Sway concept hints at Leaf 2 styling ?

[fotajoye]

... can meet or exceed its current aero numbers and 0-60 times and can go an honest 200 miles at 65 mph in one charge.

All we hear is "double" the range. So, it won't go 200 miles @ 65 mph at 0 deg. F.

The problem with aero is the interior space. If you want nice headroom in the back, the aero will be hit. So, if they want Leaf to continue to be a family car (not those who go after aero & 0-60 times) - it is not going to have great aero.

One other option Nissan has is to make Leaf 2 appeal to people with minimal interior space needs but want "manly" things like an aggressive posture and fast 0-60. Then, bring on E-NV02 with the larger battery for families.

Nope! aerodynamic resistance is mainly a function of the car's frontal area, CD and the velocity of the air; has little to do with the configuration of the interior. Also, range as defined now is at best a relative number and it keeps changing as EPA tries to decide how to represent the numbers...MPGe...?...part of their dilemma is range depends on the performance of the traction battery at different temperatures. At 0 deg F, many chemistries are down at least 10% on capacity. Also range depends on how fast you drive...Tesla quotes their max range at 55 mph. Nissan clouds the issue even more by quoting Japanese range cycles and kilometers without disclosure...which to the ignorant sounds great until you buy one and take it out into the real world.
One thing you can safely bet on, the 200 mile range quoted by Nissan is optimistic.

 

[GRA]

... can meet or exceed its current aero numbers and 0-60 times and can go an honest 200 miles at 65 mph in one charge.

All we hear is "double" the range. So, it won't go 200 miles @ 65 mph at 0 deg. F.

The problem with aero is the interior space. If you want nice headroom in the back, the aero will be hit. So, if they want Leaf to continue to be a family car (not those who go after aero & 0-60 times) - it is not going to have great aero.

One other option Nissan has is to make Leaf 2 appeal to people with minimal interior space needs but want "manly" things like an aggressive posture and fast 0-60. Then, bring on E-NV02 with the larger battery for families.

Nope! aerodynamic resistance is mainly a function of the car's frontal area, CD and the velocity of the air; has little to do with the configuration of the interior.

He's not saying that the configuration of the _interior_ will affect the drag; he's saying that the shape of the roof line to minimize the drag will result in lower rear headroom, just as it does in the Tesla S.

Which design profile do you think will have lower drag due to the roofline, and which more rear headroom, AOTBE: a modern Jaguar sedan, with a smooth curvature down to a high trunk: http://images.thecarconnection.com/lrg/2015-jaguar-xj-4-door-sedan-xjl-supercharged-rwd-side-exterior-view_100486058_l.jpg" onclick="window.open(this.href);return false;

or a 1980 Jag, with an abrupt discontinuity and a low trunk? http://invimg1.autofunds.com/InventoryImages/2014/09/09/2028_566486_CFS3_12041570_5471909472014.jpg" onclick="window.open(this.href);return false;

Compare the modern Jag to the Tesla S: http://www.blogcdn.com/www.autoblog.com/media/2012/09/05-2012-tesla-model-s-fd-1347336754.jpg" onclick="window.open(this.href);return false;

There's a reason the Prius and Insight look so much alike; there's only so many ways to reduce turbulence (-> drag) at the rear end of the car. Same goes for a sedan-style body, which is why cars designed for minimum aero resemble each other so much.

 

[fotajoye]

Which design profile do you think will have lower drag due to the roofline, and which more rear headroom, AOTBE: a modern Jaguar sedan, with a smooth curvature down to a high trunk: http://images.thecarconnection.com/lrg/2015-jaguar-xj-4-door-sedan-xjl-supercharged-rwd-side-exterior-view_100486058_l.jpg" onclick="window.open(this.href);return false;

or a 1980 Jag, with an abrupt discontinuity and a low trunk? http://invimg1.autofunds.com/InventoryImages/2014/09/09/2028_566486_CFS3_12041570_5471909472014.jpg" onclick="window.open(this.href);return false;

Compare the modern Jag to the Tesla S: http://www.blogcdn.com/www.autoblog.com/media/2012/09/05-2012-tesla-model-s-fd-1347336754.jpg" onclick="window.open(this.href);return false;

There's a reason the Prius and Insight look so much alike; there's only so many ways to reduce turbulence (-> drag) at the rear end of the car. Same goes for a sedan-style body, which is why cars designed for minimum aero resemble each other so much.

