Tesla cuts 60kWh Model S, entry-level Model S is now 70D.

[vgrinshpun]

I don't need to find or create an competing theory in order to invalidate yours. I've explained several times how your source data is questionable, and your assumptions created to support your theory. You're simply trying too hard to prove a theory that really has very little actual support of the facts. I'm not privy to Tesla Motor's inner workings, so I'm not even going to try and guess why they changed the EPA rating. But new battery chemistry is one of many, many, possible reasons -- marketing being probably the most plausible one.

You even fabricated one of your data points because you needed it to fit your theory:



What is the *real* range for a 60D? In fact, immediately following your post, this was posted:



Are you using your fabricated 60D range of 212 in your theory, or did you update it to use 225 as Tesla claimed?

And you seem to ignore or discount what was reported concerning the 70D battery pack:

Man, this is intense: “The lady doth protest too much, methinks”, “fabricated”...

I say that you are engaging in personal attack and need to cut on theatrics and chill-out. Doing breathing exercises before posting might help.

Going back to the essence of the issue, you, of course, disprove nothing. You actually did not really lay out all your objections clearly and consistently, rather side with others who note their objections, or attack things that are really peripheral to the conclusion of my theory.

So I will try to summarize your objections and rebut them here.

You even fabricated one of your data points because you needed it to fit your theory

First, word fabricated is thoroughly out of place here. I openly, in great detail stated my assumption/calculation for everybody to see and evaluate, so ascribing intent to mislead and manipulate is simply wrong here. Most importantly, the graph is nothing to do with my theory – it is just graphical representation of the fact that increase in range observed in 70D is too large to be fully attributed to added 10kWh of battery capacity, or the addition of the dual motor drive. This conclusion is actually seem to be universally accepted by everybody.

More over, the simple extrapolation I did is the same as saying that increase in range of 60D over 60 is proportional to the increase in range of 85D over 85, a totally reasonable assumption, given that these are variants of the same car, with similar battery packs and drive train options.

Are you using your fabricated 60D range of 212 in your theory, or did you update it to use 225 as tesla claimed?

Not sure why you are asking this question, as I specifically explain that my point is based on this calculated range of 212. Using 225 miles at 65mph would be, of course, wrong as all range numbers I use are based on EPA range, not range at 65 mph.

Still too many unknowns (options, etc) and assumptions made to be able to make any scientific conclusions based on two weight data points. It’s really apples and oranges. Or apples and something else, Sorry

If you would actually spend some time reading the sources with weight data that I referenced, you would notice the following:

• The Car and Driver Instrumented Test article does list all of the options on the car: 19-inch wheels and tires, next gen seats, metallic paint, special wood trim and cold-weather package. The 70D was weighed at 4608lbs.
• The R&T article was published on the day of the D event, 14 minutes after it was scheduled to start. (October 9 2014, 7:14pm). It is clear that data in the article was **not** based on R&T sneaking out three variants of the cars from under the nose of Tesla folks and running them to the local scale to weigh them, and then stealthily returning the three cars to the unsuspecting Tesla. The data was clearly provided by Tesla and published as soon as news embargo was cleared with the start of the event. These data, as is the case with all manufacturer’s data list weights without options, unless stated otherwise. So the weight of the base 60D car according to Tesla data is 4597lbs (including 176lbs added associated with the dual drive unit).
• So these two data points are hardly apple and oranges. The options listed for 70D can’t add 90 pounds or so to the weight of the car that would actually make any material impact on my conclusions. In fact the 11 pounds difference between the two numbers is likely due to the cold weather package that is part of 70D, but not the 60D.

Regarding the David Noland’s article, as I mentioned before, he did not include the name of the Tesla spokesman, leading to the conclusion that it is a local Service Center source. As anybody following Tesla for any length of time knows, sources at the SC are not known for their accuracy.

In conclusion, while I still call my musings on this subject a theory, it is a very plausible one. Your objections disprove nothing, as they actually are based on your assumptions which are inaccurate.

 

[blakegallagher]

OK, the verdict is in.

