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jgs
Active Member
Define what you consider to be "significantly".
It has been speculated on, I think in this very thread, and elsewhere. My guess is no more than 4 inches narrower.
If the model 3 did not have ludicrous, I might agree with you. I would say the model 3 pack is less expensive, with a higher C rate. But with the all the Tesla models close in wheelbase, and possibly width, I think making one pack style would be attractive to Tesla.
The financial benefit of Musk's alien dreadnought pack building machine could then be applied to all cars.
I remember one person at the reveal saying the back seat was tight for three adults. But looking from above, it looks like there is less shoulder room in back than in front.
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Red Sage
The Cybernetic Samurai
Oh, I thought very much the same, until I saw the animation behind Elon Musk at the Model ☰ Reveal Part I. I could tell from that display that the battery packs would be completely different in dimensions and shape. I do not believe they will be modifying the Model S/Model X to accept that style of battery pack at all.
I don't think that animation reflected the real pack. The cells were spaced so it looked to be air cooled. But with the needed C rate, and cylinders, an air cooled pack seems unlikely. I suppose they could design the new subpack assembly of cells to fit the old pack design. That way the manufacturing process would be the same up to that point. Although I'm not sure of the voltage of each sub assembly.
I do expect the S/X to use gigafactory cells. But I suppose there is no reason for those cells to go into a new pack.
I'm sure this must have been mentioned before somewhere, but Randy Carlson posted an excellent piece on Seeking Alpha regarding the possibility of the use of an air cooled pack for the M3. He also speculates about the possibility of a HUD in the M3, which I found to be pretty compelling as well.
stopcrazypp
Well-Known Member
I don't believe you can tell the cell spacing from the animation. The modules were presented as just a gray blob (there were three rows of holes per module, but it obviously did not represent all the cells).
I doubt Randy's sealed air cooled hybrid system would save any money over robot installed glycol lines. He still has a heat pump and radiators. Plus he had the pack at $6K but with the supercharging in the base price of the model 3. So he has room to adjust his budget up and still hit $35K. I'm guessing at a 55kWh pack that costs Tesla $10K in 2018.
I do hope he is right on the DLP HUD. But it does seem too exotic for this car.
stopcrazypp
Well-Known Member
The first point has nothing to do with liquid cooling specifically (having the contactor/fuse there can be the explanation). The second point actually was the exact opposite of what I expected (Randy saying a larger module is indicative of an air cooled cell).
Air cooled packs typically have less cell spacing than liquid cooled packs because they don't need a path for the coolant to run. Rather, they have the cells packed closely together and then have metallic heat exchangers between the cells to transfer heat. The reduction in overhead from smaller cell spacing is what Nissan brags about (for both the Leaf pack which uses passive air cooling and the e-NV200 which uses active air cooling).
I believe Randy is referring to active air cooling, which would indeed require increased spacing between the modules to be effective. Passive cooling via heat exchangers I think has proven itself to be sub-optimal, especially in very warm climates.
PJFW8
Red Menace may hurt me
Red Sage
The Cybernetic Samurai
Was that with mirrors extended or folded? Seems to narrow to be with mirrors extended.
Model S is 77.3" with mirrors folded, 86.2" extended.
I'm pretty sure that's with mirrors folded. That generally is the norm when quoting car widths. Basically the 3 will be 3" narrower than the S.
The norm for width dimensions used to be with and without mirrors, not with and with folded mirrors. That's changing now that many cars have powered folding mirrors. Tesla quotes the width with folded mirrors but manufactures often quote "without mirrors."
Lexus states width "with mirrors folded in". BMW only shows this:
It's unknown what reference MT used for their 74" number; so, at least in my mind, there are a few inches of uncertainty around that data point.
The norm for width dimensions used to be with and without mirrors, not with and with folded mirrors. That's changing now that many cars have powered folding mirrors. Tesla quotes the width with folded mirrors but manufactures often quote "without mirrors."
Lexus states width "with mirrors folded in". BMW only shows this:
It's unknown what reference MT used for their 74" number; so, at least in my mind, there are a few inches of uncertainty around that data point.
Folded mirror width is generally pretty close to no mirror width. On the Model S I'm not sure if the folded mirrors actually stick out beyond the wheel wells at all.
Well this was an absolutely exhausting read. A few points:
1. Keeping the wheelbase the same as the Model S while reducing overall size is indeed the most economical path. Anything you can keep the same between models means not only the possibility of swapping parts, but the much more important thing: reducing tooling costs. And reducing tooling costs for motors and batteries is crucial for Tesla because these are not normal auto manufacturer costs.
