Tesla Model S, Third Fire

[nctnico]

Today I had to waste some time while my wife was shopping and I came across the Tesla store in Amsterdam. They had a Model-S on display and a chassis. The model-S isn't a very big car though. The 2 children's seats in the booth are an interesting option but I'm not sure I would put my kids in there. The booth is usually one of the less well protected parts of a car. OTOH smashing your car into the back of a Model-S is a bad idea. The big engines and the diff+gearbox are directly behind the rear bumper.

Anyway, I also took a look underneath the chassis. As I already suspected the batteries are the lowest part of the car and not the beam behind the bumper. Anything which passes underneath that beam can go on a rampage when it gets to the battery pack.

[tom66]

The rear is the safest place of all places in a car, for a number of reasons. Most rear-ends are at lower speeds compared to front-end collisions, and the rear is a lot easier to reinforce having no engine and stuff in the front end (though this is less important in the Model S' case.) Also, the seats are rear facing. This is the best position for children in a crash as the risk of neck injury is reduced, and why child seats should be reverse mounted where practical.

The one thing I do wonder about is if the rear window could pose a significant hazard in a crash, given it's a lot more forward and likely to shatter. Small children might be injured by such pieces.

Apparently the reason rear seats are a factory only option (not something added afterwards) is there is extra reinforcement added to the bumper for those versions.

The drivetrain is lightweight! It apparently weighs around 300 lb. Try and find an engine for a 400hp car that weighs that little. The motor is about the size of the watermelon, the inverter too. Single-speed gearbox in between, very nice, small package.

[nctnico]

I've seen and touched the motor today (they had one on display which was cut open) and if you say the motor is the size of a watermelon then your watermelons are HUGE! Crashing your car into a 150kg / 300lb piece of metal isn't going to be pleasant. It is much better to have a car where the rear deforms a lot in a crash. It will make the forward accelleration less so reducing the chances of neck injuries. A car has to deform in a crash in order to reduce the G forces on the occupants. Just look at formula 1 cars crashing. All the bits and pieces flying around are designed to break in order to absorb the energy from the crash to save the driver.

And I don't understand your reasoning about rear end collisions being less severe. Someone has to crash the front of their car into the rear end of your car 

edit: the drivetrain may be light but the batteries are not. Apples and oranges...

[zapta]

Apropos Teslas, the other day I was waiting in a red light and saw a Tesla almost loosing it.  Don't know if it was the driving skills or the traction control that saved it:

https://www.dropbox.com/s/jajwzp01kxzkbfx/tesla_sliding.mp4

[nctnico]

Letting it skid a little isn't a problem. I do the same when it is a bit slippery in the winter.

[tom66]

Size of a watermelon is an approximation, of course, but for a 416hp motor (same motor used in all models) it's small, well, compared to a 416hp ICE.  I do like the packaging all on the rear suspension too, and the floor mounted battery pack.  Great low COG and weight distribution. Also the powertrain is lightweight, compared to the heavy battery.

Most collisions into other cars are at lower speeds (it's a lot easier to brake when you're expecting a car, versus, say a wall or tree); this is why NHTSA tests into relatively non-deformable barriers[1], as these are the most severe, and almost invariably into the front of a vehicle. You'll notice side crashes are done into poles[2], or into vehicle simulators[3] (the surface of which deforms.) Again, because these are the most common. Crashes at very high speed into the rear of other vehicles is rare, but even in that case, the rear is the safest place to be of any part of a car.

Having the skate board design battery at the floor of the vehicle is ideal because it minimises the flexing of the vehicle in side or pole impacts. It however does pose a risk to other vehicles. The car is deceptively heavy. It can be deadly when hitting older vehicles. No one has died in a Tesla but several cars have been very badly damaged by impacts and at least two have died in other cars.

Personally I don't think the fire problem is anything to get worked over. It's barely a problem. If an ICE were to sustain such damage, it would be written off or subjected to extremely expensive repairs -- that's if, of course, the driver was OK given the floor of most vehicles doesn't benefit from a 3 inch tray of solid battery cells. The Tesla gave over 2 minutes warning before the fault became noticeable (smoke) and ~4 minutes before actual fire occurred.

[1]:
[2]:
[3]:

[free_electron]

As EEVblog readers the key question to ask yourself is : is my car compatible with EEVblog ?

Anything else is irrelevant.

The TESLA is compatible ! See proof below

[notsob]

WOW - I can see that smile from this side of the pacific, congrats Vincent.

[dr.diesel]

is my car compatible with EEVblog ?

Penguin inside, awesome!

