Aeromod nissan leaf improved aerodynamics increased range

VitaminJ said:

lorenfb said:

That was a good test, but please post the actual data without having the viewer remember the comparative
results from each run. It would be interesting to repeat the tests at 45 MPH for those of us not always
driving at freeway speeds. Thanks.

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Wow I thought I made that really easy by putting a popup that says "Skip to 10:12 for results." Here it is nice and easy for you:

After over a year and 20 pages of this thread, which you have been a part of from the very beginning expressing skepticism...after all that you can't even be arsed to watch the test video of the test you asked for. What a great sport you are! Instead of talking about the results of my 65mph test you ask "oh gee someone should do it at 45mph instead." People like that...

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So now you have to do an ad hominem attack and take the thread negative, right?

Anyway, hardly anything "to write home about", i.e. about a 6% change at 65 MPH, and that excludes
any sampling errors, e.g. data measurements & how well each speed run was maintained - your bias
in doing the test. The results at 45 MPH will be a total joke. So on average a Leaf owner might
experience a 2 -3% change in range (~ 2 miles increase in range).

Bottom line: Aero mods are a total waste of time for the typical Leaf owner!

lorenfb said:

So now you have to do an ad hominem attack and take the thread negative, right?

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I did not make any attack on you. I just pointed out that you have been a (negative) voice in this thread since the very beginning over 2 years ago, and when your wishes were delivered in the form of a 10 minute video, you couldn't be arsed to watch it but you got the negativity down pat! That's all true unless you care to offer evidence to the contrary.

Sorry, but I don't have much patience for people who want to be part of the conversation but offer nothing of substance.

Anyway, hardly anything "to write home about", i.e. about a 6% change at 65 MPH, and that excludes
any sampling errors, e.g. data measurements & how well each speed run was maintained - your bias in doing the test.

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See, this is why I made a video; so we wouldn't have to go back and forth 3 times. I made the mistake of thinking you'd watch the video so here we are going back and forth.

6% gain we both agree on now? Ok cool!

I used cruise control, set on the first run, and resumed on every subsequent run. The speed was held completely automated by the CC. You can see the CC being activated on each run in the video and the video shows that the speedo never changes from 65mph during any run.

The only bias being shown is yours, you haven't even taken a look at the evidence but you have already dissected it.

The results at 45 MPH will be a total joke. So on average a Leaf owner might
experience a 2 -3% change in range (~ 2 miles increase in range).

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This is just purely conjecture on your part. Do you have stats for the average Leaf driver? Maybe you should do the test at 45mph before you make any claims.

Personally, I drive 70 miles a day on a highway that goes in the middle of nowhere and there are usually 5 or 6 other Leafs I see on the same commute. We drive at speeds up to 80mph.

Bottom line: Aero mods are a total waste of time for the typical Leaf owner!

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Absolutely not. The mods will result in 0.2 mi/kwh increase in efficiency on a level, very bumpy road at 65mph. Decreased aerodynamic drag will also allow for increased regeneration under all circumstances, and more resistance to headwinds. +0.2mi/kwh will result in a gain of 4 miles over a 20kwh charge, and that gain will only increase with speed. Also on the very bumpy road I tested on, total drag from rolling resistance would be higher than on a smooth road, so therefore on smoother roads more aero benefit could be experienced. +0.2mi/kw will also allow the driver to use climate control with no penalty up to 0.2mi/kwh.

I have claimed it increased my driving efficiency by 12% or 0.5mi/kwh on my commute; well if we start with 0.2mi/kwh gain on level ground, add in increased regeneration on my 5000 vertical foot elevation change over the commute, a maximum speed of 80+mph, and also add in headwind resistance my 0.5 mi/kwh claim isn't a bridge too far.

The time you have spent in this thread vastly overshadows the 30 minutes it would take to install these mods, yet here you are! Your time was completely wasted! At least I can claim a 6% gain!

Laws of physics applies to all cars. Aerodynamic drag is more than 50% of the load on many cars at ~28MPH - and the Leaf is only a bot better than average.

Check this calculator:

http://ecomodder.com/forum/tool-aero-rolling-resistance.php

A helpful fellow on Youtube reminded me that I did my test at about 5,600ft above sea level. At the temperature of 50 deg F that night that puts the density altitude around 6000ft. Someone at sea level would experience maybe up to 20% better gains than I did simply because the air is denser at sea level. That would be very cool if someone at sea level tested the same procedure as I did.