I know that. And, the amount and configuration of the interior space is one of the compromises to a street car's aerodynamics that dictates the shape of the roof, etc. The Tesla has a CD of .24 and the Leaf a CD of .28-.29. The difference is hardly worth the inconvenience. We are talking practical street cars here not expensive toys for the rich. If you want to introduce that bag, that a different segment altogether and I'll be glad to discuss and debate aerodynamic and airflow physics as I have racing and engineering knowledge of the subject; but, that's not what this thread is about. This thread is about: Leaf 2: What We Know.

 

[evnow]

Nope!

GRA's explanation is spot on.

I should also note that long range and low aero are opposing demands. For example, in the current Leaf they can take out some battery and lower the rear seats and thus the roofline to get better aero. When we are talking about compact cars, volume of the battery matters as much as the cost.

Nissan clouds the issue even more by quoting Japanese range cycles and kilometers without disclosure...which to the ignorant sounds great until you buy one and take it out into the real world.
One thing you can safely bet on, the 200 mile range quoted by Nissan is optimistic.

Nissan doesn't use kilometers and NEDC or the Japanese cycle when talking to US press (in US). I don't expect them to use EPA numbers when talking in Japan.

This is the reason "double range" is a good indicator. You can use whatever cycle or scenario you want to get approximate range of next gen Leaf, if you know current Leaf's range.

 

[dhanson865]

.....snip.............
"Kia tells us that the Soul EV will only be available in California, Oregon, New York, New Jersey and Maryland."

So for those of us in the other 45 US states the Soul EV doesn't exist as competition.

Though I hear they are selling it all over Canada, and parts of Europe. .......snip........

Kia is not saying they WON'T sell the soul ev in all 50 ... just not yet. It does take a bit to get techs up to speed. I will say this for Kia ... They're supporting Chademo 100kW systems in the EU. I don't see Nissan doing that. But with a puny Leaf battery (even NEW ... much less once it's lost 20% capacity) why on earth would Nissan support bigger charge power.

No they say they will expand the list of states sometime in the next month but we don't know if that will be 10 states or what. I seriously doubt it will be 50 states because of this:

they've sold 117 in two months and then they say that they were surprised at the unexpected demand.

http://www.greencarreports.com/news/1097078_kia-soul-ev-a-big-hit-in-ca-sales-to-expand-sooner-than-planned" onclick="window.open(this.href);return false;

Kia American vice president of product planning Orth Hedrick said in a recent interview with Autoblog Green.

He said customer interest in the Soul EV was significantly greater than Kia had originally anticipated, saying officials were "kind of shocked" by how well it was received.

117 in two months is unexpected demand for a car with more range than a Leaf that sells thousands in that time span? Until it is beating 500 a month it's still a joke to me. Obviously just compliance fodder.

Top 4 in that list aren't just compliance cars. But only the top 2 are true EVs with another 1 and half cars for honorable mentions.

Tesla Model S - solid range, and they'll sell it in any state they can, even going to court to add more states. It's just out of my price range even as a used car.

Nissan Leaf - poor range but large volume of sales, available in all 50 states I do believe. Great value right now on the used market for those of us with a short commute.

BMW i3 (not a true EV, but it only has a 1.9 gallon gas tank so I'll call that a primarily EV hybrid). Unfortunately it isn't sold in more than a handful of states but it is at least selling in volume.

Chevy Volt - uggh another PHEV and this time sporting a 9.3 gallon tank so the design doesn't even speak to the primarily EV mode most drivers end up using after they buy it. At least it can be a true EV if you have a short enough commute and they'll sell it to you if you want it. If you sold me a new one for $10,000 I'd drive it because as an EV it has about the same range as a Leaf that's lost a few bars and then you could keep a couple of gallons in the tank for emergency use. I wouldn't buy one that is out of warranty though. Repair history is worse than a Leaf.