[nctnico]

As EEVblog readers the key question to ask yourself is : is my car compatible with EEVblog ?

Anything else is irrelevant.

The TESLA is compatible ! See proof below

Cool! You bought a tablet on wheels with a roof! 
Now get a wrench and screwdriver for a teardown!

[free_electron]

is my car compatible with EEVblog ?

Penguin inside, awesome!

not exactly.

It is a heavily modified linux kernel. In the sense that anything that is not relevant has been stripped out. also the way it boots is different. It is a static linked setup. There is no dynamic loading of modules. So even if you would succeed to load other executable files on the drive the system cannot load them to run them. Anything thrown on the user drive is treated as 'data', even it it is a perfectly fine executable file. The executable portion can only be changed by tesla. as a user you have no access. there is even no 'userland'.

the linux portion is limited to the display only. It only does visualisation. the real 'processors' running the car are separate. the two screens can read information and , pressing a button on touchscreen , request to a cpu to turn on the lights for example. it is not the linux machine that has control over the physical light.

you can restart both computer ( the dashboard is a separate computer running on a tegra 2 processor. the big center console is a tegra 3 based device )
hold both top buttons on the steering wheel for 5 seconds and the dashboard reboots. hold both bottom buttons 5 seconds and the center console reboots.
you can do this while driving. it has no impact on the operation of the car.

the steering wheel interfaces to its own control processor and this guy can yank the reset lines of either dashboard or center console.
when those guys reboot the simply tap into the CAN bus running the car , pick off the data flying by there anyway and visualise it.
from what i have heard is that both panels can only 'listen' to the traffic. they can not even request a packet.

so in a sense the driving systems are completely autonomous. the displays are only for visualisation and non essential things like audio and navigation. if they go belly up it doesn't matter.

They use special cpu's with a dual core. The second core runs independent software ( the instruction set is different between core 1 and 2 ). core 2 monitors execution of core 1 program. if it steps out of line core 2 will pull the plug and force the main program to behave. Someone yesterday mentioned they were Qoriva (i don't know if i wrote this right) processors. i need to look it up. never heard of it.

[free_electron]

As EEVblog readers the key question to ask yourself is : is my car compatible with EEVblog ?

Anything else is irrelevant.

The TESLA is compatible ! See proof below

Cool! You bought a tablet on wheels with a roof! 

my tablet is not only rainproof, it also comes with comfortable heated seats and i can go get something to eat with it !

[NiHaoMike]

when those guys reboot the simply tap into the CAN bus running the car , pick off the data flying by there anyway and visualise it.
from what i have heard is that both panels can only 'listen' to the traffic. they can not even request a packet.

I haven't driven a Tesla but if it works like other EVs (does it?), how would the touchscreen control the charging and whatnot?

For that matter, does it support a protocol for changing the charge rate in real time? A good use case I can think of is when charging from an alternative energy system (which I presume would be very popular with Tesla owners), you could have a Raspberry Pi in the (home) power system increasing and decreasing the charge rate according to generation.

[tom66]

If you use J1772 adapter, you can feed a simple PWM signal into the pilot pin, which is isolated from the mains side. 0%-9.9% is off, 10%-96% is 6-80A, and 96%+ puts it into a special mode of some sort (not sure what, maybe switches it to a data protocol.) Easy enough to do from a basic MCU. And compatible with loads of EVs, like Nissan Leaf and GM Volt too.

@free, maybe "Qorivva" by Freescale? They are very big in the automotive world. However much of the Tesla "under the frunk" or torn down (it's a fascinating vehicle) I have seen the one thing I cannot see much of is the typical multitude of "engine computers".  I suspect Tesla will have one box for the majority of the vehicle control. Things like the ABS are probably supplied by Bosch or another automotive supplier, but the traction control, for example, is definitely Tesla-born. Is it all in one motor control unit? I wonder what's involved in the software for such a unit.

[amyk]

Is that whole dashboard a touchscreen? Doesn't seem all that great of an idea in a car when you're driving and trying to adjust things...

[free_electron]

The whole dash oard is a mssive touchscreen, yes. The only physical buttons in the tesla are
-the 4 blinker warning button
-abutton to open glove compartment
-4 buttons for windows driver side
-1 window lock button driver side
-three mirror buttons driver side , two select left or right mirror, the third retracts mirrors
-a 4 way mirror pan/tilt paddle driver side
- 3 buttons, one passenger side, one rear left and one rear right to control those windows
- an illuminated button inside the frunk to unlock it should you be inside .. Duh!
- a button on the tailgate to open
- a button on the tailgate inside to close and set opening height limit

The control levers are limited to
Left/right turn
Park/forward/reverse/neutral
Cruise on off /faster/slower/resume/set
Pull to wash windscreen.

