Model X towing 5,000 up mountain passes at the speed limit?

[stopcrazypp]

This is a great idea. I realize that chilling the battery limits the current that it can produce, but that is more in the context of Insane Mode launches. If you can get the temps down 10-20C from normal that will give at least a few miles of buffer. Hopefully they put in a much bigger heat pump/condenser, but based on the small air inlets in the front bumper it doesn't look likely.

I actually didn't include the battery for this reason. Right now we are unsure where the thermal limit is, but I think the motor is a good guess given the motor cooling has been an issue previously with the Roadster. As you put it, the most you can do on the battery is a little less than normal, but nothing too extreme. However, for the motors and inverters you can cool it down more. The basic idea is to take advantage of thermal inertia.

 

[Yggdrasill]

I don't think the motor conditioning would make much difference. The issue is with the rotor, which is constantly cooled as long as the car is moving. If you don't cool the rotor, it will overheat, even with mild loads. Assuming a 10 kW power consumption, probably around 500W will be generated in the rotor. The rotor doesn't have much mass so the temperature climbs quite rapidly. If you're going to precondition the motor while driving, you need to work against the heat being generated, and that is probably difficult. You can't put the cooling exactly where the heat is being generated, you're stuck with only cooling inside the drive shaft, so you end up with a temperature gradient from where the heat is being generated to the drive shaft. Of course, cooling the drive shaft more will lower the max temperature somewhat, but it should mostly just work to increase the slope of the temperature gradient. In conclusion, I think you will see some improvement, but not very much. A few additional seconds at max power maybe.

 

[Vitold]

So I asked Tesla via email if the Model X was going to get a beefed up cooling system to handle tow loads, this is their reply:

"That is a very good question. At this point we are working on the specs and the cooling systems abilities. Stay tuned and we will have more information before the end of the year."

Did you ask this question in 2014? I would expect Tesla to have it figured out already since they delivered their first models, one even towing air-stream trailer.

 

[X-Wing]

This is very scary. It seems to show that the Model X is still many months from being fully designed, tested, and validated. I'm guessing that the Model X vehicles delivered on stage were hand built. I wonder if the production line is even capable of running yet?

No kidding. :scared:

Plus only giving Signature buyer 24 hours to make the change at the last minute? Not only is the car not ready, the company is also not ready. Very poor communication from Tesla once again.

 

[ratsbew]

I don't think the motor conditioning would make much difference. The issue is with the rotor, which is constantly cooled as long as the car is moving. If you don't cool the rotor, it will overheat, even with mild loads. Assuming a 10 kW power consumption, probably around 500W will be generated in the rotor. The rotor doesn't have much mass so the temperature climbs quite rapidly. If you're going to precondition the motor while driving, you need to work against the heat being generated, and that is probably difficult. You can't put the cooling exactly where the heat is being generated, you're stuck with only cooling inside the drive shaft, so you end up with a temperature gradient from where the heat is being generated to the drive shaft. Of course, cooling the drive shaft more will lower the max temperature somewhat, but it should mostly just work to increase the slope of the temperature gradient. In conclusion, I think you will see some improvement, but not very much. A few additional seconds at max power maybe.

It's probably not possible from an engineering standpoint, but if the inside of the rotor could serve as an evaporator chamber where the AC compressor supplies freon to the rotor and is then expanded directly inside the rotor...that could provide substantial cooling ability.

 

[Cosmacelf]

Did you ask this question in 2014? I would expect Tesla to have it figured out already since they delivered their first models, one even towing air-stream trailer.

Yesterday. It's kinda how the company rolls. As usual, the answer is ambiguous. Does this mean they haven't even done the engineering, and the cooling system in the founder cars might suck? Or does it mean product management is so far behind, that they haven't asked this rather obvious (to us) question of the engineering team? I would ask Tesla again, but I'm pretty sure I wouldn't get an answer to that question...

 

[Uncle Paul]

Tesla is delivering their standard Model X with a small towing hitch, probably with no additional cooling capacity.

An option for a towning package is available where a larger hitch is installed, and modification to various components, such as brakes and electronic controls of the car are upgraded to allow for additional weight.

I would imagine, that at some future date, an even heavier towing package might become available.

This is no different than for ICE vehicles on the road. They, also, have towing limitations, that restrict how much they can tow and the amount of fuel required to get the job done.

To me, just getting an electric vehicle to tow anything, is a great accomplishment.

 

[P90D]

Based on real world experience -

Yes, I can tow 25,000 lbs with my F-350
Yes, I can tow that weight at speed limits, on level terrain.
No, I can NOT tow that weight, at limit, on steep grades.

