Model S vehicles have caught fire. That's 0.02%.

~~~
Zimahl
Unfair comparison still. How many of those cars were old and in disrepair? How
many of them were non-fatal accidents? How many of them were due to running
over debris?

~~~
sitharus
I agree with you there, there's no breakdown on model year.

However, last year the 2013 Ford Fusion was recalled (over 89k sold) after 13
fires caused by engine overheating:
[http://usnews.rankingsandreviews.com/cars-trucks/best-
cars-b...](http://usnews.rankingsandreviews.com/cars-trucks/best-cars-
blog/2012/12/2013_Ford_Escape_Fusion_Recalled_for_Engine_Fires/)

~~~
JshWright
So you're saying the Model S should be recalled (as those are _very_ similar
failure rates)?

~~~
olegbl
Engine overheating vs. accident are very different causes for fires.

------
marcosdumay
Now that they did catch on fire, and the fire was suppressed every time, and
everything was just ok... Well, now I'm beginning to trust electrical cars.

But they still are too expensive for me.

------
TillE
The comparisons to the Leaf and Volt are meaningless if none of those vehicles
have been in similar accidents. You can't just point to numbers and imply that
a lack of reported fires means they're safer.

~~~
rgbrenner
two of the three fires were from objects hitting the underside of the car.

Nissan Leaf has sold 3x more vehicles than Tesla.

Are you saying that objects don't hit the underside of Leafs? (Perhaps they
are repelled magically?) Or that objects are somehow more attracted to the
underside of Teslas cars? Or the Leaf accidents don't count because the Leaf
owners didn't file a report that nothing happened?

~~~
vertis
I wonder whether it has something to do with the way you would drive a Tesla
vs how you would drive a Volt/Leaf.

I'm not saying that the Tesla is necessarily better performing, just that two
different types of people are the likely owners.

NB: Just pondering.

~~~
mbreese
This might just be the case, simply due to the extended range of the Tesla.
Since you can commute farther, you're more likely to be on a highway in a
Tesla. I haven't seen many Leafs on 101/280, but I see Teslas all the time.

Since these are high-energy impacts, you'd have to be traveling at highway
speed to have a damaging impact.

It might be more interesting to compare how a similar car style would behave
(think high performance sedans).

------
Pitarou
There may be a problem. We can consider the Tesla as a car body bolted on top
of a huge battery. Collisions with road debris seem to be sufficient to pierce
the battery's armour and start a fire.

This isn't disastrous. Problems like this routinely emerge with new designs.
And at least the flammable materials stay in one place (unlike a gasoline
engine). But still, a fire's a fire, and I'm sure Tesla's engineers are
working overtime trying to figure out a solution.

~~~
bsdetector
> and I'm sure Tesla's engineers are working overtime trying to figure out a
> solution.

What could the solution possibly be? Puncture the battery and it catches fire,
and the battery covers almost the entire bottom of the car. Practically
speaking there's only so much steel you can put on the bottom of the car.

It seems that Model S spreading the battery across the bottom of the car may
simply be a defective design.

~~~
Pitarou
Use your imagination!

The conditions that cause the fires seem to be narrow and well-defined enough
that a clever workaround is possible. Maybe add an extra layer of sacrificial
armour? Or move some cells away from the vulnerable region.

------
scythe
Alright, let's do the math.

150,000 car fires per year / 52 weeks is 2880 fires per week. There are
135900000[1] vehicles in the US, which gives 21.2 fires per million-vehicles
week. With 19000 Teslas on the road and three fires in six weeks we have 0.5
(fires / week) / 0.019 (million vehicles) = 26.3 fires per million-vehicles
week. So even if this _is_ typical for the Model S (and it doesn't seem to
be), the cars aren't much more likely to catch fire than ordinary cars. Also,
I haven't accounted for the fact that the Model S's probably get driven more
than your average passenger car, both due to low per-mile costs and the fact
that they're more likely to be new and thus valued by their owners. Taking
this into account would probably bring the Model S's fire-rate below gas cars
again.

[1]:
[http://www.wolframalpha.com/input/?i=number+of+cars+in+us](http://www.wolframalpha.com/input/?i=number+of+cars+in+us)

~~~
rgbrenner
The average car is 11.4 years old [0].. the average Tesla is still practically
brand new. Not really an apples-to-apples comparison.

