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dgpcolorado
Posts: 3178
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Delivery Date: 15 Dec 2011
Location: The Western Slope, Colorado

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Thu Sep 13, 2012 11:50 am

My winter numbers include pre-heating, so charging efficiency can't be calculated.
edatoakrun wrote:
dgpcolorado wrote:August mileage:

Wall-to-wheels: 4.46 miles/kWh

Dash: 5.0 miles/kWh

Charging efficiency at 240 V, 16 A: ~89% ...
It appears your reported charging efficiency has increased from ~80% to ~89% since you begin your (excellent) observations on this thread. Have I stated this correctly?

I think you might want to consider the possibility that your LEAF is not reporting consistent kWh use figures, and so is miscalculating the dash m/kWh.

Consider what I have seen, using (admittedly less precise) time of charge to 80% observations:
...I did not meter my charge a year ago, but I did record the charge time, and also got an accurate 16 amp 240v recharge time on 9/8/12. It took 4 hours and 16 minutes to reach 80% (and another one hour and 11 minutes to reach “100%”) following this trip.

Assuming a 3.75 kWh/h draw from my 16 a modified Panasonic charger, and the 16.7 total capacity from VLBW to 100% charge, I believe that this would indicate a charging efficiency from ~VLBW to the “80%” level of ~96%, which is implausible, in light of all reports of charging efficiency by others.

This compares to a recharge time of ~4 hours 25 minutes to reach “80%” following my first range test, on 9/7/11, with a reported 18.7 kWh used from 100% to about the same capacity level, ~VLBW.

This would seem to indicate a charging efficiency of from ~VLBW to 80%” a year ago of ~89%. but remember, this was recorded after my LEAF had seen most a of a Summer of use, so my LEAF’s m/kWh use reports might have already started to “drift,”meaning this percentage may already have been somewhat inflated, and the kWh use similarly understated...
http://www.mynissanleaf.com/viewtopic.p ... 4&start=30" onclick="window.open(this.href);return false;

I now wonder if I would have seen about the ~80% efficiency that you did, if I had monitored it from new, before my first Summer of ownership.
Blue 2012 SV Dec 2011 to Feb 2016
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edatoakrun
Posts: 5222
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Leaf Number: 2184
Location: Shasta County, North California

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Thu Sep 13, 2012 12:12 pm

DaveinOlyWA wrote:
TomT wrote:I always get it on my way to work. Of course, that is with a gradual 1,400 foot elevation drop... Going home, not so much!
DaveinOlyWA wrote:news flash; it is VERY possible to get over 6 miles/k without cheating. i have done it several times along with several other members of the board.

i just did it a week ago and yes it was downhill to downtown Oly AND back. 6.2 miles/K over 22 miles. i have actually done the same trip several times at better than 6 and can only hit 6 if the temps are over 80º. otherwise its my "normal" 5.5-5.8
Hell, I'm getting 6.4 m/kWh from Dash and CW driving over mountain passes now!

Which is one of the reasons why I have come to doubt that these reports are reliable...
Another range test, with recharge times compared, to give another view of the possible error in my LEAF's kWh use reports.

On 9/8/12 I made another "100%" to VLBW range test, repeating the same route I drove on 8/18/12, with close to 6,000 ft each of ascent and descent, with very slight variations in the final miles prior to VLBW, and got these results:

107.4 miles to VLBW, and 109.4 miles in total by odometer...

As reported by CW, 106.8 total miles (~2.5% under report), at 6.4 m/kWh, using 16.7 kWh...
http://www.mynissanleaf.com/viewtopic.p ... 4&start=30" onclick="window.open(this.href);return false;
no condition is permanent

EatsShootsandLeafs
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Thu Sep 13, 2012 6:45 pm

dgpcolorado wrote:
EatsShootsandLeafs wrote:I only have a couple hundred miles on this, but it seems to me that EPA substantially underrates its mileage. EPA says 2.94 I think miles/kWh.

On my third gen Prius it was rated at 51/48 and I have to say I found it quite a challenge to get those numbers. It would require me driving very gently and was easy to get worse. In my Leaf so far, also driving very gently, I'm getting a consistent 4.2-4.3 kWh. That's 45% better mileage than EPA. I know it will be worse in the winter, but the Prius was worse in the winter, too (not to mention it, as with all ICE cars, suffers a serious hit in mileage during engine warm up for those first five min).
How are you measuring your 4.2-4.3 miles/kWh? The EPA number of 34 kWh/100 miles (2.94 miles/kWh) almost certainly is calculated "from the wall".

That's not to say that you aren't beating the EPA number, you are, but if you are using the mileage efficiency reading on the dash you are overestimating you mileage somewhat. How much depends on whether you do L1 or L2 charging and any pre-heating or pre-cooling.

Last I checked, at eight months, my cumulative mileage from the wall was 3.8 miles/kWh. That includes all of winter and part of summer. My monthly numbers from the wall:
January 3.23 miles/kWh
February 3.29
March 3.57
April 3.97
May 4.36
June 4.48
July 4.41
August 4.46

The weather (and pre-heating) effect is quite apparent. If I drove freeways—there aren't any within LEAF range here—I would expect my mileage numbers to be somewhat lower and closer to the EPA estimate. If I lived at sea level they would be sharply lower. If I lived in the flatlands they would be higher.
I'm using the dash number. I am using L1 charging, so assuming 75% charge efficiency.