There is no control for headlights, windscreen wipers , speed of windscreen wipers , fog lights. You dont need that. The computer knows

The abs system is tesla made. As most of the braking happens during regeneration the motor can detect a wheel stall : the rpm of the rotor collapses immediately. So they lift regen to get them running again. Essentially the torque controller works both ways, during acceleration and deceleration.

You barely use the traditional brake pedal. Only for the last meter , and to hold the car in position. The regenerative braking controlled by throttle works perfect. Combined with parking radar it even slows down should the driver not react.
When parking in my garage the radar stops the car at a fixed distance. It will refuse to approach further , so i assume this also works on the road. It really 'stops'

The real car control computer sits under the armrest for the driver and passenger (where the usb ports are). Also the graphical computers sit there. There is simply an lvds link feeding the display panels. The reason is software updates. They do not want to send all the different firmware modules to the far corners of the car. It is all contained in one box.

There are  separate, non critical processors. The nose has its own driving the lights and local actuators/sensors like radar, wheel pressure sensors, windshield fluid level and wiper motor, hood release etc.

The tail has the same for light, hatch release etc

The battery pack has like 20 cpu's inside. The battery is split in 16 modules each having its own charging and balancing processor. They communicate with the battery controller and charge controller.
Then there is the main charge module outside the battery. This takes incoming power and converts it up to the required 380 to 400 volt for the battery.

The propulsion system inverter also has its own computer.

What i am saying here above is public knowledge. Teslamotors forum and teslamotorsclub forum has all that info. Some guy already figured out how to open the charge port. He uses a simple pic processor to transmit a burst at 458 MHz, someone else reverse engineered the REST api and made a google glass app for the tesla that can interface with the car.

During the factory tour (you need to sign an NDA before entering, and no picture taking is allowed) we got to see cars in various states of assembly. One i took a long hard look at is the (low voltage) wiring harness.
There is virtually no wiring in this car. A big connector leaves the area between driver and passenger seat, which seems to confirm the central computer box there. It fans out , three bundles to rear, one bundle left and one right (i am assuming doors: controls plus speakers) , two bundles to front, three bundles to cockpit.
Each end then splits into small 'tails' like two wires for speaker , another tail with three wires for something else, ay e the side airbag etc.

But main bundles are all small wires accompanied by what looks like a low voltage feed and return.
They do not seem to be using the chassis as ground return !probably because the entire car is aluminum.

I have seen cable harnesses for traditional cars and they are much much larger.

I think tesla uses one or more can busses to the local units. The other individual wires are probably simple things like two speaker wires , a power and a ground and the two can lines. The airbags probly have their own four wires. Most of the bundles are linke only the thickness of two pencils.

I suspect they dont even splice anything inside a cable bundle. It is probably all point to point between an end unit (cpu module, airbag module or a speaker) and the central controller.

This thing is really radically different from anything else.

I am still amazed at how simplified the operation is.

Walk to the car , the car wakes up when it senses me 3 meters away and it extends the door handles , unfolds the mirrors , music is playing, displays are on. I open door, sit down close door. Press brake pedal and click it forward or reverse and drive.
I dont need a brake pedal, i dont need to turn on headlights, i dont need to control wipers , no gears to change. All i do is control speed with 1 pedal , direction with steering wheel and use the blinkers .
There is nothing else to do.
When i am done i click it in park , get out , close the door and walk away. When the car can no longer sense me it retracts mirrors, doorhandles, and goes to sleep.

I dont need to pull the handbrake (there is none) i dont need to remove a key , push the remote to lock the car , remeber to turn off lights .

Walk to car ,get in, click forward/ reverse and use steering wheel and throttle pedal. Click park, get out, Walk away
Thats it.
Think about it. Why do cars still need all these control levers and buttons like they did 50 or 100 years ago? We all grew up with cartoons like the jetsons and dick tracy, we all seen 70's scifi movies that showed us stuff in 2020.. How come we arent't there yet ? The tesla is the only machine that lives up to that 'futuristic promise'

Last night as i parked the car there was a little popup telling me the car would do a software update overnight.

What happened? A few days a go there was a fire in a garage in san diego. The firemen said the car charger caught fire. The car had no damage , no damage to charge cable either. Only the wall connector had melted and burned.
Tesla dumped the telemetry of the car. They detected voltage fluctuations. Further investigation revealed the electrician had used too thin a wire for the outlet. The wire inside the wall had overheated , melted and started arking. For some reason the mains breaker had not tripped.

