CarWings vs. Odometer

[LEAFer]

Carwings "Driving Records" / "Annual" / "2011" / "Distance Traveled" = 13,759.3 (starting 1/20/2011) (AEE 4.9 m/kWh)
Carwings "Driving Records" / "Annual" / "2012" / "Distance Traveled" = 10,563.8 (through 9/29/2012) (AEE 5.1 m/kWh)

Carwings Total: 24,323.1 miles

Odometer (through 9/29/2012) = 26,235 miles

Calculated Carwings UNDER-reporting of miles travelled: 1,911.9 (call it 1,912) or 7.29%.

I know we've discussed some inaccuracies in Carwings before, but randomly browsing thru some of the monthly and daily data ... all appears "normal", in other words, I don't see any major discrepancies. And that's with the driver mostly ignoring the "OK" prompt. Thus theorizing that Carwings is missing 7%+ miles can not be explained by the ignored "OK" prompt.

Any opinions / theories ? How much is your % discrepancy ?

BTW: Looking at "Distance Traveled and Time" graph (which shows cumulative data) ... at 9/30/12 7pm PDT ... it already displays a bar for October even though the last data point available is 9/29, and this morning no such October bar was present. This brings up a secondary issue: does Carwings take into account local TimeZone when reporting miles and trips per (local) day ?

 

[ksnogas2112]

Yeah, mine is off by a couple hundred over 4 months of ownership. I suspect some is from the week the wife used it but I think it's the difference between gps tracking and wheel rotating on the road. The CW miles/Kwh is higher than the dash. Chalk another one up to "faulty" instrumentation. BTW mine is a 2012, ordered April delivered June.

 

[camasleaf]

What is CarWings? :lol:

I have not enter CarWings for probably a year, it does not seem it changed much.

 

[edatoakrun]

Yeah, mine is off by a couple hundred over 4 months of ownership. I suspect some is from the week the wife used it but I think it's the difference between gps tracking and wheel rotating on the road. The CW miles/Kwh is higher than the dash. Chalk another one up to "faulty" instrumentation. BTW mine is a 2012, ordered April delivered June.

Both the dash odometer and CW seem to use tire diameter to calculate miles.

AFAIK, everyone has reported the dash odometer is set correctly for new stock tires. It should begin to read a bit too high as the tires wear significantly.

Most have also reported that he CW miles driven is ~2.5% low with new tires, and so it should be close to correct, once your tires are bald...

The only other reasons besides this, I know of, why your numbers would vary, are that some of your CW miles were before the NTB11-041 update, or CW was not "Accepted:" either by the driver, or some malfunction.

I've lost a very few trips from my CW, but only when circumstances suggested I may have accidentally left the setting at not accepted, so I'm not sure if I ever had a malfunction or not.

More on CW at the old thread below:

On 9/7 I drove the same route...

According to CW, on this drive I used 18.7 kWh to drive 91.1 miles at average energy economy of 4.9 m/kWh.

I rechecked 2 other recent drives of 85-105 miles and each time CW has erred, under-reporting distance traveled, as compared with both my odometer and Google Maps, by 2.5%, +/- 0.1%.

Has anyone else-before or after the NTB11-041 update-seen this same odometer/CW mileage disparity?

If so, do you suppose this may reflect the similar discrepancy between the dash and screen numbers, as widely reported?
My car shows 4.3 m/kWh on the dash and 4.4 on the screen, as average since delivery.

Extrapolating from the chart, it appears CW may be saying the 1.7 kWh (8.5% from the chart, of 20.4 total kWh-anyone have a better number?) I had left at or near VLBW implies total available battery capacity of about 20.4 kWh.

So, from the limited info I can gather, looks to me that Carwings may now be accurate as to energy use.

Posts from others who can take the charge lower could verify this...

Comments from the SOC meter crowd, and also those who have metered L2 charging and can determine charge efficiency, as a % from Carwings reports, would also be greatly appreciated...

http://www.mynissanleaf.com/viewtopic.php?f=31&t=5423&start=10" onclick="window.open(this.href);return false;

 

[RegGuheert]

Most have also reported that he CW miles driven is ~2.5% low with new tires, and so it should be close to correct, once your tires are bald...

I just got NTB11-041a applied on Friday, so I am starting to look at Carwings again. My wife made a 40-mile trip yesterday and Carwings showed it to 2.3% shorter than the odometer reading. Rounding error on a 40-mile drive is about 0.25%, so this matches Ed's numbers.

I also have plenty of old trips which were not recorded since you must have particular settings for Carwings to report.

It seems there are many sources of error in Carwings!

 

[edatoakrun]

Most have also reported that he CW miles driven is ~2.5% low with new tires, and so it should be close to correct, once your tires are bald...

I just got NTB11-041a applied on Friday, so I am starting to look at Carwings again. My wife made a 40-mile trip yesterday and Carwings showed it to 2.3% shorter than the odometer reading. Rounding error on a 40-mile drive is about 0.25%, so this matches Ed's numbers...
quote]

FYI, I just checked my last four long trips, 60 to 108 miles, CW vs odometer.

Those four happened to have ~ .0237, .0245, and .0235, .0243 variations between the two.

The ~2.5% I saw last year was (IIRC) rounded to the nearest .1%, based on averaging a small sample of about 3-4 trips.

With both sources reporting only to .1 mile accuracy, I wouldn't be surprised if the actual number worked out to be closer to ~2.4 % if you were to take a look at very large sample, of the longest travel days, which I never have.

I guess you could also calculate over a CW "month" as long as you never forget to "accept".

I never went beyond google maps to verify my dash odometer accuracy either, BTW, but it was clearly always correct to a small fraction of one percent.

 

[DesertDenizen]

When I go to Carwings to check on the status of my charging, The Estimated Driving Distance with Climate ON and EDD with Climate OFF are always exactly the same.

 

[planet4ever]

I know we've discussed some inaccuracies in Carwings before, but randomly browsing thru some of the monthly and daily data ... all appears "normal", in other words, I don't see any major discrepancies. And that's with the driver mostly ignoring the "OK" prompt. Thus theorizing that Carwings is missing 7%+ miles can not be explained by the ignored "OK" prompt.

This statement surprises and puzzles me. I have never hit OK since getting the car. My wife occasionally drives it for a few miles, and I suspect she always does. The CarWings numbers I see certainly appear to count only when OK has been pressed:

Odometer mileage: 11125

CarWings distance 2011: 63.7
CarWings distance 2012: 37.5

Ray