Efficiency on mostly flat highways

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ztev

Member
Joined
Dec 3, 2021
Messages
18
Question for those of you who primarily drive on mostly flat highways, like those found in most of the midwest: What's your average miles/kWh? So far I've driven my new car less than 200 miles, and am at 3.2/kWh average with mostly highway driving plus a bit of in-city driving. I've primarily been using the e-Pedal (because I like the experience) in D mode, with Eco on. Haven't really employed any particular efficiency-improving techniques yet, other than maybe anticipating stops a bit earlier.

Curious how my (seemingly low) 3.2/kWh stacks up against other midwesterners.
 
You don't want my data, but I will note that because it's Winter, and because ePedal is not the best choice for highway driving in Winter (that would be D + Eco), your numbers aren't that bad.
 
Inflate your tires to 40 psi and drive the speed limit, if you really want to improve efficiency. Also, on downhill stretches, you can coast in neutral.
 
For those with a spreadsheet handy, a nice graph is easy to cook up relating speed to consumption by using the EPA dyno 'set' coefficients in a best fit polynomial:

A: 11.75 Lbƒ
B: 0.1746 Lbƒ/mph
C: 0.01884 Lbƒ/mph^2

1 Lbƒ = 4.44822 N

https://dis.epa.gov/otaqpub/display_file.jsp?docid=52059&flag=1
Just be aware that adverse road conditions, wind or A/C usage is not considered, and terrain is flat
 
I have a bit of a lead foot, and prefer to cruise between 70-80mph. Yes, I'm aware those speeds are efficiency killers. Just curious how my numbers stack up against people with similar habits this time of year.
 
There's nothing wrong with your LEAF, this is 100% about your driving habits. Not being judgemental - enjoy driving with a lead foot, just realize that you control the efficiency and resultant range (ambient temperature and weather aside). If you don't need the extra range, have fun!
 
ztev said:
So far I've driven my new car less than 200 miles, and am at 3.2/kWh average with mostly highway driving plus a bit of in-city driving.
[edit]
I have a bit of a lead foot, and prefer to cruise between 70-80mph. Yes, I'm aware those speeds are efficiency killers. Just curious how my numbers stack up against people with similar habits this time of year.
Now I can properly answer your question: you get a good 1 m/kWh less than I do (even at highway speeds), but I tend to keep it around 60 mph. While the reduction gear oil change I did does fractionally boost my m/kWh (search the forum for a couple of good threads on this), I routinely see more than 4.5 m/kWh when not on the highway, so your "lead foot" is definitely costing you (fairly significant) range.
 
ztev said:
I have a bit of a lead foot, and prefer to cruise between 70-80mph. Yes, I'm aware those speeds are efficiency killers. Just curious how my numbers stack up against people with similar habits this time of year.

If you are using D mode, try driving the same way, but in Eco mode. You still get full power when you floor it, but you will probably use less power overall. Also, Eco limits the heater power, and thus will save substantial amounts of energy just doing that.
 
alozzy said:
If you don't need the extra range, have fun!
Amen to that, nothing more fun egging on Tesla drivers to a race when you can tell they are trying to drive economically. Same for other Leaf drivers. :lol: :twisted:
My wife says I'm such an ass to her when I come up on her Leaf while she is driving. She must always accept the challenge in her mind.
 
With tires a smidge above 40psi on a hot day, I have been able to show 4 miles/kWh with aftermarket light rims in our S+ at 70mph. Our SV+ with stock 17" rims sees low to mid 3s at 70mph in summer.

Winter is less, and depends on many variables including ambient temp, snow and battery temp. (Wind is always a factor)

https://youtu.be/MhxXQCVqsMk
 
Along these same lines, I see from the EPA testing that Teslas are consistently the most efficient EVs but I also know that many of us Leaf drivers get the same mileage, expressed in kWh/mile, that EPA gets on Teslas. Most of us on the Forum probably get a decent .25 for much of the year- do Teslas really outperform this? As an aside, I prefer the EPA (and Tesla) efficiency formula of kWh/mile to the Leaf formula of m/kWh. Similar to using R-value for insulation value as opposed to using U-value. The REAL cost of driving is not how many miles per gallon our ICE got but how many gallons it took to drive a mile. Going from 40 to 50 MPG translates to WAY less savings than going from 20 to 30 MPG, etc.
 
dmacarthur said:
do Teslas really outperform this?
If you have the same driver and same routes and same conditions -- sure.

I'm an efficient driver and usually manage about 200 Wh/mile in our LEAF but I don't drive it a lot so I would not take that as a 4 season average and it does not include inclement weather or highway driving. Over 44k miles of driving my Tesla Model 3 year round in every condition my lifetime was 220 Wh/mile but commuter drives in nice weather were usually around 180 Wh/mile.

The LEAF is efficient as a small city commuter but its high Cd rears its head on the highway. The unsung (on this forum) advantage for the Tesla when it comes to efficiency is the highway, and moderately aggressive driving style not having a big efficiency hit.

The other thing to know about the EPA figures is that the LEAF is tested with a 2-cycle protocol while the Tesla Model 3/Y use the 5-cycle protocol. This has the effect of the Tesla having an overstated summer efficiency while the LEAF has a *markedly* overstated winter efficiency. The EPA would do well to mandate 5 cycle testing for all cars, and to report each cycle on the window sticker so that people could match their driving to the test. In the meantime the EPA numbers are routinely misunderstood and misinterpreted.
 
On the subject of Speed, if you double the speed, air resistance goes up 4 times(and power consumption with it), and so forth, as I recall. Call it "Trolling" but I do like to point out to the "kids" (whether 16 or 60), that like the 0-60 "adrenaline rush"; that going 60-0 in a few milliseconds will result in a new "tint" for your windshield...very limited color option though.
 
https://insideevs.com/news/553907/ev-range-charging-tesla-rivals/?fbclid=IwAR2YcLLaQblrLL7xw9VVlqJnuMc1Rq9Jrj1zkvcZiuFwtkTxw5IKlSwNku0

Interesting side-by-side, Tesla again appears to be more efficient although they relied in on-board numbers rather than measuring actual usage (their concern was speed of charging, not amount of charging...). Why not, while you are at it, measure electrical usage to verify each car's on-board read-out?
 
I get very good efficiency but I drive within the speed limit, accelerate slowly and try to time red lights. That said, I'm amazed at how much power it takes to run all the infotainment and radars, etc on the higher tech cars now days. I have Leaf S so it has very minimal 'smarts' but it's all I need at this point. If I ever do get a car with all the self-driving tech I hope I have the option of turning it off to save power when desired.
 
It was not stated whether the Tesla was pre-conditioned but the numbers say no. If they had, the Tesla would have been the winner by far. Until the other EV manufacturers learn to pre-condition the pack before charging, there is no contest in these types of tests when the Tesla is driven as designed.

And it was 4C. On an actual cold day, the Tesla is that much further ahead.
 
It was not stated whether the Tesla was pre-conditioned

I THOUGHT that I heard the guy say that that the Tesla knew it was coming in for a charge and was therefore pre-conditioning, which would make sense given their connectedness.....
 
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