Tesla Model S Caught Fire While Parked and Unplugged

cartechboy writes "The safety headlines involving the Tesla Model S were a mixed bag last year. The good news was the Model S received a top safety rating, but the bad news came with three of those electric cars catching fire after receiving damage to the battery packs. (Though coverage of the latter was disproportionate to the coverage of fires in other types of vehicle.) Now another Tesla Model S has caught fire, but this time the car was parked and unplugged. The fire happened earlier this morning in the owner's garage in Toronto, Ontario. At this time no one knows what sparked the fire, but we do know the vehicle was only about four months old. Again, it wasn't plugged into a charging station, and it wasn't turned on. With no one near it. Interestingly, the battery on this particular Model S was unscathed by the fire. In fact, the Toronto fire department says the fire didn't originate in the battery, the charging system, the adapter or electrical receptacle since all of those components weren't touched by the fire. So, how did this Tesla fire happen, and will this blow up into a larger issue for the new automaker?"

Comments

Not from the car?

[Dthief]

Why are they assuming it was started by the car?

"In fact, the Toronto fire department says the fire didn't originate in the battery, the charging system, the adapter or electrical receptacle since all of those components weren't touched by the fire"

maybe the fire was cause by something in the garage adjacent to the car?

Re:Not from the car?

[interkin3tic]

Clearly GM set the fire intentionally and then paid off the fire department to say it was the Tesla, but the fire department failed to make it convincing! WAKE UP SHEEPLE! There's a vast incompetent conspiracy going on!

Same way as other cars

[Michalson]

Normal gas cars catch fire every day just sitting in peoples driveways or driving along. It's usually a short in the 12V (regular car battery) system related to one of the electronic accessories. It can happen because water gets in and corrodes a contact (like the electric windows) or heat from a nearby item like a headlamp wears down the insulation or other wear and tear that cars are subjected too. In some cases it is identified as an engineering fault rather then a unique occurance in which case a recall occurs. If you go back 3 years you can probably find at least one recall for each of the major manufacturers to fix an electrical fault that 'could lead to a fire'.

Having some basic knowledge about car fires makes it clear just how much Tesla fires are about media hype.

Re:Same way as other cars

[Todd Knarr]

Well, if I look at the number of cars in the US (254 million or so) vs. number of car fires per year (152 thousand or so on average), and then look at the number of Telsas sold vs. number of Teslas involved in car fires, the rate for Teslas is a third to a quarter that of gasoline-powered cars. So yes, if a gasoline-powered model had the same fire rates as Teslas and there was detailed coverage of every single fire it was involved in I'd make an accusation of media hype, how else would you explain that focus accompanied by a lack of coverage of models that catch fire 3-4x as often?

Tesla not involved [Re:Not from the car?]

[Geoffrey.landis]

If the fire "didn't originate in the battery, the charging system, the adapter or electrical receptacle," then the fact that the car was a Tesla is pretty much irrelevant, since those are the things that make a Tesla distinct from any other kind of car. So, this seems to have been a fire in which the car parked in the garage happened to be a Tesla, rather than something specifically Tesla related.

Re:Tesla not involved [Re:Not from the car?]

[bluefoxlucid]

There's one motor, a direct drive linkage (no transmission), and differentials. Hub motors require all kinds of computer control, with associated high chances of fault that could much more easily lead to loss of control or efficiency. Hub motor efficiency is kind of like video poker: perfect play for 3 years straight will net you a profit, absolutely, no question you will beat the casino; the profit is small, and a single small mistake will set you back about 85 years. It only makes sense in a motorcycle, where you have one rear wheel hub motor.

Re:Tesla not involved [Re:Not from the car?]

[Immerman]

I suspect it's mostly synchronization issues. Trying to get two independent motors turning at exactly the same speed is likely a major challenge, and if the speeds are even slightly different then the car will pull toward the slower one. A differential meanwhile is a relatively simple and well-understood piece of technology that does the same job (uniform wheel power with slippage compensation) more simply.

Plus the cooling system is no doubt much simpler with only a single motor that's not surrounded by a big spinning wheel.

Re:Tesla not involved [Re:Not from the car?]