2. It's almost impossible to estimate any dimensions in this manner, and especially overall length is flat out impossible. The *only* dimension you might get close to is wheelbase but everything else will come out dramatically shorter than expected. There's three factors in that which almost no-one is bringing up:
A. Linear perspective foreshortening: If we imagine a flat plane from the sidewalls of the tires, every feature that is further away from us will be shrunk more and more the further it is back. Since the total vehicle length is measured from the *centerline* of the vehicle, it will be much much shorter than we can see. It might be possible to compensate for this if we could see the far tires and calculate the centerline and the proportional factors to scale to... but we can't... soo, that's a no-go. Foreshortening means you also can never even SEE the very front tip and rear edge of these cars in this kind of photos. What you guys are measuring against is some random tangent along the curve of the bodywork.
B. Curved perspective foreshortening: Curved objects dramatize perspective effects and can objects look *longer* from the side than they should be, even if you can compensate for linear perspective effects. How's that for weird?
C. Camera lens distortion: the length of the camera lens can change the style of perspective... a really long lens will reduce foreshortening or "flatten" the image. In the above example, a very long lens could make the far tires appear almost in line with the near tires. On the other hand, a short lens could have the opposite effect, increasing foreshortening and making the far tires appears much closer together and smaller than the near tires. Wider lenses also tend to have barrel distortion, which makes objects in the center of the field bigger, and objects at the edges of the field shorter. This effect would make the wheelbase appear longer than it is, the height taller than it is, while simultaneously making the overall length of the vehicle appear shorter. Distance from the camera to the subject also exaggerates these effects... the closer the camera is to the subject, the greater the distortion. And since you have no way of knowing what kind of lens is being used for these various shots, comparing different photographs from different sources would be completely useless... even IF you had the exact dimensions, you would never be able to make the kinds of comparisons you are looking for.
The video comparison shots are probably the most informative, but even with those... unless the tires closest to us followed EXACTLY the same path to the millimeter, perspective effects mean the wheelbase could appear longer or shorter. If the car is dramatically narrower as many are suggesting, then if the cars followed the exact same centerline path, the Model 3 would appear shorter than the Model S just by virtue of the perspective effects against the differences in the vehicle widths. The "few inches shorter" could easily be explained by perspective and those shots could very well actually prove they have the same exact wheelbase.
1. Keeping the wheelbase the same as the Model S while reducing overall size is indeed the most economical path. Anything you can keep the same between models means not only the possibility of swapping parts, but the much more important thing: reducing tooling costs. And reducing tooling costs for motors and batteries is crucial for Tesla because these are not normal auto manufacturer costs.
2. It's almost impossible to estimate any dimensions in this manner, and especially overall length is flat out impossible. The *only* dimension you might get close to is wheelbase but everything else will come out dramatically shorter than expected. There's three factors in that which almost no-one is bringing up:
A. Linear perspective foreshortening: If we imagine a flat plane from the sidewalls of the tires, every feature that is further away from us will be shrunk more and more the further it is back. Since the total vehicle length is measured from the *centerline* of the vehicle, it will be much much shorter than we can see. It might be possible to compensate for this if we could see the far tires and calculate the centerline and the proportional factors to scale to... but we can't... soo, that's a no-go. Foreshortening means you also can never even SEE the very front tip and rear edge of these cars in this kind of photos. What you guys are measuring against is some random tangent along the curve of the bodywork.
B. Curved perspective foreshortening: Curved objects dramatize perspective effects and can objects look *longer* from the side than they should be, even if you can compensate for linear perspective effects. How's that for weird?
C. Camera lens distortion: the length of the camera lens can change the style of perspective... a really long lens will reduce foreshortening or "flatten" the image. In the above example, a very long lens could make the far tires appear almost in line with the near tires. On the other hand, a short lens could have the opposite effect, increasing foreshortening and making the far tires appears much closer together and smaller than the near tires. Wider lenses also tend to have barrel distortion, which makes objects in the center of the field bigger, and objects at the edges of the field shorter. This effect would make the wheelbase appear longer than it is, the height taller than it is, while simultaneously making the overall length of the vehicle appear shorter. Distance from the camera to the subject also exaggerates these effects... the closer the camera is to the subject, the greater the distortion. And since you have no way of knowing what kind of lens is being used for these various shots, comparing different photographs from different sources would be completely useless... even IF you had the exact dimensions, you would never be able to make the kinds of comparisons you are looking for.
The video comparison shots are probably the most informative, but even with those... unless the tires closest to us followed EXACTLY the same path to the millimeter, perspective effects mean the wheelbase could appear longer or shorter. If the car is dramatically narrower as many are suggesting, then if the cars followed the exact same centerline path, the Model 3 would appear shorter than the Model S just by virtue of the perspective effects against the differences in the vehicle widths. The "few inches shorter" could easily be explained by perspective and those shots could very well actually prove they have the same exact wheelbase.
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