Us breakers do not trip immediately. If wire insulation carbonises this may not immediately trip. It does cause voltage sagging.

Well, the new software now has a detection algorithm. If the incoming voltsge starts fluctuating wildly, like telemetry showed in this case, the charger will reduce current draw 25%. If it keeps fluctuating it will reduce another 25% and so on.

So now the car can even detect faulty or flaky house wiring and will lrotect yor house as well. How's that ? I think it is brilliant !

[dr.diesel]

Tesla really appears to have their shit together.  Funny how a start up beat the big dogs with their massive R&D resources to a refined product.

[NiHaoMike]

You barely use the traditional brake pedal. Only for the last meter , and to hold the car in position. The regenerative braking controlled by throttle works perfect.

The Prius has something similar but most drivers seem to hate it. How has Tesla done it better?

[tom66]

Are you sure about there just being an LVDS for the panels? There's a picture showing a removed touchscreen:
http://media.ed.edmunds-media.com/tesla/model-s/2013/lt/2013_tesla_model-s_det_lt_226132_600.jpg

which clearly shows fans and heatsinks, there must be some processor there, quite a beefy one it would seem!

The HVAC system of the Tesla is also very clever.

It has two coolant loops, which can be combined into a single loop in cold climates (series mode) or kept separate (parallel mode). The battery coolant is warmed up when it is cold and also used to heat the cabin. If you use the A/C it won't waste the extra cooling power and will use that to cool the battery. Similarly when you do hard acceleration and produce heat in the battery/motor/inverter/DC-DC that heat is recycled to heat the cabin.

It's extremely complicated under the frunk compared to what an ICE uses.

It surprises me of all things Tesla still has a lead acid for the 12V system... it's the one thing that's caused tons of issues... they should consider a NiMH or LiFEPO4 backup battery.

[M. András]

how is the security/anti theft systems? is it controlled by the key too? i wonder how long will it take to the luxury car thiefs to figure it the authentication etc

[free_electron]

The big dogs have grown so fat and lazy and uninspired that it needs a little yapper to bite their ankles.
All the new car models do is add two cupholders for the next model year. Really ? That is your level of innovation ? Please roll over and croak . Ok ?

I took delivery of my car at 4pm on sunday. There were 9 other cars scheduled for the same time that day.
I asked how many they delivered that day (these are customers coming to the factory to get their car in one day, so it does not include people picking it up at tesla stores or getting home delivery) the guy said ' about 80... Its a slow day today...

You mean there are 80 of these cars delivered on a sunday ? Cars costing 100k$ each ?
Tell that to your car dealer.... Here is a little company that, 18 months ago did not have a car (the roadster was obsolete and the model s did not ship until june last year. 12+6 months) and they deliver 80 cars a day ? Watch what happens. That sales guy will probably get on a chair, nail the end of the tie he is wearing to the rafters and jump off the chair.

Rest assured that the other car makers are getting nervous and are eyeballing tesla...

Mercedes has taken a 21% stake in tesla... Merced is releasing the B-class all electric in March. Tesla drivetrain. Toyota has the rav-4 and soon the Camry with tesla drive train.

That is the sign on the wall. Here you have the largest car maker and the largest luxury car maker lining up behind the newcomer..... Amd you know how germans and japanese traditionally are... If it doesn't come fro. Their country it can not be good... Yet they buy this technology from Silicon valley ...

Te big boss of GM is on record for the following statement:
Here i am, ceo of a car maker with over 100 years legacy, employing 30.000 engineers. They all told me lithium ion is at least 10 years away. Can someone explain me how a 70 people startup in silicon valley, with no prior car experience is selling such cars?

You have to grant tesla the fact that they have balls of steel. They are not afraid.

There are two other, true, stories that prove that.
Elon had the nerve to walk up to Mr Toyoda, CEO of toyota , hand him the keys to a roadster and take it for a drive. Three days later Toyota gave Tesla a 40 million dollar checque with the request to use the money to buy the closed nummi factory and rehire the employees and make it the tesla factory.

This factory is 5.5million square feet, has its own train station and today employs 2100 people assembling cars that 'were impossible to make, with battery technology at least 10 years away, nobody would want because we all know electric means slow and small range, and would be too expensive'.
Fact:  Tesla sold more Model-S cars this year than all models of Porche combined. Stick that in you tailpipe. You caneven add all AUDI A8 to that number.

