edatoakrun
Posts: 5222
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: LEAF 2018 151 Mile Range Mystery

Sat Jan 27, 2018 8:03 pm

Will someone please try to explain to "SageBrush" (and others) how the EPA range and efficiency numbers are actually determined?

Maybe that will solve this great mystery...

SageBrush wrote:...The combined EPA city/highway efficiency result for both the 30 kWh and 40 kWh models is 301 Wh per mile.
In your preferred units, 3.32 miles per kWh...

The EPA does its testing as follows:
The car is charged to full;
Driven on the test cycles until it stops;
then the kWh at the meter to charge it to full is measured.
The distance driven divided by the energy (kWh) at the meter consumed, multiplied by 33.7 gives the MPGe...

See MY 2017 LEAF application for EPA certification, city and highway cycle range and kWh recharge accepted:

Recharge Event Energy (kiloWatt-hours) 31.7807
Charge Depleting Range (Actual miles) 166.41

Recharge Event Energy (kiloWatt-hours) 31.7807
Charge Depleting Range (Actual miles) 136.408

https://iaspub.epa.gov/otaqpub/display_ ... 806&flag=1
no condition is permanent

SageBrush
Posts: 2910
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: LEAF 2018 151 Mile Range Mystery

Sun Jan 28, 2018 7:46 am

The interesting point here is that Nissan added unlabeled and unpromoted kWh capacity in order to reach a range target for marketing reasons. Perhaps it is related to anticipated distance between QC stations. If they had continued their old ways, the 40 kWh Model would have had about 38 kWh usable and a range of 38*107/28 ~ 145 miles. As it stands usable is quite close to 40 kWh.

Personally, I would have preferred that they kept the extra kWh (and more) in reserve to be used for degradation. The 150 mile range is likely to drop to ~ 120 miles for US consumers overall in 3 years if the battery follows its brethren. Not that I put it past Nissan to build an even POORER pack in terms of degradation.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

powersurge
Posts: 1120
Joined: Wed Oct 21, 2015 10:24 am
Delivery Date: 06 Dec 2014
Location: Long Island, NY

Re: LEAF 2018 151 Mile Range Mystery

Tue Jan 30, 2018 6:01 am

Again, all EPA, Nissan, or "expert" range estimates are advertising numbers for uninformed people to "estimate" the capability of a car. We are Leaf owners and are the REAL experts who use and know the car daily... So those EPA estimates can go out the window in my view. Range of the Leaf and battery capacities are only physics, and do not change just because there are different model years. All that regeneration stuff from one pedal driving may be nice, but would not affect range more than about 5% max.

As I mentioned in a previous post, The advertised ranges give numbers (in miles) of range..... This is Assuming that the battery is worn down to 0% capacity... Which would be abusing the battery with every use... Not Real World..

My estimate of the range, with our knowledge of the Leaf is.. From 40 KWHs, the battery would only have about 37KWH available for use for driving range. If you always recharge at the low end of safety (20% charge), then you only have (37kwh X 0.80) 29.6 KWH for driving use. (I usually charge between 35-40% max.)

So, driving conservatively (4.0-4.5 miles/ KW) you would REALISTICALLY get 118.4 - 133.2 miles of COMFORTABLE range... Also, this estimate would be even more REALISTIC with the Leaf having a larger motor, which people would love to push harder, using more KWHs. I am happy with that mileage range, however, I may wait for the 60 KWH Leaf. You may not agree with my "professional scientific analysis", but If I am right (as we will see when the 2018 Leafs come out), then you guys owe me a cup of coffee.. :P

SageBrush
Posts: 2910
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: LEAF 2018 151 Mile Range Mystery

Tue Jan 30, 2018 7:25 am

@powersurge,

You are completely missing the point of this thread.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

wwhitney
Posts: 741
Joined: Sat Jul 17, 2010 10:10 am
Delivery Date: 01 Apr 2011
Location: Berkeley, CA

Re: LEAF 2018 151 Mile Range Mystery

Tue Jan 30, 2018 7:36 am

SageBrush wrote:The EPA range calculation is IIRC based on 55% city, 45% highway driving.
Since the LEAF 2018 is within 1 MPGe in both city and highway and has the same combined MPGe compared to the 30 kWh Model from 2017,

And the 30 kWh LEAF is rated at 107 miles EPA range,
We should expect the 40 kWh Model to have (4/3)*107 = 142.6 miles of range, yet it is rated for 151 miles.
The extra 8.4 miles is close to 3 kWh.