Here's my math: If car is getting 4.3 miles/kWh I actually need to pull 1.33 kWh from the wall. My kWh are $.105, so this puts my price per kWh in the car at $.14. Gas around me is $3.92, so for that I'm buying 28 kwh in the car = 120 MPGe. So that's 20% over EPA. This makes more sense now...4.3 * .75 = 3.23 miles/kWh after accounting for efficiency loss, so again just around 20% better than EPA not 45%.

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DaveEV
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Fri Sep 14, 2012 12:33 am

EatsShootsandLeafs wrote:Gas around me is $3.92, so for that I'm buying 28 kwh in the car = 120 MPGe. So that's 20% over EPA.
EPA MPGe has nothing to do with the cost of gas - only the energy equivalent of gas where the EPA assumes 1 gallon of gas = 33.7 kWh.

So if your dash reads 4.3 mi/kWh and you charge over L1 at 75% efficiency - you are getting 3.23 mi/kWh from the wall. 3.23 mi/kWh * 33.7 kWh = 109 MPGe, not 120 MPGe.

EatsShootsandLeafs
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Fri Sep 14, 2012 3:51 am

drees wrote:
EatsShootsandLeafs wrote:Gas around me is $3.92, so for that I'm buying 28 kwh in the car = 120 MPGe. So that's 20% over EPA.
EPA MPGe has nothing to do with the cost of gas - only the energy equivalent of gas where the EPA assumes 1 gallon of gas = 33.7 kWh.

So if your dash reads 4.3 mi/kWh and you charge over L1 at 75% efficiency - you are getting 3.23 mi/kWh from the wall. 3.23 mi/kWh * 33.7 kWh = 109 MPGe, not 120 MPGe.
Thanks :) I thought it was a number to get lay people (apparently I'm one of them) a quick way to compare cost, though I always knew it would have to continually change as gas did.

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dgpcolorado
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Location: The Western Slope, Colorado

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Fri Sep 14, 2012 7:49 am

EatsShootsandLeafs wrote:...This makes more sense now...4.3 * .75 = 3.23 miles/kWh after accounting for efficiency loss, so again just around 20% better than EPA not 45%.
Yes, you've got it! (And you can see why I have my meter to measure the electricity use accurately, even when doing things like pre-heating while plugged-in.)
Blue 2012 SV Dec 2011 to Feb 2016
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dgpcolorado
Posts: 3178
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Thu Oct 04, 2012 3:53 pm

September mileage:

Wall-to-wheels: 4.30 miles/kWh

Dash: 4.9 miles/kWh

Charging efficiency at 240 V, 16 A: ~88%

My mileage is starting to decline again with the start of cooler weather and some serious mountain climbing with the LEAF.

Notes: No preheating used, so charging efficiency can be calculated, although the dash mileage numbers are too coarse for precision. Driving temperatures were mostly 60s and 70s with some 40s and 50s. Battery temps of five bars most of the time with six bars on warmer days after several hours. Elevation range: 11,000 feet to 5750 feet. All driving includes steep hills. No multi-lane highway driving at all. Some of the driving is on dirt roads.

My monthly numbers from the wall:
January 3.23 miles/kWh
February 3.29
March 3.57
April 3.97
May 4.36
June 4.48
July 4.41
August 4.46
September 4.30

The weather (and pre-heating) effect is quite apparent. If I drove freeways—there aren't any within LEAF range here—I would expect my mileage numbers to be somewhat lower and closer to the EPA estimate. If I lived at sea level they would be sharply lower. If I lived in the flatlands they would be higher.
Blue 2012 SV Dec 2011 to Feb 2016
CPO 2014 Tesla S60 Mar 2016
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dgpcolorado
Posts: 3178
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Delivery Date: 15 Dec 2011
Location: The Western Slope, Colorado

Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Fri Nov 02, 2012 3:24 pm

October mileage:

Wall-to-wheels: 4.06 miles/kWh

Dash: 4.8 miles/kWh

My mileage continues to decline with the cooler weather.

Notes: Some preheating used, so charging efficiency can't be calculated. Driving temperatures were mostly 50s and 60s with some 20s, 30s, 40s and 70s (it's that time of the year again: wide temperature variation). Battery temps of five bars most of the time with six bars on warmer days after several hours and one brief morning with four bars. Elevation range: 8,000 feet to 5750 feet. All driving includes steep hills. No multi-lane highway driving at all. Some of the driving is on dirt roads.

My monthly numbers from the wall:
January 3.23 miles/kWh
February 3.29
March 3.57
April 3.97
May 4.36
June 4.48
July 4.41
August 4.46
September 4.30
October 4.06

The weather (and pre-heating) effect is quite apparent. If I drove freeways—there aren't any within LEAF range here—I would expect my mileage numbers to be somewhat lower and closer to the EPA estimate. If I lived at sea level they would be sharply lower. If I lived in the flatlands they would be higher.
Blue 2012 SV Dec 2011 to Feb 2016
CPO 2014 Tesla S60 Mar 2016
One car, no ICE, at last!

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evnow
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Sat Dec 01, 2012 6:30 pm

Here are my stats so far.

Image

Here is the comparison to the average seattle temperature (now taken from NOAA).

Image
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
Model 3 : 5/10/2018 to ?

LEAFfan
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Re: I Beat EPA's 2.9 Miles/KWh : Report Your Monthly Mileage

Sat Dec 01, 2012 6:52 pm

evnow wrote:Here are my stats so far.

Image

Here is the comparison to the average seattle temperature (now taken from NOAA).

Image
It looks like your miles (all the months) are based on '21' which would be a full capacity battery. You haven't lost ANY capacity? Your meter still shows 281 and 100%?
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2013 LEAF World Record for Most Miles Driven On One Charge-188 miles/8.8 m/kW h
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