Ford Fusion energi and c-max energi have a 14 gallon gas tank. Why bother calling it a plug in if you are going to design it with a full sized gas tank? I can barely get 8 gallons in my 2005 Prius. Anything with a tank bigger than that is a step backwards. Are these sold nation wide? I hope they are just compliance cars.

Totota Plug in Prius unfortunately is of the same damaged mindset. 11.6 gallon gas tank and they barely sell them. I'd love to drive one but I won't pay two to three times the cost of a used leaf to get a used PiP. Clearly priced as a compliance car for primary use by Californians.

anything below that on the list doesn't sell enough to even have a new market let alone a used market.

So yes, pleas Kia start selling the Soul EV in more states. Get up to the leaf levels ASAP and give us a real choice other than Nissan for something that costs less than $35,000 and doesn't have a gas tank.

 

[TimLee]

...
Ford Fusion energi and c-max energi have a 14 gallon gas tank. Why bother calling it a plug in if you are going to design it with a full sized gas tank? I can barely get 8 gallons in my 2005 Prius. Anything with a tank bigger than that is a step backwards. ...

Although completely off topic unless Nissan decides to offer gasoline range extender option for the Gen 2 LEAF:
I do not understand what is so bad about a large gasoline tank on a range extended electric vehicle?
As long as you haven't adversely impacted space utilization or aerodynamics, the efficiency impact of a larger gas tank that is only filled when being used for a long range trip is pretty small.
Why make the vehicles use for a long range trip less convenient by putting a tiny gas tank on it :?:

I agree that doing the range extension with a small diesel would be more efficient than gas although more costly up front.
But whether gas or diesel the range with the range extender should still be what is pragmatic.
With diesel pragmatic might be 700 mile range like the Passat TDI.

 

[fotajoye]

Nope!

GRA's...

I should also note that long range and low aero are opposing demands. For example, in the current Leaf they can take out some battery and lower the rear seats and thus the roofline to get better aero. When we are talking about compact cars, volume of the battery matters as much as the cost.

Nissan clouds the issue even more by quoting Japanese range cycles and kilometers without disclosure...which to the ignorant sounds great until you buy one and take it out into the real world.
One thing you can safely bet on, the 200 mile range quoted by Nissan is optimistic.

Nissan doesn't use kilometers and NEDC or the Japanese cycle when talking to US press (in US). I don't expect them to use EPA numbers when talking in Japan.

This is the reason "double range" is a good indicator. You can use whatever cycle or scenario you want to get approximate range of next gen Leaf, if you know current Leaf's range.

I guess it's OK to go into this since you are the moderator:
Here is a list of just some of the things an engineer can change to improve an EV's aerodynamics:
Round the edges of the front end
Tune the grille and fascia openings
Tune the wheel openings
Place small spoilers in front of the tires to reduce turbulence
Tune the size and shape of the outside mirrors and their attachment arms
Install cameras instead of side view mirrors
Reshape the water channel on the A-pillars
Adjust the front fascia and air dam to reduce drag under the vehicle
Add side skirts
Tune the deck height, length and edge radius
Install a rear spoiler
Adjust the angle of the rear window
Use a diffuser to tune air coming off the underside
Install "belly pans," underbody panels that cover components and smooth airflow
Install air dams that drop lower at higher speeds
Install rear spoilers that pop up to reduce lift at higher speeds
Lower the vehicle at speed

Like airplanes, pinching in the roof line and sides to help maintain a gradual decrease in the surface as it goes to the back of the car will assist in keeping the boundary layer close to the surface and from burbling off disruptively. And, If you look carefully, you will see that is done on the Leaf to a small extent already. In fact an ideal aerodynamic shape for a car is a tear drop with a Cd of about .05 and one of the worse is a flat panel fully into the air flow with a Cd of about 1.25. Unfortunately, cars must be practical devices so there are compromises and that's why the great attempts to reduce the aerodynamic drag. As I have stated before the Cd of the Tesla S is about .24 and a Leaf is .28. The formula for aerodynamic drag is AD=F*Cd*D*V squared; where F is the car's frontal area; Cd is the car's drag coefficient as defined by the car maker; D is the air density; and V is the car's velocity squared. Since the velocity is a square function, it has a great effect on drag, If you double a car's speed, for example; from 35 mph to 70 mph, the drag will increase four times. While the speed has a great effect, the 14% difference between a Leaf and a Tesla's Cd(.04) would make little difference.

