Ford Range Increase Coming?

[EVer]

I'll take a crack at it.

Assumption: you start with a full charge of ~78.3kWh and drive at 75mph average until it stops.
Known relationship: energy required varies with the square of speed.
Calculation:

Speed 1 (average EPA highway test)	48.300	MPH
Speed 2 (Hypothetical)	75.000	MPH
Efficiency (average for HWY cycle from Tesla EPA filing)	1764.600	Wh/10.25mi
Efficiency (average for HWY cycle from Tesla EPA filing)	0.172	kWh/mi
Speed Ratio^2	2.411	-
Avg efficiency for Speed 2	0.415	kWh/mi
Total Energy Available	78.269	kWh
Total Range at Speed 2	188.557	mi

Source data:
EPA Highway Test Schedule average speed:

Energy Consumption from Tesla EPA testing of Highway Test Schedule:

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[EVer]

No worries. It's the bottom line. 188.6 miles. I went back and made it red, so it should be more obvious.

 

[TheSteelRider]

Ignoring the little voice in my head that I've nicknamed, "Common Sense", I read this entire thread, every post. I went through a "range" of emotions, and my "efficiency" at work today has dropped by an estimated 35% (although your efficiency may differ).

It's really funny how everyone is saying the same thing, differently. That is, to sum it up, YMMV. Can we at least agree on that?

 

[EVer]

The data I used were from 2017, and the associated rating was 310 miles.

I should add a disclaimer: I don't claim there is anything definitive about my post. All I did was take what Tesla reported it took to complete two highway cycles, ratioed that up for the higher speed, and extrapolated to the full battery. The methodology seems sound by may be flawed.

 

[MattG]

So I have to ask: If the vehicle is exactly the same as it was months ago, same design, same parts, but Ford publishes a better "final, official range" than it is publishing right now... Does it matter to you, and why?

I don’t care what the published range is...I only care about real world range, and I have zero confidence getting that answer from any EV manufacturer (though some do seem more realistic than others).

 

[EVer]

I don’t care what the published range is...I only care about real world range, and I have zero confidence getting that answer from any EV manufacturer (though some do seem more realistic than others).

The problem is, real world range depends entirely on the route, the ambient conditions, driving style, etc. It varies from day to day and destination to destination.

 

[DBC]

There is another crucial point: That the achievable percentage of EPA range seems to deviate widely across EV brands. What is important is not the EPA range but the realistic range that you can expect on a road trip. From that perspective, Tesla does far worse than its competitors.

A lot of this flows from the fact that BEVs are most efficient when they can use regen. The way this plays out is that there is a highway range, a city range, and a 2/3rds - 1/3rd combined range. BEVs can use regen on the city cycle and hence get more city range than highway range. ICEs are relatively less efficient at lower speeds and can't use regen, so they get more highway miles than city miles. Consequently BEVs will exceed the combined range in city driving and fall short in highway driving; ICEs will exceed the combined range when highway driving but fall short in city driving.

A corollary is that vehicles with a larger difference between city and highway efficiency will deviate more from the combined cycle number and one which has a small difference will deviate less. Hence a BEV which has far more city range than highway range will deviate more from the combined number when driven on the highway cycle than a BEV with closer city and highway ranges.

This is apparent in the Car and Driver test of the Porsche Taycan. That car gets 4% more range when driving on the highway than when driving in the the city, so you'd expect it to beat the combined City/Highway. And indeed it does. It gets exactly 4% more range (209 miles) than the combined range (201 miles). The exact match is really coincidence -- the combined number is equally weighted City and Highway -- but what isn't coincidence is how closely the highway range predicts the range at a steady 75 MPH.

Car and Driver seemed to wet their panties over the fact that the Tesla they tested didn't get near its combined range number. That was a surprising result and I have no explanation for it. However, CARWOW did a less controlled test (but better than Car and Driver's other tests) using the Model 3, and the results it got are wholly consistent with, though still slightly short, of what you'd expect from the EPA highway numbers.

On whether the EPA Highway range predicted the range at steady speed, the CARWOW test, where they drove the speed limit (70 MPH) unless traffic dictated otherwise (or left to find a charger), indicates that they do. All the cars I looked at -- the Nissan Leaf, Jaguar I-Pace, and the Kia Niro -- all had real world ranges that exceeded the EPA Highway range by 2% to 22%. These same cars didn't perform this way on the Car and Driver test but (a) the Car and Driver test was done at 75 MPH; and (b) we have no idea what Car and Driver did, which is a problem in that Car and Driver doesn't seem to understand 32F will have a big impact on range and thinks that a 10 MPH wind won't have any impact on range (can't make this stuff up).

When you look at all the numbers it seems clear that: (1) the EPA Highway range accurately estimates steady speed freeway driving to a reasonable degree; and (2) range numbers for the the Model S may be wonky or Car and Driver may have had a wonky Model S.

 

[dbsb3233]

Unless you have found a way to enter your car and start your trip while the car was already moving 75 MPH, no real-world highway trip is actually steady state highway speed, so that's an artificially high standard to expect anyone to meet. I can drive at a 75 MPH cruise control speed on the highway, but since I got stuck at 2 traffic lights on my way to the highway, my actual average speed will be 68 or whatever.

I already explained this above. A mile to get back on the interstate and back off at the next charger takes like ONE MPH off the average. So 74 instead of 75. NOT 48.

48 is a helluva long way from 75.

 

[dbsb3233]

You are also overweighting the importance of the average speed. When you go 0-60 MPH your average speed is 30 MPH. When you go 60 MPH your average speed is 60 MPH. To cover the same ground would you use more energy going 0-60 MPH twice with an average speed of 30 MPH or just going 60 MPH?

Sorry, but I don't need to recharge after 5 seconds of going from 0-60. I need to recharge after going 200 miles at 75 MPH and maybe a mile or two at 30 getting on/off the interstate for chargers. That doesn't add up to a midpoint result (37.5 MPH avg) like you're suggesting, it adds up to about 74 MPH avg.

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