Anecdote two:
Tesla procures some parts from mercedes like the steering wheel. The germans wanted to visit this little startup. Elon sent JB Straubel, head of engineering , to mexico to buy a smart. Smart was not available i. The US yet.
They worked 6 weeks day and night, sleeping in the office building, converting that smart car to the electric motor and battery of their roadster.

When the mercedes people arrived they were  shown the smart car. The germans were wondering : how did these guys get their hands on a smart ? We dont sell em in the US. Tesla explained they bought it, cash, in mexico and spent the ladt 6 weeks converting it to electric. The germans couldn't believe this. They were shown the dated invoice.

One of the big bosses of Mercedes took seat in the smart, floored it and shot out of the hangar like a bullet. He disappeared for at least 15 minutes. Everybody was getting worried. When he finally came back and got out , this stoic german had a huge grin on his face , was laughing and dancing like a little kid.
Two weeks later Mercedes took a 14% stake i Tesla. They have upped that since...

Here is the thing: we wanna build an electric car. What do we need?

We need battery technology, silicon valley has plenty of that.
Motor control... thats electronics. Silicon valley can do that.
We need software .. Silicon valley can do that
A user interface.. Lets get some guys from apple... in silicon valley
It needs to be aerodynamic... Our boss owns SpaceX they know all about aerodynamics, they are fucking rocket engineers!
We want fancy stores... Lets get the guy that design the apple store concept.
We need seed money... Our boss invented Paypal and sold that for a hefty sum... And there is plenty of venture capital in silicon valley...

Add that up ... And tou know what time it is...

[free_electron]

You barely use the traditional brake pedal. Only for the last meter , and to hold the car in position. The regenerative braking controlled by throttle works perfect.

The Prius has something similar but most drivers seem to hate it. How has Tesla done it better?

I do t k ow how the prius system feels. The tesla works very well. Keep in mind the prius is a dual drive . The tesla is full electric ,so the mechanics probsbly get in the way with the prius.... I do t k ow.
All i can tell ks that the tesla brakes proportionally with how fast you remove your foot. Its like a computer mouse. Move slow for precision, move fast for speed.
It takes 5 minutes to get used to.

[free_electron]

Are you sure about there just being an LVDS for the panels? There's a picture showing a removed touchscreen:
http://media.ed.edmunds-media.com/tesla/model-s/2013/lt/2013_tesla_model-s_det_lt_226132_600.jpg

which clearly shows fans and heatsinks, there must be some processor there, quite a beefy one it would seem!

The HVAC system of the Tesla is also very clever.

It has two coolant loops, which can be combined into a single loop in cold climates (series mode) or kept separate (parallel mode). The battery coolant is warmed up when it is cold and also used to heat the cabin. If you use the A/C it won't waste the extra cooling power and will use that to cool the battery. Similarly when you do hard acceleration and produce heat in the battery that heat is recycled to heat the cabin.

It's extremely complicated under the frunk compared to what an ICE uses.

Hmm. Maybe the tegra processors are in there. It would make sense. The central computer under the armrest may be the actual driving computers. The touchpandl has the visualisation computers.

Would make sense. Again. Part of it is speculation on my end. I looked at the wiring harness laying in the car.. Very few wires. Big connector , lots of pins where the armrests are. Smaller one where the dashboard would be. Maybe that one is simply a bunch of can busses.

The hvac in tesla is not only for passengers. They actively heat and or cool the battery, motor, inverter and chargers. It was charging overnight and i heard several times something that sounded like a pump or compressor kick in (i did some work in the lab next to the car) the compressor sound lasts like 2 minutes followed by a different sound for liek another 2 minutes. Kind of like an aquarium pump type sound. They are probably refrigerating the battery coolant and pumping it around for a while. This happens like once an hour. I heard it three times between roughly 7pm and 11pm when i went to bed.

When plugged to the supercharger you hear this more often.

I know that in vety cold weather they preheat the battery before charging. The charge connector blinks blue then.
White is waiting for connection, blue is conditioning battery for charge
Pulsing green is charging, solid green is 'full'

[dr.diesel]

Hmm. Maybe the tegra processors are in there.

We'll find out soon enough right?  The teardown is currently in progress?

[tom66]

Some guy's trying to transplant the S' drivetrain into a Vanagon, of all vehicles...
http://cafeelectric.com/stretchla/

Seeing the damage to parts of that vehicle I predict some teardown will be necessary to get it working ...

I keep hoping a wrecked Roadster will turn up cheap but even crashed and wrecked they go for at least $30k....  people really want those PEMs/batteries!