[http://www.autonews.com/article/20130806/RETAIL/130809922#](http://www.autonews.com/article/20130806/RETAIL/130809922#)

~~~
justin66
The trouble is that there are a lot of ways to slice the data, and just not a
lot of data yet.

For example, I wonder what happens when you group the Tesla S in with cars
that can do the quarter mile in under 13 seconds...
[http://www.wreckedexotics.com/](http://www.wreckedexotics.com/)

------
6ren
They are having more accidents than other electric cars (3 vs 0), and it
certainly seems that having four times as much battery power, and lining the
base with them, is the problem.

There's nice spin you could put on this, which is likely true: people who have
Teslas drive them more, because they are fun, cool, excellent - and have 4
times the range and power. Secondly, with more power, you will drive faster,
hence greater likelihood of accident, and of greater severity.

But Tesla's gotta fix this. For PR reasons, and to be making a great car.
There's always going to be unforeseen problems with new tech, the only issue
is how you handle it.

It's a bit of a shame though: low slung batteries give low center of gravity
and great handling and stability. Thicker armour adds unnecessary weight.
Perhaps armour that deflects rather than stops? Perhaps a different failure
mode for the batteries; built-in extinguishers? (i.e. the issue is fire, not
car damage. Ideally, solve both).

~~~
alexeisadeski3
> Perhaps a different failure mode for the batteries; built-in extinguishers?

I hesitate to say 'it's not possible', but:

-Until a new battery formula becomes viable, we're pretty much stuck with batteries that light up when abused. Hopefully new formulas come online soon, but who knows wether or not they'll actually be safer.

-Chemical fires are pretty tough to extinguish via conventional means.

------
robotcookies
Apparently the battery pack in a Tesla has liquid cooling so it probably gets
fairly hot. In a gas car, the liquid cooling is for the engine and if it
fails, the engine overheats and stops. But imagine if the gas tank itself got
hot when running and needed to be actively cooled. That's basically where the
Tesla is at. A failed cooling system means the energy source overheats (and
not the motor/engine).

I'm not a car expert but I imagine it's hard to protect all the pipes that are
carrying the liquid. And that may be why these fires are starting... some
puncture causes the liquid to release. Just a theory.

~~~
Dylan16807
I would assume a car that has been involved in a crash would stop moving, and
not need that cooling any more. Even if there _weren 't_ failsafe systems to
shut things off.

There's only so much you can do with a punctured lithium ion.

~~~
robotcookies
What do you mean failsafe? That the batteries would shut down? My
understanding is that in two of the incidents the drivers were able to
continue driving until they found a safe place to get off. I think there would
be a safety issue if the car completely shut off power on a freeway due to the
cooling system failing.

~~~
Dylan16807
Yes, that the batteries would shut down if they were overheating from use.
It's certainly safer than the alternative.

------
codex
A quick back of the envelope calculation shows that, at this rate, the Tesla
Model S is roughly 25x more likely to suffer a fire after a collision than a
non-Tesla.

While gas powered cars must, out of necessity, carry a tank of flammable
liquid around, which is fairly unsafe, the gas tank is not in the front of the
car. No other electric car manufacturer puts their batteries so far forward
under the hood, either. The Tesla also has very low road clearance.

~~~
olegbl
Such small numbers make terrible statistics. For instance, I could say that
"the Tesla Model S is infinitely times less likely than a non-Tesla to suffer
a fire which leads to a death." 0 for Tesla, X > 0 for others.

------
TallboyOne
I mean, tbh I really don't care - I still want one. I feel like this is the
same as saying people get struck by lightening.

------
fleitz
In other news cars tend to burn when their fuel tanks are punctured after
colliding with large objects at high speed.

------
codex
It occurs to me that these fires do not pose a direct risk to the occupants,
but do carry indirect costs:

\- Firefighters will take longer to rescue injured from the passenger
compartment

\- The fire can possibly ignite spilled gas from other cars in a multi-car
accident

\- Insurance rates will be higher, as a collision is much more likely to total
the car

------
johnpolacek
You can't make an omelette without burning a few cars.

------
bane
I was surprised with how many Leafs have sold. I rarely see one, but I see a
Tesla at least twice a week these days.

~~~
dangrossman
I've yet to see any Tesla car on the road. I _have_ seen the Leaf and Volt. I
have a feeling they have different geographical distributions.

~~~
photorized
I am seeing Teslas daily in CT. Leaf or Volt - not so much.

~~~
Anechoic
Where in CT? I spend a fair amount of time in the Hartford area and have never
seen one.