Here is a nice explanation of aero for gassers:
http://www.edmunds.com/fuel-economy/improving-aerodynamics-to-boost-fuel-economy.html" onclick="window.open(this.href);return false;

At this point of the Leaf's development; removing some of the battery cells to lower the seat only makes sense if you don't want a full range battery. I'll take the range.

And lastly, Nissan did quote figures based on NEDC in kM/hr to everyone including the press when the Leaf was introduced; I take your word they don't do this to press people now. It will be interesting to see if there is a significant difference between what they announce and what one gets in range with the next generation Leaf. An honest 200 mile range figure would be most welcomed.

 

[fotajoye]

...
Ford Fusion energi and c-max energi have a 14 gallon gas tank. Why bother calling it a plug in if you are going to design it with a full sized gas tank? I can barely get 8 gallons in my 2005 Prius. Anything with a tank bigger than that is a step backwards. ...

Although completely off topic unless Nissan decides to offer gasoline range extender option for the Gen 2 LEAF:
I do not understand what is so bad about a large gasoline tank on a range extended electric vehicle?
As long as you haven't adversely impacted space utilization or aerodynamics, the efficiency impact of a larger gas tank that is only filled when being used for a long range trip is pretty small.
Why make the vehicles use for a long range trip less convenient by putting a tiny gas tank on it :?:

I agree that doing the range extension with a small diesel would be more efficient than gas although more costly up front.
But whether gas or diesel the range with the range extender should still be what is pragmatic.
With diesel pragmatic might be 700 mile range like the Passat TDI.

Seems OK with the moderator to go off topic:
What is so bad is the car makers don't have a low-cost, light weight, long range traction battery to offer users at this point; rarely would an internal combustion extender be needed if the EV had a 300 mile range and could utilize a quick charge network for longer distances. It's too bad, the answer to longer ranges are a Hydrogen Fuel Cell car, a super heavy battery, 1,200 lbs, as in the Tesla; an ICE extender, as in the i3 or the multitude of Hybrids that must carry around the additional weight of a full-size gasser engine and it's accessories.

 

[LEAFguy]

I sure hope the stupid honking Instrument Cluster doesn't make it into Leaf Gen 2 production. Its ridiculous and huge. Its almost an insult to even consider such as thing; too reminiscent of an ICE gasmobile. After giving us Leaf drivers a super-clean and efficient LCD screen that we have now, they would dare downgrade us to this relic of a monstrosity? What the heck. I don't mind the exterior; it actually looks sleek, somewhat futuristic, a little aggressive, and high quality. But, they failed on the interior (at least to me). Hopefully they gut this and think clearly when they send it to production.

This lousy archaic instrument cluster, exhaust pipes, ICE-style Drive Mode selector, and the ridiculously unnecessary grille would rule out the Gen 2 Leaf for me if it looked like this, straight away! I can't understand why they'd ruin their Leaf after so much time and innovation through R&D?

I won't go back to lousy and archaic ICE vehicle characteristics. No way!

Keep in mind that this is not actually LEAF 2.0 - this is a European small hatchback concept. Obviously, the LEAF will not have a grille (though faux is a possibility, hiding the charge port), and there will be no exhaust (dual or otherwise).

Also, regarding your comments on the interior design - concepts always get crazy with this stuff. Look for an evolutionary change to the current LEAF instrument panel, although I would really like to see something like this on the outside. Bold, yet stylish. They would tone it down a bit, but hopefully not too much.

Ghosn is already on record as stating twice the current range - 84 times two is 168. Not the 200 we're looking for, but enough to get many to say yes.

 

[NeilBlanchard]

Having a low Cd is the best way to extend the range for any given battery pack capacity. So, having a lower Cd means a longer range with an smaller pack; which means a lower price.

So, I hope they go in the direction of the Renault Eolab concept; which I think looks even better than the Sway concept.

 

[fotajoye]

Having a low Cd is the best way to extend the range for any given battery pack capacity. So, having a lower Cd means a longer range with an smaller pack; which means a lower price.