According to the Car and Driver instrumented test (thanks to Anticitizen13.7 for posting) the weight of the 70D is 4608lbs, while the weight of now defunct 60D was essentially the same - 4597lbs according to the Road & Track data back from Oct. 9 article published right after the "D" event. This is consistent with my theory that the battery in 70D weighs the same as the battery in 60, contains the same quantity of cells, but each cell, due to higher volumetric and gravimetric energy density contains about 16.7% more energy. This is consistent with the conclusion that 70D contains new generation of the cells, due to show up in Model X, and, perhaps a little later in other variants of Model S.

Hello 300+ EPA range in Model S??

Thanks for all your analysis on this Vgrinshpun. I believe your right on the mark here. I certainly don't think you would ever try to bend numbers to make a theory work. +1

 

[HankLloydRight]

Regarding the David Noland’s article, as I mentioned before, he did not include the name of the Tesla spokesman, leading to the conclusion that it is a local Service Center source.
.

It boggles my mind how you can make this "conclusion" with absolutely zero data to back it up. Just because he *didn't* say who the "Tesla spokesperson" was, that means it was some random SC person? Really?

In conclusion, while I still call my musings on this subject a theory, it is a very plausible one. Your objections disprove nothing, as they actually are based on your assumptions which are inaccurate.

I have made zero assumptions in refuting your "facts". I have only called into question their accuracy and validity, which makes their use in developing your conclusions rather weak. If you had stronger facts (as I mentioned-- comparable weights with a control, and accurate, not imputed, consumption data) then you would have a plausible theory. I'm also not "disproving" your theory as I don't have real facts either so I can't offer an alternate hypothesis. As anyone doing a good scientific study, you have to be open to people challenging your stated facts and assumptions and the conclusions made with those facts. And doing that is not a personal attack.

 

[vgrinshpun]

We are at risk going circular here, but you posted some things which are verifiably wrong, and I am going to point them out.

I have made zero assumptions in refuting your "facts".

You assumed that I fabricated one of my data points because I needed to fit my theory. This assumption was wrong, as demonstrated in my previous post.

You assumed that there are unknown options for 60D and 70D cars for which I used weight information. This assumption was wrong, as demonstrated in my previous post.

I'm also not "disproving" your theory as I don't have real facts either so I can't offer an alternate hypothesis.

Here is your words: "I don't need to find or create an competing theory to invalidate yours."

As anyone doing a good scientific study, you have to be open to people challenging your stated facts and assumptions and the conclusions made with those facts. And doing that is not a personal attack.

I am open to people challenging what I post. I am **not** open to people saying that I fabricated my facts and using theatrical references to question my intent: "The lady doth protest too much, methinks". This **is** personal attack and you shouldn't have engaged in it.

 

[JRP3]

Regarding the David Noland’s article, as I mentioned before, he did not include the name of the Tesla spokesman, leading to the conclusion that it is a local Service Center source.

A bit of a leap there. No name = local SC source? For reasons I stated above I think David has some contacts a bit higher up at Tesla. There is just as much evidence that he spoke to Elon as there is that he spoke to a local SC employee: None.

 

[vgrinshpun]

A bit of a leap there. No name = local SC source? For reasons I stated above I think David has some contacts a bit higher up at Tesla. There is just as much evidence that he spoke to Elon as there is that he spoke to a local SC employee: None.

I think that you tend to look at data one piece at a time, which is perfectly fine if all the data agree. I am looking at **three** pieces of information and trying to arrive at logical (in my view, of course) conclusion.

You are choosing to treat this article as definitive proof that 70D and 60 have the same cells, while ignoring data indicating that 70D and 60D have the same weight and the fact that 70D has higher range that can be explained by addition of 10kWh of battery and dual motor drive.

What I am saying is that I have enough of a doubt about the information provided in the article (see my previous post for the reasoning) to **not** dismiss data indicating that 70D and 60D have the same weight and 70D has range that is higher than can be explained by additional 10kWh of battery and dual motor drive.

 

[JRP3]

I don't think I've ever said we have definitive proof of anything. I've said all along that there is no conclusive data to say for sure one way or the other. The weight issue has a number of possible solutions. The "advertized" weight of the non existent "60D" could be inaccurate. The dummy cells which we know for a fact were in the 60 packs had to weigh something and replacing those with real cells might not change the weight as much as you suppose. We probably can't settle this until someone gets their hands on a salvaged 70D pack, or we get an official Tesla statement from a source we can all agree is 100% credible.

