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Tesla Model S achieves best safety rating of any car ever tested

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Re: Tesla Model S achieves best safety rating of any car ever tested

#171

Post by agumonkey »

jlgreco wrote: post #150
agumonkey wrote: post #137

Earlier quoted context omitted.

And I guess it's unrealistic to think of a special draining device to be brought on crash sites to exhaust the car battery. All in all, are electric vehicles more 'instable' energy wise when crashed, compared to petroleum based one ? or is it different flavours of similarly sh*tty situations ?

85KWh is a lot of energy. Back of the envelope calculations puts that at enough to boil around one metric ton of water from 25C.[1] If you wanted to rapidly drain a Tesla you would have to dump that energy somewhere. That might actually be plausible for firefighters to do[2], but I doubt the battery itself would withstand being drained anywhere near fast enough for an emergency situation. It would probably find some…

And it won't get easier since "we" want battery capacity to increase.

Re: Tesla Model S achieves best safety rating of any car ever tested

#172

Post by abalone »

lutusp wrote: post #158
abalone wrote: post #153

Earlier quoted context omitted.

Also remember we're talking about an accident scenario. There's no way emergency responders would intentionally run a high voltage circuit like that where there's a risk of short circuit in a physically compromised vehicle. They're going to be focused on containing the energy not draining it. It is fun to do back of the envelope calcs though.. You could run 50 space heaters for an hour off that sucker. Insane.

> They're going to be focused on containing the energy not draining it. In an emergency that involves extracting passengers from an electric car, the most likely outcome is that the battery will get shorted to the car's chassis, at which point the emergency links in the battery will open up, isolating the battery from the rest of the car and its passengers.

As the video explains, even when the battery has been isolated there are other components that remain electrically hazardous such as capacitors and the converter.

Also there is the possibility that the battery itself may be physically compromised in an accident, e.g. it could protrude into the cabin (it sits right under it). Not much you can do to isolate it then.

Re: Tesla Model S achieves best safety rating of any car ever tested

#173

Post by tempestn »

jacquesm wrote: post #145
Someone wrote: post #132

Earlier quoted context omitted.

The goal of a crash test is not to keep the car intact, it is to keep the driver intact. On "keep the car intact", today's cars do way more badly than those of the 1950's.

> On "keep the car intact", today's cars do way more badly than those of the 1950's. I don't think that is true. http://www.youtube.com/watch?v=joMK1WZjP7g

Great video. Pretty clear that both occupant and vehicle fared worse in the 1950s. (Although after a serious collision I doubt many people care much how the car looks.)

Re: Tesla Model S achieves best safety rating of any car ever tested

#174

Post by James_Duval »

lutusp wrote: post #155
abalone wrote: post #151

Earlier quoted context omitted.

Wish I had your crystal ball. With improvement, I was referring to the complexity of cutting someone out of a Tesla and all the no-cut zones that could electrocute passengers, emergency responders, even guys towing wrecks. You're right, there is no real safety record yet.

> With improvement, I was referring to the complexity of cutting someone out of a Tesla and all the no-cut zones that could electrocute passengers, emergency responders, even guys towing wrecks. As an electrical engineer with spacecraft experience, I can say that a car like the Model S isn't likely to electrocute anyone. While extracting someone from a wreck, emergency workers use tools like the "jaws of life", stron…

Would the tools used not be developed?

I would've assumed the production of specialised tools for electric cars would be a priority once they become popular.

Re: Tesla Model S achieves best safety rating of any car ever tested

#175

Post by James_Duval »

lostlogin wrote: post #168
sliverstorm wrote: post #112

Earlier quoted context omitted.

Err... what? If what you are trying to say, in the most roundabout way possible, is the Tesla accelerates fast- sure. But so does a top fuel dragster, and neither is a sports car. A sports car is a small, usually two seat, two door automobile designed for spirited performance and nimble handling. Sports cars may be spartan or luxurious but high maneuverability and minimum weight are requisite. -- Wikipedia (Notice it…

That's surprising to me. I have always considered a sports car to have a bit of extra power. I guess I'll have to open my mind a bit.

I suppose that would be very difficult to define.

I think sports cars have a higher power-to-weight ratio typically, but again if this was a prerequisite for a sports car then older cars would lose their sports car status over time.

Alternatively, a cheap car intended to be sporty made by a low-end manufacturer could be disqualified from being a sports car because of higher-end manufacturers throwing off the curve.

Re: Tesla Model S achieves best safety rating of any car ever tested

#176

Post by ash »

abalone wrote: post #169
lutusp wrote: post #155

Earlier quoted context omitted.

> With improvement, I was referring to the complexity of cutting someone out of a Tesla and all the no-cut zones that could electrocute passengers, emergency responders, even guys towing wrecks. As an electrical engineer with spacecraft experience, I can say that a car like the Model S isn't likely to electrocute anyone. While extracting someone from a wreck, emergency workers use tools like the "jaws of life", stron…

Hi there. Go ahead and watch this video from Tesla about how to cut someone out of a Tesla. The very first step is to cut the circuit like you say, but there are a few things you overlooked. Much of the video is concerned with instructing responders how to cut around components that may remain electrified such as the converter and capacitors which, in Tesla's own words, present a "serious hazard of shock" because "th…

Do other car manufactures provide such videos?

Re: Tesla Model S achieves best safety rating of any car ever tested

#177

Post by makomk »

ricardobeat wrote: post #130
sliverstorm wrote: post #90

Earlier quoted context omitted.

Sports cars have always made sacrifices in this regard. The first being simply that real sports cars are half the size of a modern saloon, which gives much less room for crumpling.

The fallacious argument is newer/more expensive = more secure . Every car has compromises.

Newer, heavier and far more expensive, and of course even that doesn't guarantee good safety ratings, it just makes it a lot easier to achieve.

Re: Tesla Model S achieves best safety rating of any car ever tested

#180

Post by marvin »

eru wrote: post #167
gargoiler00 wrote: post #157

Earlier quoted context omitted.

HN has a raging hard-on for tesla. It's not surprising, but I agree it's ridiculously one sided here. Personally, I hope Tesla fail, and think they will.

Why do you hope for that?

I'm guessing he shorted it at $40 like all the other smart people did.
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