So, I hope they go in the direction of the Renault Eolab concept; which I think looks even better than the Sway concept.

The Cd has more of an effect on range at the higher speeds because of the square factor of the velocity; At 35 mph and below, it is almost negligible; even at 50 mph it is fairly minor. Also, a Cd of .28, which is what the Leaf has, is very good for a street car; Tesla's Cd is only .04 better, very minor. However, one improvement, that is estimated to improve range on any car by about 3% at speeds, is to replace the sideview mirrors with cameras.

Want to improve range? reduce the weight like BMW has on the i3 which weighs about 2,700 lbs which is about 500 lbs less than the Leaf. Another major factor, other than a higher battery energy density, is friction and the major device in friction is the tires which Nissan has already addressed with low rolling resistance tires. Some additional work can be done in the area of friction by eliminating the differential gearing and and the reduction gears and installing two smaller computer controlled and synchronized drive motors instead. Additionally lower friction lubricants can be used on all bearing surfaces.

There is also work proceeding to increase the efficiency and reduce the weight of the electronic devices: The first one that comes to my mind is to replace the Leaf's lead battery with a smaller, lighter Lithium battery. One reads a lot of about Lab work to reduce the heat losses, the size and weight of the Motor Control Unit, DC to Dc Inverter and on-board AC Charger by moving over to graphene devices. Hopefully one day this will be in mass production.

BTW, the AC Charger doesn't need to be on board the car. If one charges at home and uses quick charging stations for distance travels, you never use the AC Charger. You can hang it on the wall at home or use a small DC quick charger at home. Think about it. That's what racers do...saves weight and simplifies the design. And, if you just need to feel psychologically safe, you can build up a small AC trickle charger with a rectifier for comfort.

 

[DanCar]

Having a low Cd is the best way to extend the range for any given battery pack capacity....

Agree! Call me boring, but skip the muscular look of the sway concept and give me the prius egg look.

 

[hill]

.....snip.............
"Kia tells us that the Soul EV will only be available in California, Oregon, New York, New Jersey and Maryland."

So for those of us in the other 45 US states the Soul EV doesn't exist as competition.

Though I hear they are selling it all over Canada, and parts of Europe. .......snip........

Kia is not saying they WON'T sell the soul ev in all 50 ... just not yet. It does take a bit to get techs up to speed. I will say this for Kia ... They're supporting Chademo 100kW systems in the EU. I don't see Nissan doing that. But with a puny Leaf battery (even NEW ... much less once it's lost 20% capacity) why on earth would Nissan support bigger charge power.

No they say they will expand the list of states sometime in the next month but we don't know if that will be 10 states or what. I seriously doubt it will be 50 states because of this: . . . . . . . . snip . . . . .

That's fine to doubt. Ironically though, the mentioning of how dealers were surprised about "demand". I've never seen a big inventory of Soul EV's on the Kia Lots - maybe one or two. And in that same vein, you find auto sites claiming the plug-in-Prius is the "Best Selling Car". All that means in the authors' twisted way of looking at it is that they only sell 'em in a hand full of states ... and relatively low manufacturing quantities get bought up ... so they don't sit on the lot very long. Big deal. Perhaps the reason Kia Soul Dealerships are surprised simply means, "wow!! we sold both of the ones we got!!". That kind of data twisting is really meaningless. If/when Kia bumps up production and sales wow the dealerships ... then it means something.

That Soul EV's are being bought up means folks want more range. Only getting more range (with a still decent price) will keep the Leaf ahead of the Soul EV if/when they sell in more & more states.
.

 

[GRA]

Having a low Cd is the best way to extend the range for any given battery pack capacity. So, having a lower Cd means a longer range with an smaller pack; which means a lower price.

So, I hope they go in the direction of the Renault Eolab concept; which I think looks even better than the Sway concept.

The Cd has more of an effect on range at the higher speeds because of the square factor of the velocity; At 35 mph and below, it is almost negligible; even at 50 mph it is fairly minor. Also, a Cd of .28, which is what the Leaf has, is very good for a street car; Tesla's Cd is only .04 better, very minor. However, one improvement, that is estimated to improve range on any car by about 3% at speeds, is to replace the sideview mirrors with cameras.

