Miles per kwh so far... my calcs vs. the LEAFs calcs

garygid said:

I believe that the Regen kWh is incorrectly handled when the "total kWh" is calculated.

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The problem isn't that simple ...

What is the problem, please?

This is the response I got from Nissan support on my question about the difference between miles/kWh in Carwings and the car:
 
Thank you for taking the time to personally contact us about your interest in the Nissan Electric Vehicle.
 
Discrepancy between carwings energy economy, and the miles/kWh indicated in the car
 
I apologize for the inconvenience. The shown average energy economy is different on the vehicle and website because the vehicle calculates with power-loss in motor. However, the website excludes power-loss in motor. This is actually a known issue that we are working to correct. Unfortunately, it will take some time for this to be accomplished.  If you have any additional questions, please do not hesitate to contact us.

Power loss? R they refering to loss from heat? Or con

I'm sorry but that makes no sense. I'm seeing a discrepancy of 50 percent or more (around 4.1 on the car and over 6.5 on Carwings). That would be a hell of a power loss!

Andy said:

This is the response I got from Nissan support on my question about the difference between miles/kWh in Carwings and the car:
 
Thank you for taking the time to personally contact us about your interest in the Nissan Electric Vehicle.
 
Discrepancy between carwings energy economy, and the miles/kWh indicated in the car
 
I apologize for the inconvenience. The shown average energy economy is different on the vehicle and website because the vehicle calculates with power-loss in motor. However, the website excludes power-loss in motor. This is actually a known issue that we are working to correct. Unfortunately, it will take some time for this to be accomplished.  If you have any additional questions, please do not hesitate to contact us.

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CARWING figures are WRONG.

Although Nissans explanation is questionable, at least they admitted that it is a known issue that they are working to correct. How hard can it be to just send the same number that the car displays to Carwings?

ok, Centralia trip yesterday. 65.5 miles on full charge. "10 miles" range left on return. MPK per car, 3.5 implies 18.71 KWH used. trying (for first time ever) to recharge to full from a deep discharge. i have determined that this will be only way to get good handle on charging efficiency.

i will say one time, i am starting to see what Cali Owners are seeing. despite it only being slightly warmer as spring approaches, my efficiency is going up. how do i know?

well, my CPK is dropping. went from 3.25 CPK to 3.2 CPK but my average electricity cost went UP from 10.2 CPK to 10.3 CPK at the same time. i am also averaging 5.2 -5.5 MPK on my commutes when hitting 5 was a rarity.

all of this is happening with an average temp increase of only 7-10º. can t wait till summer when most of the summer can easily be done without AC

DaveinOlyWA said:

...all of this is happening with an average temp increase of only 7-10º. can t wait till summer when most of the summer can easily be done without AC

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Dave, could you also be seeing other forces at work here? I remember when I first got my Prius I saw the mpg stats increase after a month or two of 'break in'. PriusChat posters postulated that bearings, tires, etc. might be responsible for it.

HIOJim said:

DaveinOlyWA said:

...all of this is happening with an average temp increase of only 7-10º. can t wait till summer when most of the summer can easily be done without AC

Click to expand...

Dave, could you also be seeing other forces at work here? I remember when I first got my Prius I saw the mpg stats increase after a month or two of 'break in'. PriusChat posters postulated that bearings, tires, etc. might be responsible for it.

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anything is possible, but i consider that to be about 98% unlikely. i attribute the difference to much less use of climate controls. when the OAT (outside air temperature) is in the mid 50's with even minimal sun creates enough radiant warmth that even cabin heat is not needed. that is not an options when temps are in the mid 40's. now is it acclimation?

oh ya, probably. when i was in Alaska, i can remember "spring" there in May when it would be in the 20's. we would be running around without shirts on because it was so warm. now after -30 for 6 months, 20 did feel plenty warm

garygid said:

What is the problem, please?

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Don't know. We can't get the figures shown by Leaf from the breakup figures carwings shows.

But, there is strong correlation between Leaf's figures & carwings'.

I've started a new thread on this problem.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=3123&start=0

try this and do not make any conclusions unless you can average at least 10 days or so.

from Carwings; take (Electricity consumed by the traction motor) - regen plus (Electricity consumed by the vehicle accessories)

this should give you power used from the wall more or less.
we take my stats from 3/22 we have

MPK= 7.7

on formula above we have

9.6 - 3.8 +0.4 = 6.2 kwh from the wall. with MPK readings carwings suggests we drove 6.2 * 7.7 = 47.7 miles (actual 49.5)

makes sense?? sure it does... pretty close to car

BUT

now on that date, readings from car distance traveled 49.5 @ 5.5 MPK which implies energy used to be 49.5/5.5 = 9 kwh consumed....hmmm. that formula does not work with carwings though especially when taking out regen power and its this regen figure that appears to be vague as to how it fits in the calculations

so if we go back to the top. and make the assumption that regen should not be removed from what the traction motor used as its somehow absorbed we then come up with a KWH used that matches the car (or nearly so) of around 9 kwh.

but that also assumes that the climate control power should be removed from the traction motor which does not really make sense to me (but most of this doesnt anyway so we will go with it)

so that would mean that 9.6-.04 = 9.2 from traction motor used from the wall and that the regen was playing a part in providing the extra power which means that the sets of numbers we see are using two different sets of formulas....


so, keep in mind; you wanted to know why it was not a straight forward answer, so now you know



bet you wont make that mistake twice!!

I didn't know where else to post this so this thread seemed as good as any...

I've had the car two months now and I've gotten two electric bills.

I've driven about 1900 miles in those two months.

On average, I used about 250kWh more off peak energy a month than I
used last year. Currently that's about double my normal off peak
usage. Once the summer comes, it will be less than double. I haven't
really turned on the A/C yet.

This extra usage raised my electric bill about $17.

That's an average energy cost of 6.8 cents per kWh and an average operation cost of 0.89 cents a mile...which comes out to about 3.8mi/kwh.
Carwings seems to be down right now, but I believe my cawings average is about 4 mi/kwh so it sounds about right.