[Spoiler Alert + Mild Speculation] Tesla has created a monster!

[insaneoctane]

It could be but it does not have to be.
Tesla is free to choose any number below 0.7.

That is kind of my point. To compare apples to apples with the Bolt's range, you would compare 334 vs 238 NOT the number that Tesla has sandbagged. The same sandbagging likely has been used for the 220 number...

Has the 334 estimate that I show been discussed here?

 

[gregincal]

That is kind of my point. To compare apples to apples with the Bolt's range, you would compare 334 vs 238 NOT the number that Tesla has sandbagged. The same sandbagging likely has been used for the 220 number...

Has the 334 estimate that I show been discussed here?

But you would need to look at the raw number for the Bolt to make an apples to apples comparison.

 

[insaneoctane]

But you would need to look at the raw number for the Bolt to make an apples to apples comparison.

The calculations that I showed included the Bolt's raw numbers....

 

[SageBrush]

It could be but it does not have to be.
Tesla is free to choose any number below 0.7.

Or go through the actual 5-cycle testing rather than use the 0.7 fudge factor.
IIRC Tesla noted on the EPA CSI a full testing suite was performed.

 

[Troy]

Hi, everybody. I've figured out how to calculate EPA rated range from the two dyno test numbers (UDDS and HWFET) in the EPA document. As you might know, @omgwtfbyobbq discovered 3 EPA documents. One was for the Model 3 and the other two were for the Model S and X.

The Model 3 EPA document has two dyno test scores: 495.11 miles for UDDS city range and 454.64 for HWFET highway range. However, we didn't know how to convert that to EPA rated range, until now.

Here are the formulas for the Model X and Model S:

Model X EPA rated range =round(73.4%*(0.55*UDDS city range + 0.45*HWFET highway range)) << start with this to test
Model S EPA rated range =round(73.8%*(0.55*UDDS city range + 0.45*HWFET highway range))

Applying the Model S formula to the Model 3 80, I'm calculating 352 miles EPA rated range. At this point, you might be thinking, yes but Tesla said 310 miles EPA. Well, that's not actually true. Tesla never said EPA range for the 310 number. Now, let me walk you through the formulas so you can see for yourself that they are correct:

Step 1: Open this 32-page Model X EPA file here.
Step 2: Scroll down to page 6 and read the Model X 60D UDDS range. It says 267.75 miles. UDDS stands for Urban Dynamometer Driving Schedule.
Step 3: On page 7, read the Model X 60D - HWFET range. It says 276.87 miles. HWFET means Highway Fuel Economy Test.
Step 4: Apply the first formula:
Model X EPA rated range =round(73.4%*(0.55*267.75 + 0.45*276.87))
=round(73.4%*(147.26 + 124.59))= round(73.4%*(271.85))= round(199.54)= 200 miles EPA rated range

You can continue checking the other Model X trim levels in that document. The formula works for them all.

Let's try the same with the Model S:
Step 1: Open this 32-page Model S EPA file here.
Step 2: Scroll down to page 18 and read the Model S 75D UDDS range. It says 345.5 miles.
Step 3: On page 19, the Model S 75D - HWFET range is 358.49 miles.
Step 4: Apply the second formula:
Model X EPA rated range =round(73.8%*(0.55*345.5 + 0.45*358.49 highway range))
=round(73.4%*(190.03 + 161.32))= round(73.8%*(351.35))= round(259.30)= 259 miles EPA rated range

The Model X formula works for all Model X trim levels, however, there is a problem with the Model S. Apparently, the Model S EPA rated range numbers that we know were voluntarily lowered by Tesla except for the Model S 75D. I found another EPA document here that specifically says "Combined range voluntarily lowered" and shows the numbers before they were lowered. Using those original numbers, I was able to match most of the Model S numbers. However, besides this change that threw me off, another change was that at some point the fixed percentage for the Model S changed from 75.4% to 73.8% or maybe from 73.8% to 75.4%. It's hard to tell which one came first but I actually found those percentages in a third EPA document here (you have to calculate them from two of the columns). I can provide more details about these last two documents if needed.

 

[SageBrush]

Hi, everybody. I've figured out how to calculate EPA rated range from the two dyno test numbers (UDDS and HWFET) in the EPA document.

I suggest you try your calc with a couple other EVs before you declare victory.

The basic problem is that the manufacturers can not only report a lower number if they want to, they also have a choice in whether to apply the 0.7 fudge factor or run more involved testing. And moreover, I think they can mix and match. Their is just not enough testing protocol data supplied in the documents we can read to group the cars correctly.

All we really now are the UDDS and highway results. And frankly ? All I care about is highway range.
Since the highway test is well described and we know the speeds, it would not be hard to evaluate the average Aero friction*. That in conjuction with the dyno coefficient data would give a very nice model for estimating fuel consumption at different speeds, albeit with the proviso that we are talking about standard roads and conditions and no air conditioning.

*the lazy can use the 48 mph reported test speed but that will be less accurate.

 

[Troy]

The basic problem is that the manufacturers can not only report a lower number if they want to, they also have a choice in whether to apply the 0.7 fudge factor or run more involved testing.

Tesla has always used the same method. I pretended I didn't know any of the Model X and S EPA rated range numbers and I was able to calculate them from the dyno scores using the formula. Feel free to check the Model X formula against all 5 trim levels in that EPA document.

Trim level, UDDS, HWFET, EPA rated range
Model X 90D 343.92 358.00 257
Model X 60D 267.75 276.87 200
Model X 75D 318.43 330.00 238
Model X P90D 336.86 344.24 250
Model X P100D 382.30 410.02 289

When Tesla wanted a lower score, they simply voluntarily lowered the score. One of the EPA documents I have linked to in my previous message specifically says "Combined range voluntarily lowered" next to most Model S trim levels. However, it still shows what the range was before it was lowered. This way I was able to confirm the formula.