The thing is, you need the long range at high speed, not when trolling around town. Around town it's fine to have the Cd of a Hummer, because you're unlikely to drive far enough to reach your max range, and you benefit from regen. At freeway speeds that's not the case, and any BEV that is presented as a complete replacement for an ICE has to have the range where it matters. All but three states west of the Mississippi [Edit: should read 'Missouri'] have rural interstate speed limits of 75 or 80 mph, and most people drive about 5 mph over that. Even at 70 mph that .04 increase in Cd is going to make a significant difference in freeway range, far more than the extra weight of the battery decreases it (as you mentioned below).

Want to improve range? reduce the weight like BMW has on the i3 which weighs about 2,700 lbs which is about 500 lbs less than the Leaf. Another major factor, other than a higher battery energy density, is friction and the major device in friction is the tires which Nissan has already addressed with low rolling resistance tires. Some additional work can be done in the area of friction by eliminating the differential gearing and and the reduction gears and installing two smaller computer controlled and synchronized drive motors instead. Additionally lower friction lubricants can be used on all bearing surfaces.

 

[GRA]

Which design profile do you think will have lower drag due to the roofline, and which more rear headroom, AOTBE: a modern Jaguar sedan, with a smooth curvature down to a high trunk: http://images.thecarconnection.com/lrg/2015-jaguar-xj-4-door-sedan-xjl-supercharged-rwd-side-exterior-view_100486058_l.jpg" onclick="window.open(this.href);return false;

or a 1980 Jag, with an abrupt discontinuity and a low trunk? http://invimg1.autofunds.com/InventoryImages/2014/09/09/2028_566486_CFS3_12041570_5471909472014.jpg" onclick="window.open(this.href);return false;

Compare the modern Jag to the Tesla S: http://www.blogcdn.com/www.autoblog.com/media/2012/09/05-2012-tesla-model-s-fd-1347336754.jpg" onclick="window.open(this.href);return false;

There's a reason the Prius and Insight look so much alike; there's only so many ways to reduce turbulence (-> drag) at the rear end of the car. Same goes for a sedan-style body, which is why cars designed for minimum aero resemble each other so much.

I know that. And, the amount and configuration of the interior space is one of the compromises to a street car's aerodynamics that dictates the shape of the roof, etc. The Tesla has a CD of .24 and the Leaf a CD of .28-.29. The difference is hardly worth the inconvenience. We are talking practical street cars here not expensive toys for the rich. If you want to introduce that bag, that a different segment altogether and I'll be glad to discuss and debate aerodynamic and airflow physics as I have racing and engineering knowledge of the subject; but, that's not what this thread is about. This thread is about: Leaf 2: What We Know.

Okay, you've lost me. ISTM that you are agreeing with evnow (and me), so why the objection to his post?

Edit: Here's an article re the Model S and its drag reduction during development, which was initially 0.32, then reduced to 0.27 and finally to the current value of 0.24:

Digital Wind Tunnel Video Shows Aerodynamics Of Tesla Model S

http://insideevs.com/digital-wind-tunnel-video-shows-aerodynamics-tesla-model-s/" onclick="window.open(this.href);return false;

 

[NeilBlanchard]

Having a low Cd is the best way to extend the range for any given battery pack capacity. So, having a lower Cd means a longer range with an smaller pack; which means a lower price.

So, I hope they go in the direction of the Renault Eolab concept; which I think looks even better than the Sway concept.

The Cd has more of an effect on range at the higher speeds because of the square factor of the velocity; At 35 mph and below, it is almost negligible; even at 50 mph it is fairly minor.

Aero drag contributes ~50% of the load on the drivetrain at ~30MPH. It is the majority of the load; the opposite of negligible. At 55MPH, it is ~75% of the load, and it goes to almost 90% at 75MPH.

A Cd drop of 0.04 is significant.

Oh, and the Leaf was measured by Car & Driver to be 0.32; while confirming the Cd of the Tesla Model S is 0.24. http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test

The Tesla Model S is TIED with the gen 3 Prius for CdA. Think about that for a minute.