You are correct that if the MPGe is basically the same for the two cars, there is an apparent discrepancy between the ratio of the EPA ranges (151/107 = 1.41) and the ratio of the nominal capacities (40/30 = 1.33). However, there are a couple explanations that you haven't considered (or perhaps I missed them in this thread):

1) The usable battery capacity of the vehicle is not the same as the nominal capacity. So if the 30 kWh vehicle has 27 kWh usable, the ratio of 1.41 would mean that the 40 kWh vehicle has 38 kWh usable.

2) While less likely, since MPGe is based on wall to wheels, there could be an effect based on charger efficiency. E.g. the 2018 could be more aerodynamic (higher mi/kWh at the battery level) but have a less efficient charger (make the MPGe the same).

Cheers, Wayne

SageBrush
Posts: 2910
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: LEAF 2018 151 Mile Range Mystery

Tue Jan 30, 2018 9:39 am

wwhitney wrote:
SageBrush wrote:The EPA range calculation is IIRC based on 55% city, 45% highway driving.
Since the LEAF 2018 is within 1 MPGe in both city and highway and has the same combined MPGe compared to the 30 kWh Model from 2017,

And the 30 kWh LEAF is rated at 107 miles EPA range,
We should expect the 40 kWh Model to have (4/3)*107 = 142.6 miles of range, yet it is rated for 151 miles.
The extra 8.4 miles is close to 3 kWh.

You are correct that if the MPGe is basically the same for the two cars, there is an apparent discrepancy between the ratio of the EPA ranges (151/107 = 1.41) and the ratio of the nominal capacities (40/30 = 1.33). However, there are a couple explanations that you haven't considered (or perhaps I missed them in this thread):

1) The usable battery capacity of the vehicle is not the same as the nominal capacity. So if the 30 kWh vehicle has 27 kWh usable, the ratio of 1.41 would mean that the 40 kWh vehicle has 38 kWh usable.

Cheers, Wayne

This is my conclusion as well: the ratio between the models of usable capacity is wider than the model label implies.
My arithmetic is 3 posts earlier.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

powersurge
Posts: 1120
Joined: Wed Oct 21, 2015 10:24 am
Delivery Date: 06 Dec 2014
Location: Long Island, NY

Re: LEAF 2018 151 Mile Range Mystery

Tue Jan 30, 2018 9:43 am

SageBrush wrote:@powersurge,

You are completely missing the point of this thread.


OK, I will back out of this. You can continue comparing EPA specs....

User avatar
Nubo
Posts: 4940
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: LEAF 2018 151 Mile Range Mystery

Tue Jan 30, 2018 11:11 am

powersurge wrote:...As I mentioned in a previous post, The advertised ranges give numbers (in miles) of range..... This is Assuming that the battery is worn down to 0% capacity... Which would be abusing the battery with every use... Not Real World...


It's meant to allow comparisons, not to describe "real world" use-cases. An ICE should not be run down to empty on a regular basis either, FWIW.
I noticed you're still working with polymers.

powersurge
Posts: 1120
Joined: Wed Oct 21, 2015 10:24 am
Delivery Date: 06 Dec 2014
Location: Long Island, NY

Re: LEAF 2018 151 Mile Range Mystery

Tue Jan 30, 2018 11:42 am

Nubo wrote:
powersurge wrote:...As I mentioned in a previous post, The advertised ranges give numbers (in miles) of range..... This is Assuming that the battery is worn down to 0% capacity... Which would be abusing the battery with every use... Not Real World...


It's meant to allow comparisons, not to describe "real world" use-cases. An ICE should not be run down to empty on a regular basis either, FWIW.


OK I will stop...

wwhitney
Posts: 741
Joined: Sat Jul 17, 2010 10:10 am
Delivery Date: 01 Apr 2011
Location: Berkeley, CA

Re: LEAF 2018 151 Mile Range Mystery

Tue Jan 30, 2018 12:16 pm

SageBrush wrote:This is my conclusion as well: the ratio between the models of usable capacity is wider than the model label implies.

Well, I do point out an alternative possible explanation, but I agree the above statement is more likely.

However, you earlier said "the interesting point here is that Nissan added unlabeled and unpromoted kWh capacity in order to reach a range target for marketing reasons." That statement I think is going too far given the data. For example, another scenario that provides the requisite 1.41 ratio of usable capacity is that both the 30 kWh and 40 kWh nominal capacities have a usable capacity 5 kWh smaller than nominal.

Cheers, Wayne

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