 

[SageBrush]

Here is the highway test in table format showing the vehicle speeds throughout the test in one second resolution.

 

[insaneoctane]

Interesting.... If we use Troy's MS factor of 73.8% to try to estimate the SR EPA rating....
Since there seems to be some controversy around what the actual battery pack sizes really are, I calculated a range of battery sizes for both the LR and the SR:

SR/LR> 75     76     77     78     79     80
50    234    231    228    225    223    220
51    239    236    233    230    227    224
52    244    241    238    234    231    229
53    249    245    242    239    236    233

Does anybody see anything interesting at the intersection of LR=80 & SR=50 prediction? Coincidence?
The math behind this table is just Troy's EPA prediction for LR scaled for different battery sizes

 

[insaneoctane]

Here is the highway test in table format showing the vehicle speeds throughout the test in one second resolution.

Do you have the link to the UDDS too?

 

[SageBrush]

Do you have the link to the UDDS too?

LInk

 

[donkemaen]

Does anybody see anything interesting at the intersection of LR=80 & SR=50 prediction? Coincidence?
The math behind this table is just Troy's EPA prediction for LR scaled for different battery sizes

Since there are three modules in the LR and two in the SR I think the usable energy would be 2/3 for the SR compared to LR.
Anything else would be strange and imply a difference in the modules.

 

[Troy]

Hi. I want to add a little more information. The multipliers for each car can be found in this excel file on the EPA website but a little clean-up is needed. The file contains ICE cars too but there is a column called atvType and it says 'EV' next to all EVs. So I sorted by that column and deleted the other rows. Then I divided the column city08U by column UCity to calculate a city multiplier and divided column highway08U by UHighway to calculate a highway multiplier. Then I took the average of those two to calculate a combined multiplier.

For all other EVs except Teslas, the multiplier is 70.0%, except the 2017 Hyundai Ioniq Electric which has 66.75% for some reason. Anyway, the formulas are all the same except the multiplier.

Model X EPA rated range =round(73.4%*(0.55*UDDS city range + 0.45*HWFET highway range))
Model S EPA rated range =round(73.8%*(0.55*UDDS city range + 0.45*HWFET highway range))
Chevy Bolt EPA rated range =round(70.0%*(0.55*UDDS city range + 0.45*HWFET highway range))

The screenshot is from the cleaned up Google Sheets version I created for myself. You can find it here. By the way, if you want to search for dyno scores for other car models, select 'Certification Summary Information' in the first droplist on this page.

 

[JeffK]

I don't like when multipliers are different for the same manufacturer.

Can we figure out how those multipliers (from Tesla) were determined exactly?

 

[SageBrush]

I don't like when multipliers are different for the same manufacturer.

My thought as well, although the differences Troy came up with are pretty small.

 

[JeffK]

My thought as well, although the differences Troy came up with are pretty small.

My only thought is that it could be a function of weight differences... For example there are two Model X 90D AWD models with two different multipliers in the table... perhaps a different seat configuration changing the weight of the vehicle?

 

[Troy]

My thought as well, although the differences Troy came up with are pretty small.

These are not multipliers that I came up with. They are in the EPA document. I was trying to find multipliers and not succeeding. Then I realized that the file already has some hidden multipliers. So I tried those and they worked perfectly.

 

[SageBrush]

Then I realized that the file already has some hidden multipliers.

Now that is interesting. Where are they in the document ?

 

[Troy]

@SageBrush. The numbers are inside a different EPA document called vehicles.csv. I described this in detail in #353. Let me add a little more detail.

1. Firstly, open this tab here to see how the final result should look like. Look at the blue column headers. You need these 4 columns. Also look at the formulas in C2, F2 and G2 that I used to extract the hidden multipliers. By the way, when you find the multipliers, don't test Model S dyno numbers first. Start with Model X. Now that you understand how it should look like, let's move on to the actual EPA file.
2. The multipliers are inside an EPA document called vehicles.csv here. Unzip the file and open it in Excel or upload to Google Sheets.
3. Freeze top row
4. Sort by column 70, "atvType"
5. Delete all rows except "EV" under column 70
6. Find the columns city08U and UCity and move them side by side and add a blank column next to them.
7. Let's say city08U is now in column A and UCity in column B and the blank column is C. In C2 enter =A2/B2 and drag down.
8. Now repeat the same for highway08U and UHighway
9. Then take the average of the two columns you added.
10. When you find the multipliers, start testing with the Model X, not with the S. S is more complicated. See last paragraph of #345.

As a side note, I have found vehicles.csv on this page by clicking on the link called "Zipped CSV File" above the table. Also, on the same page, the "2017 Datafile" is important too because this is the file with the original Model S EPA scores before Tesla voluntarily lowered them. Those range numbers are hidden inside a formula in the last few columns. Dyno scores won't match unless you use original range numbers, not voluntarily lowered range numbers. The exception is Model S 75D. That one matches because they didn't voluntarily lower the number.

 

[insaneoctane]

@Troy great find and quite interesting! Are you sure the multiplier is an average of the 2 newly calculated individual city/hwy multipliers, or (more likely) most accurately arrived at by:
0.55 * new city multiplier + 0.45 new hwy multiplier
EDIT: The 2 numbers are so close, I don't know that this really even matters....

Anybody know why Tesla would voluntarily lower their EPA #s on the Model S/X where they have had zero competition?