Right - even barometric pressure and humidity affect the drag.

Here's a little factoid: humid air has lower drag than dryer air, all else being equal.

It's also worth noting that aero mods on an electric vehicle with regenerative braking should result in a bigger efficiency increase than on an ICE vehicle, because any air resistance slowing the vehicle down could have been converted into electricity. In essence, poor aerodynamics are a penalty paid twice by cars with regenerative braking.

I've done no scientific experiments, but this winter I taped off the grill with packing tape. Last winter I averaged about ~4.0 miles/kwh, this winter I've been closer to ~4.3 miles/kwh. I never use the heater (puffer and heated seats/steering wheel do the trick).

Last winter was slightly warmer.

kidjan said:

It's also worth noting that aero mods on an electric vehicle with regenerative braking should result in a bigger efficiency increase than on an ICE vehicle, because any air resistance slowing the vehicle down could have been converted into electricity. In essence, poor aerodynamics are a penalty paid twice by cars with regenerative braking.

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Lower drag also means better coasting, and coasting is the best use of the kinetic energy of the moving car. Regen is great for when you need to slow down, but coasting means you accelerate less in the first place, then use it better. Regen is icing on the cake.

kidjan said:

I've done no scientific experiments, but this winter I taped off the grill with packing tape. Last winter I averaged about ~4.0 miles/kwh, this winter I've been closer to ~4.3 miles/kwh. I never use the heater (puffer and heated seats/steering wheel do the trick).

Last winter was slightly warmer.

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While traveling on freeways (50% of driving) at 60 - 65 MPH in the past, my overall average was about 4.5 miles/kWh.
Presently, my freeway speeds are 50 - 52 MPH. My overall average is now 5.1 miles/kWh. That's about a 13% improvement
without any aero mods, and how simple was that!

lorenfb said:

While traveling on freeways (50% of driving) at 60 - 65 MPH in the past, my overall average was about 4.5 miles/kWh.
Presently, my freeway speeds are 50 - 52 MPH. My overall average is now 5.1 miles/kWh. That's about a 13% improvement
without any aero mods, and how simple was that!

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Imagine if you also had aero mods! It would be even better!

lorenfb said:

While traveling on freeways (50% of driving) at 60 - 65 MPH in the past, my overall average was about 4.5 miles/kWh.
Presently, my freeway speeds are 50 - 52 MPH. My overall average is now 5.1 miles/kWh. That's about a 13% improvement
without any aero mods, and how simple was that!

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Yes! The easiest "aeromod" is to simply reduce speed. If you drive at 12mph you'll be able to go very far.

But let's say you could reduce the aerodynamic drag to a coefficient of around 0.17Cd. The result would be that going 65mph you'd get the efficiency of going 45mph without aeromods.

With aeromods you also benefit if you use climate control because going faster you would use the climate control for less time.

The only thing I see in this thread, though, is that everyone seems to go about aeromodding backwards. The focus usually goes towards the front of the vehicle. Not that there isn't room for improvement in the front, but the main improvements to be made are in the rear of a vehicle.

As you can see, the distinctive tear drop shape can have a barely noticeable 0.05Cd going forwards or a terrible 0.34Cd going backwards. That's nearly 8 times the amount of air drag!

The few times I've seen cars put in a wind tunnel backwards, that's almost always when they are more aerodynamic. The Leaf is similar in design to other cars. The sloping part is in the front, and the blunt end is in the rear. Aerodynamically it should be the other way around. But we aren't going to be going down the highway backwards now are we. Others have overcome this by simply adding and airplane or boat tail to the rear of the vehicle. A classic example is the AeroCivic, which cut it's drag in half, and the biggest improvement wasn't the wheel spats or blocking off the front grill. It was the tail that was attached to it.

AeroCivic said:

The biggest one, both in strange looks received and on its effect in improving my gas mileage is the boat tail. This is the tapered back end of my car that resembles the back of an aircraft fuselage. This eliminates the recirculating, low-pressure eddy that forms behind "normal" cars and that act to slow them down. This eddy is also responsible for the dirt that accumulates on a car's backside and allows a closely following car to improve its mileage by drafting. As a result of my boat tail, the back end of my car remains clean and anybody drafting me would gain no mileage benefits.