[bluefoxlucid]

In a mechanical system, you can have things like viscous couplers or torsion differentials. The wheels will spin at the same speed, but if one encounters less resistance then more power will move to the others. A single power unit supplies power input, which is then distributed based on the laws of physics as applied to a complex mechanical system. Gears and metal poles are lossy due to heat from flexing, compressing metal; viscous couplings are obviously more lossy because they're non-solid and thus the working fluid is experiencing far more deformation than metal.

In a hub layout, all those inefficiencies go away. Computers perfectly apply the correct amount of torque at the correct rotational speed directly to each wheel. For a given RPM, the motor will simply spin at no torque unless there is resistance, at which point it will draw more power to retain spin speed.

Unless... your calculations are slightly wrong. And the motors have loss by heat--which they do. And the computer has to calculate when to back off power to one free-spinning motor which is now heating up and spinning the wheel too god damn fast, but only after taking a sample.

Hub motor efficiency gains aren't ungodly massive; they're small, and they require perfect operation. They also require additional (powered) sensors and computer number crunching, rather than passive mechanical systems which simply cannot function in any manner besides "distribute power correctly" or "fail completely because the system is broken". Drifting sensors, poor sampling, and just the need to get enough of a sample to make a statistically significant analysis and adjust power output per wheel all rob hub motor systems of their theoretical maximum efficiency. The first of these is of particular practical importance: it's extremely easy for this system to be out of spec and inefficient without the end user knowing or caring. The rest are engineering challenges.

All of these potential failures are multiplied by the number of hub-powered wheels. An entire drive train system--a hub motor, its connection to the wheel, sensors, power connectors, regenerative braking mechanisms, and so on--must be duplicated four times to get all-wheel drive. With a single power unit in a mechanical system, you only need to build one drive train, which is simpler and only needs to be incrementally improved in very direct and simple ways. No improving computer code for the average case while trading off the better case; no attempting to get sensors to get more precise data, then trying to factor that improvement into the rest of the control system. You use better alloys, better machined gears, you use what you learn from further research to tweak the design so that it couples and transfers power more effectively and reacts more quickly and immediately to slippage.

The big driver for hub motor vehicles is all the things you can do in theory. Modern traction control and ESC applies braking force to individual wheels, whereas you could just back off the hub motor... or apply braking force by the regenerative brake. But that begs the question: aren't you using the same computer control programs for regenerative brake applied traction control as you are for hub motor regenerative brake traction control? And then of course those benefits essentially come down to the corner case of driving in terrible conditions, which is inefficient as hell anyway--and your efficiency gains are minimal.

Lots of funny theory, lots of "with X we can Y", as it has always been. One of the big pushes with Firewire was that we were going to have revolutionized home entertainment: you would have abstract equipment with IEEE1394 ports, plug a speaker into the VCR, plug another into the TV, subwoofer into a receiver deck at the back of the room daisy chained to the DVD player, and daisy chain rear room speakers off that, and all these devices would find each other through these arbitrary connections and unify themselves as your home theater. That was being heavily advertised in home theater shops for a while, but it never happened. All these things you should be able to do with your iPad never materialized. The XO Laptop hasn't met its potential yet--it has revolutionized nothing. Same with hub motors.

Re:Tesla not involved [Re:Not from the car?]

[Anonymous Coward]

They have one motor per axle, which eliminates the need for perfect synchronization (if the axles run at slightly different speeds, that's just a loss of power, not control).
They also run on rails, so smaller de-synch issues that would cause a car not to go straight or have difficulties cornering result in nothing more than slightly more noise for a locomotive.

Re:Home owner declines Tesla assitance?

[qparadox]

http://business.financialpost.... When Tesla offers to pay the owner of the car for the damages to his home, the guy declines. Now, call me stupid, but that's a little weird no?

Its not really that unusual. He likely has fire insurance that will cover the damage to his house and would rather deal with the insurance company than directly with Tesla. The insurance company can send the bill to Tesla and deal with the hassle, administrative details and lawyers, rather than the car owner.

Re:My Advice to Tesla

[BasilBrush]

"Loudmouth investor"? Do you mean the Tesla CEO, Elon Musk? CEOs are supposed to speak for their company.

You seem to have an axe to grind.