Pick any two out of three. Not all three. And there is absolutely no reason whatsoever to think that a Model X would avoid this close-to-fundamental law.

Get your 350 checked. It's a diesel, right?
Look at any race track paddock on a race weekend and you'll see Ford and GM heavy duty dual rear wheel pickups used as tow vehicles, many with trailers at their rated capacity with three cars, the trailer itself being not light, and with spares and tools. It's even a bit of a struggle to stay under 20K lbs hence the appeal of ever upgrading to newer models with higher limits. Of course, mpg can be jaw-dropping... 10 mpg being a very good number ...

- - - Updated - - -

Have a look at nitrous for cooling if you're curious about how this works (and how phenomenally impractical it becomes.)

I'd like to think that one of the technology R&D frontiers where Tesla will make new discoveries is the boundary between electricity and heat. Whether it's thermocouples or microturbines, or some entirely new chemistry (heat storing metals that act like heat sink powered springs?) the energy loss to cool something right next to the energy loss to heat something is one of those "is this the best we can do?" shortcomings of all cars. It seems to me that ... somehow ... a car needs to be a symbiosis of heat sources and cooling, sort of like two air-conditioning compressors working opposite each other -- the hot side of one produces the energy to operate the other to produce the cool side to cool the other in a "perpetual motion machine" paradox of lossless commutation between electricity and heat and cold.

Of course, in the world today, all these systems are barely 20% efficient. A failing grade. We're slipping down that grade. We need to at least level out to a 50:50.

Small steps.

 

[Cyclone]

This is a great idea. I realize that chilling the battery limits the current that it can produce, but that is more in the context of Insane Mode launches. If you can get the temps down 10-20C from normal that will give at least a few miles of buffer. Hopefully they put in a much bigger heat pump/condenser, but based on the small air inlets in the front bumper it doesn't look likely.

The S P90D has a Max Power mode that preps the battery for maximum output. This sounds like a natural extension of that mode.

 

[Canuck]

Not only is the car not ready, the company is also not ready.

A little extreme, don't you think? Are you telling all the Roadster and Model S drivers out there that the company that built their car is not ready? If so, you might get some push back. For me, your "not ready" company produced a car that is much more ready than any other car I have driven.

I've seen more than few ICE vehicles overheat, and some even catch fire, going up the Coquihalla Hwy (a climb of over 4,000' -- that 9,000' foot climb in Colorado must something!). I imagine the Model X will need some pretty good cooling system to do that climb in the summer towing 5,000 lbs. I did it lots in my Silverado then Tahoe towing a 19' travel trailer but I was always in the slow lane. The loaded semi's do it at a snail's pace and they have 3 lanes at the steepest inclines for that reason. The crawling lane, slow lane and fast lane. I just hope the X is in the slow lane when towing and not the crawling one!

 

[AudubonB]

My F-350s' Powerstroke diesel (6.4l - it's a 2008) is in fine shape, for what it is. Brand new injectors; DPF filter properly burned out, and so on. Only pickups out there that can outperform it are ones that have been chipped, straight-piped, and otherwise illegal-ized.

I stand by my statement: in any given situation you can have:

1. Maximum towing capacity
2. Maximum speed
3. Maximum grade

BUT only two out of those three. Regardless of whether you're burning diesel, electrons, nitrous oxide or fairy dust.

By the way, by grade I mean what we see on the Al-Can. I don't know whether those are 1:8 grades, 10% grades or what, but I-70's Loveland Pass, I-80's Parley's Summit don't compare. Elk Park Pass outside Butte is the only grade I can think of at the moment that comes close, but not equal, to what northern BC's Peace River country throws at you again and again.

 

[aesculus]

So I asked Tesla via email if the Model X was going to get a beefed up cooling system to handle tow loads, this is their reply:

"That is a very good question. At this point we are working on the specs and the cooling systems abilities. Stay tuned and we will have more information before the end of the year."

When I bought my 2001 Acura MDX in late 2000 (one of the first production cars) they were selling the hitch separate from the suggested transmission cooler that was going with the towing package. About a month later they refused to sell anyone the hitch only because of fears that people would tow with the car (6000 lbs max) without the cooler. We just used our hitch for the bike rack when hauling more than two bikes.

 

[AmpedRealtor]

This is very scary. It seems to show that the Model X is still many months from being fully designed, tested, and validated. I'm guessing that the Model X vehicles delivered on stage were hand built. I wonder if the production line is even capable of running yet?

Considering they only delivered 6 cars, I think you have your answer.

 

[eloder]

Considering they only delivered 6 cars, I think you have your answer.

6 weeks between S founder deliveries and MS deliveries.

History seems to be very quickly forgotten