 

[WarpedOne]

"Increased number of cells" theory has one major flaw - is says nothing about "Why".
It is one thing to quietly accept such things in movies, it is another thing in reality.

One forum member tried to explain it in terms of "better optimization of battery capacity".
I for one don't see any sense in such explanation. Not in the light of raising the price for only 5k, including SC and dual motors.
Smaller battery is always more efficient than bigger one (weight!) and costs less (less cells!).

I may buy into "increased count theory" when someone offers a plausible reasoning for "why".
"Higher capacity theory" has a nice explanation for why - Model X and smaller production of next gen cells.

 

[vgrinshpun]

I think that given information that we have it is much more likely than not that 70D has next gen. of cells. We will know if it is true or not in July, when Model X configuration tool will become live. Seeing Model X with 70 and 100kWh packs would indicate new gen of cells. Model S 85 to 100kWh changeover could follow at some later date.

 

[JST]

"Increased number of cells" theory has one major flaw - is says nothing about "Why".
It is one thing to quietly accept such things in movies, it is another thing in reality.

One forum member tried to explain it in terms of "better optimization of battery capacity".
I for one don't see any sense in such explanation. Not in the light of raising the price for only 5k, including SC and dual motors.
Smaller battery is always more efficient than bigger one (weight!) and costs less (less cells!).

I may buy into "increased count theory" when someone offers a plausible reasoning for "why".
"Higher capacity theory" has a nice explanation for why - Model X and smaller production of next gen cells.

Wouldn't the Model X explanation apply to either? If Tesla needs a higher pack capacity for the Model X to meet the "at least" 200 mile real-world range target Elon has talked about, why would it matter how they got there?

 

[Doug_G]

vgrinshpun and HankLloydRight need to dial it back, or I will banish the discussion to snippiness.

-mod

 

[Klaus]

Thank you!

 

[WarpedOne]

Wouldn't the Model X explanation apply to either? If Tesla needs a higher pack capacity for the Model X to meet the "at least" 200 mile real-world range target Elon has talked about, why would it matter how they got there?

It would If one accepts that a new car will be introduced in 2015 with less range than a car introduced in 2012.

If that happens, I would scream at Elon "where are those better batteries you keep talking about?" at every opportunity I got. It would be a direct negation of the base premise the whole company stands on - the batteries are improving.
It could very well mean a death blow to company as it threatens the understanding that batteries are the future. What future if current batteries are no better than those from three years ago?

So, no, I fully expect Model X will have ~100kWh battery at introduction and similar or a bit higher range than S85D does. This demands newer chemistry as X will have same pack format. And newer chemistry is already in the pipeline to be produced in GF next year with ~15% higher density. You think those cells are not produced in smaller runs already? I think they are.

 

[HankLloydRight]

Ok, let me try this a different, "dialed back", way.

Ever since you posted the above graph, something just didn't seem right to me, and now I've figured it out.

You are graphing Wh/Mile versus kWh pack size. But there is a linear relationship between those two -- since Wh/mile (y axis) is just kWh(x-axis)*1000*95%/range. So when you remove pack size variable from the y-axis, what you're really just graphing is EPA Range versus kWh pack size.

I've taken all your numbers and same assumptions to create virtually the same graph removing the dependent axes. This is Range (y-axis) versus kWh pack size (x-axis)

The top solid orange line is the EPA ranges of the 60D(imputed), 70D, and 85D. The dashed orange line is a straight line between the 60D and 85D points. The midpoint at the 70D marker (236) is what you would expect the 70D range to be if it were made from the same cells as the 60D/85D.

The blue lines mirror the same values as the orange line, except for the non-D variants. Just as you did, I created an EPA range for a non-existent S70 using this formula: (265*245)/270=240 miles.

The point of this is to look at two numbers for the 70D on the orange lines. If we assert for a moment that the 70D were made of the same cells as the 60D/85D, you'd expect the EPA Range to fall at or near the linear line between 60D and 85D, or 236 miles. But it doesn't, it's actually 245 miles. That is an increase of 9 miles over the expected value, or just an 3.8% improvement.

As discussed elsewhere in this thread, even if there were 200 pounds more due to the same old cells being used in the 70D over the 60D (200 pounds would be about 2000 more cells over the 60D), the addition or removal of 200 pounds (say, one adult passenger) has a negligible affect on range, and certainly not 16%. So I think saying the 60D and 70D cars weigh the same (or not) does not really factor that greatly into this discussion of increased energy density.