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Brenthasty has a kammaback like that on his Leaf for a couple years now. Claims 50% improvement. His execution is the best I've seen, minimal material to create the most effect. It's also clear so it's as unobtrusive as possible. That's a little bit too much for me, I want the car to look as stock as possible and no major mods because I want to sell it in a couple years. His is the one to copy if you're game yourself.





More pictures at his blog:
http://fireplacefurnaces.blogspot.com/2016/03/aeromodding-nissan-leaf-increased-range.html?m=1

Brenthasty said:

http://ecomodder.com/forum/em-fuel-log.php?vehicleid=9542

Long term results are a 50% improvement!

This make a big difference on long road trips .
Reduces time spent at Quick Charge stations .
Reduces loss of battery capacity over time due to reduced sustained power draw from the traction pack.

Had you tried it a year ago you would already know....

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VitaminJ said:

Brenthasty has a kammaback like that on his Leaf for a couple years now...

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Thanks! That's awesome!

lorenfb said:

The energy consumed by a vehicle's drag resistance as it moves thru the air is:

Energy = K A V^2, where K is the coefficient of drag, A is the frontal area of the vehicle, V is the velocity (it's squared)
of the vehicle.

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Basically, but you forgot to add the density of air in the equation. Energy = V^2 Cd A D, where Cd is the coefficient of drag, A is the frontal area, V velocity and D is the density of air (or other fluid. Just think, when we get to travel to Mars we'll be able to drive Leaf's there. Or make it submersible and drive underwater??)

lorenfb said:

As can be noted from above, the vehicle's speed does affect both the rolling resistance energy loss and the drag
energy loss.

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That's not true. The power to combat rolling resistance increases with speed, but the amount of energy used per mile doesn't hardly increase. If it takes 16 miles per kilowatt-hour to push against rolling resistance at 5mph it will be basically the same at 80mph. Aerodynamic drag does use more energy per mile with greater speed. The amount of energy increases exponentially too. On most vehicles, the area where both use about the same about of energy per mile is around 25 to 30mph.



If you were to figure power to overcome aerodynamic drag you would use the same equation, only it would be V^3.

Power = = V^3 Cd A D.

http://ecomodder.com/forum/tool-aero-rolling-resistance.php

VitaminJ said:

Brenthasty has a kammaback like that on his Leaf for a couple years now. Claims 50% improvement. His execution is the best I've seen, minimal material to create the most effect. It's also clear so it's as unobtrusive as possible. That's a little bit too much for me, I want the car to look as stock as possible and no major mods because I want to sell it in a couple years. His is the one to copy if you're game yourself.

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I would love something like that which could be removed without damaging the car. Is there a post anywhere with either where to buy or instructions on how to make?

lorenfb said:

The energy consumed by a vehicle's drag resistance as it moves thru the air is:

Energy = K A V^2, where K is the coefficient of drag, A is the frontal area of the vehicle, V is the velocity (it's squared)
of the vehicle.

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Yes, it's (the equation) power and not energy (Energy = Integral (Power dt)) and V is cubed, i.e. my typos.

lorenfb said:

As can be noted from above, the vehicle's speed does affect both the rolling resistance energy loss and the drag
energy loss.

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The above statement is correct.

IssacZachary said:

The power to combat rolling resistance increases with speed,

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Yes, that's correct! The energy loss is; Integral (Power dt).

I found some old pictures of my older Honda that I aeromodded back in the day. If someone doesn't want to buy factory mudflaps you can get 99% of the same results with a simple tire airdam like this made from plastic sheet:

DesertSprings said:

I would love something like that which could be removed without damaging the car. Is there a post anywhere with either where to buy or instructions on how to make?

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I can only point you to his posts in this thread and the link to his blog that I shared.

wow the kammback that brenthasty did is very nice! i would not mind rocking one of those for bumping my freeway efficiency

estomax said:

wow the kammback that brenthasty did is very nice! i would not mind rocking one of those for bumping my freeway efficiency

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Yup, I'd love to get one.

That Kammback would sell well as an aftermarket Leaf accessory.