 

[Graffi]

https://autos.yahoo.com/news/2017-nissan-leaf-know-far-electric-car-152249117.html" onclick="window.open(this.href);return false;

Saw this on Yahoo a few minutes ago.

 

[evnow]

https://autos.yahoo.com/news/2017-nissan-leaf-know-far-electric-car-152249117.html

Saw this on Yahoo a few minutes ago.

This is a reprint of the poor GCR article.

 

[fotajoye]

Aero drag contributes ~50% of the load on the drivetrain at ~30MPH. It is the majority of the load; the opposite of negligible. At 55MPH, it is ~75% of the load, and it goes to almost 90% at 75MPH.

A Cd drop of 0.04 is significant.

Oh, and the Leaf was measured by Car & Driver to be 0.32; while confirming the Cd of the Tesla Model S is 0.24. http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test....

Aerodynamic load is 50% at 30 mph; that's interesting; where did you find that? Also, the Leaf Cd is quoted in Nissan literature as .28-.29. Perhaps the cover article you read is in error. A truth often quoted is the aerodynamic drag is it's 4 times higher at 70 mph than at 35 mph; I believe that; but, I doubt the 50% figure; seems to me that figure would be specific to a particular car because of the other load variables. Here again velocity is the big factor in the calculations and I agree a .04 Cd is significant at 100 mph and would be a major concern at 200 mph on the salt flats.

 

[GRA]

Aero drag contributes ~50% of the load on the drivetrain at ~30MPH. It is the majority of the load; the opposite of negligible. At 55MPH, it is ~75% of the load, and it goes to almost 90% at 75MPH.

A Cd drop of 0.04 is significant.

Oh, and the Leaf was measured by Car & Driver to be 0.32; while confirming the Cd of the Tesla Model S is 0.24. http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test....

Aerodynamic load is 50% at 30 mph; that's interesting; where did you find that? Also, the Leaf Cd is quoted in Nissan literature as .28-.29. Perhaps the cover article you read is in error. A truth often quoted is the aerodynamic drag is it's 4 times higher at 70 mph than at 35 mph; I believe that; but, I doubt the 50% figure; seems to me that figure would be specific to a particular car because of the other load variables. Here again velocity is the big factor in the calculations and I agree a .04 Cd is significant at 100 mph and would be a major concern at 200 mph on the salt flats.

As the C&D article mentions, Cd will vary depending on which wind tunnel its tested in, which is why manufacturers only trust their own measurements of it. In this case, C&D tested all the cars in the same tunnel, so there was no variation due to the tunnel.

As to aero drag being 50% @ 30 mph, obviously it varies from car to car, but the power crossover point (where it takes more power to overcome drag than Rr) is usually in the 30-40 mph range. You can also see that the power required due to drag scales as the cube of the speed, not the square: 100 mph/70 mph is about 1.43, and the cube of that is just about 3, which matches up with the 42 hp required for the Model S @ 100 mph versus the 14 required @ 70, and the LEAF's 53 hp vs. 18 hp ditto.

What the C&D tests show is that the Model S (air suspension) only needs about 78% of the power (14 hp or 10.44 kW, versus 18hp or 13.43kW) as the LEAF does @ 70 mph to overcome drag. Rolling resistance isn't measured by these tests, obviously, and I'd expect the LEAF to come out ahead there given its much lighter weight etc.

Considering only the drag component, assuming you could use all of a LEAF battery's 24 kWh you could drive about 1.78 hours at a constant 70 mph; the Tesla S 85 could do that for about 8.1 hours. This is a ratio of about 4.55, while the difference in the battery capacity of the two cars is a ratio of only 3.54, giving the Model S a bonus of about 28.5% range compared to if it needed the same power to overcome drag as the LEAF. Usable battery capacity is less, obviously, but the relative rate at which you discharge the battery affects its capacity (higher rate = lower capacity), which would, by itself, give the Tesla with its much larger pack more usable capacity for any given total capacity at the same actual (not relative) rate of discharge, let alone a lower one. If that's clear as mud, put it this way: the LEAF, at 13.43 kW, has a relative rate @ 70 mph of C/1.78 (higher), while the Tesla has a relative rate of C/8.1 (lower).