Finally, if we look at your original graph, you can see this same difference. Your 70D wh/m value is 271. If you go straight up to where the 70 kwh pack intersects the orange line, it's about 281 Wh/m. So that difference is 10 Wh/m, or 3.7%. Using the same logic, if the 70D were built with the same cells, you'd expect the Wh/m to be around 282, but it's only 3.7% lower.

So it appears that the 70D packs are slightly more efficient (~4%) than their 60D/85D counterparts, but does that mean there's newer cell technology, or just other incremental improvements along the way? That I can not answer, but I would bet on the latter.

 

[qwk]

I hate to burst someones bubble here, but the early 60kwh packs had some sort of dummy module parts in the front of the pack(where there are 2 extra modules for the 85kwh). I don't know if they were balast, or just a space holder, but most likely a ballast of some kind. Something to take into consideration when comparing pack and car mass.

 

[WarpedOne]

Any pics of those dummy modules?
I don't remember seeing any pictures, just guesses that turned into urban legend.

 

[jvonbokel]

"Increased number of cells" theory has one major flaw - is says nothing about "Why".
It is one thing to quietly accept such things in movies, it is another thing in reality.

One forum member tried to explain it in terms of "better optimization of battery capacity".
I for one don't see any sense in such explanation. Not in the light of raising the price for only 5k, including SC and dual motors.
Smaller battery is always more efficient than bigger one (weight!) and costs less (less cells!).

Efficiency does not correlate linearly with the battery size. There is a point of diminishing returns as you add cells (weight) to increase range. I would presume this is well above the 7104 cells it takes to store 85kWh, but we don't really know where that point is. It may well be at/near 70kWh.

Remember that the original S60 and S85 were rated at 208 and 265mi respectively, but those don't imply a linear correlation (208/60 does not equal 265/85), and we can say with some certainty that those two models were at least nearly identical other than their battery packs. They had different efficiencies (95MPGe and 89MPGe) due to their differing weights.

You are graphing Wh/Mile versus kWh pack size. But there is a linear relationship between those two

Not directly linear, due to weight considerations.

The point of this is to look at two numbers for the 70D on the orange lines. If we assert for a moment that the 70D were made of the same cells as the 60D/85D, you'd expect the EPA Range to fall at or near the linear line between 60D and 85D, or 236 miles. But it doesn't, it's actually 245 miles. That is an increase of 9 miles over the expected value, or just an 3.8% improvement.

Your chart illustrates rather well why 70kWh may have been an ideal size. If it generates a better efficiency (range/kWh), then it represents a better value. And in fact, the EPA rates it at 101MPGe, better than both the original S60 and S85, and a tick better than the 85D (100MPGe) as well.

So it appears that the 70D packs are slightly more efficient (~4%) than their 60D/85D counterparts, but does that mean there's newer cell technology, or just other incremental improvements along the way? That I can not answer, but I would bet on the latter.

Agreed. However, if the difference could be attributed to "other incremental improvements", then I would think the EPA would revise (upward) its range estimates for the 2015 S85 and 85Ds vs their previous years. It's possible they don't actually test all models every year, but I would think that could lead to manufacturers attempting to lock in good results in the first year of a car's production run.

 

[HankLloydRight]

You are graphing Wh/Mile versus kWh pack size. But there is a linear relationship between those two

Not directly linear, due to weight considerations.

Yes, that relationship is reflected in the EPA Range value (the m denominator in wH/m).

I'm talking about the direct (linear) relationship between the numerator (wH) and the x-axis (kWh). That relationship is Wh=1000*kWh*.95%.

If you remove the dependency, you're left with just EPA range on the y-axis.

 

[qwk]

Any pics of those dummy modules?
I don't remember seeing any pictures, just guesses that turned into urban legend.

I don't have pics, but have seen it with my own eyes. There used to be pics somewhere on the web, but I just did a quick search, and cannot find them anymore.

 

[jvonbokel]

I don't have pics, but have seen it with my own eyes. There used to be pics somewhere on the web, but I just did a quick search, and cannot find them anymore.

My understanding was that there were no dummy modules, but that each module had fewer cells, and thus the pack had the same number of modules and effectively the same weight distribution.