Sorry, but I think introducing a 2.5%+ error into your kWh use calculations by using the dash m/kWh is significant.dgpcolorado wrote:With the exception of some older cars that may need a firmware update, the console (Carwings) mileage efficiency meter reads about 0.1 mile/kWh higher than the dash one. The difference isn't significant for diagnosing range problems.cwerdna wrote:On this note, IIRC, it's been established that the dash (black and white LCD in the instrument cluster) m/kWh reading is the one to look at, right? I remember hearing that CarWings was a liar and used to be way off. Not sure about now...vrwl wrote: What is your m/kWh reading on the dash? Is it reset for every trip?
Since you three, and other LEAFers still don't seem to have determined the mathematical relationship between the various kWh use sources, please check with CarWings to see if your LEAF shows the same results that every other LEAF, AFAIK, has reported, to date:
http://www.mynissanleaf.com/viewtopic.php?f=27&t=11769" onclick="window.open(this.href);return false;...Here are my suggestions, for you and other CW users.
All 2011-2 LEAFs, AFAIK, have reported the same CarWings odometer and Dash m/kWh error of consistently under-reporting by ~2.5%.
So if your CW miles driven is ~2.5% lower than your dash odometer miles, and your dash m/kWh is showing ~2.5% less than your nav screen m/kWh (0.1 m/kWh lower below ~6 m/kWh, and 0.2 m/kWh lower when you are getting over ~6 m/kWh) this is "normal" for 2011-2012 LEAFs.
Hopefully, Nissan has fixed this error in the 2013s. Any readers have a CW equipped 2013? Please check and report back.
If you are "missing" more miles than this, go to the "rate simulation" page at the CW site.
Here, each "trip" (each start/stop cycle) will be individually reported. Make sure that each of the "trips" you have made each day, is showing up. Each trip will show the same ~2.5% under-report of miles driven as your daily total, and each m/kWh report there will match your dash (if you reset it) for the corresponding trip, again showing the same ~2.5% under-report error.
The Dash, nav screen and CW m/kWh all are mathematically "correct" as a function of the total kWh use reported by CW for every trip, day, or months driving.
It's just that the dash uses the same ~2.5% understated miles to make its calculation of m/kWh as CW does, while the nav screen is always accurate as a function of reported kWh use, as it uses the dash odometer miles, for the m/kWh calculation.
BTW, while every LEAF driver, AFAIK, has reported the dash odometer as very close to correct, while using stock tires and wheels, IMO it wouldn't hurt to confirm your dash odometer is correct, by checking with another source, such as Google maps...
Below is how Carwings has reported the total energy use from "100%" to ~VLBW on my warm climate LEAF two years from the factory and with ~16,000 miles on the odometer.
While the reported kWh use has dropped quite a bit, My LEAF has displayed no significant loss of range from my first test, to most recent, on range tests of 95-113 miles, when corrected for all test variables, including speed, temperature both when charging and when driving, and my own driving efficiency (as reflected in the regen kWh reported by CarWings).
Of course my battery has lost capacity in the last 18 months, it just not yet a large enough loss to show up clearly in a range test, and is, IMO, nearly certainly far less than the kWh use results below, showing capacity loss approaching 15% just over the last 18 months (when adjusted for battery temperature) would indicate:
All charges prior to testing were to “80%", battery allowed to return to ambient temperature, and then charged @ 16 A 240 V to “100%”, two to three hours before range/capacity test begins, and then left plugged into the EVSE until departure.
IMO The distance driven at the point where the battery temp bars increased, when that has occurred, is useful data as to the relative battery temp and temperature the (temperature variable) battery capacity when the "100%" charge was completed.
9/7/11 18.7 kWh from "100%" to VLBW, 6 dash battery temp bars constant (as recalled later)
5/10 12 17.2 kWh, 5 to 6 temp bars ~mile 73
5/31/12 17.5 kWh, 5 to 6 temp bars ~mile 5
6/17/12 17.5 kWh, 6 temp bars constant
8/18/12 17.0 kWh, 6 temp bars constant
8/30/12 16.8 kWh, 6 temp bars constant
9/08/12 16.7 kWh, 5 to 6 temp bars ~ 4.6 miles
10/1/12 16.6 kWh, 6 temp bars constant
11/3/12 16.2 kwh, 4 to 5 temp bars ~mile 14
1/31 15.7 kWh, 4 to 5 temp bars ~mile 24
2/16/13 15.8 kWh, 4 to 5 temp bars ~mile 18
3/1/13 15.6 kWh, 4 to 5 temp bars ~mile 18
3/13/13 16.0 kWh, 5 bars temp constant
I think it is nearly certain, that the LEAF "gauge error" that has shown up in premature battery capacity bar loss and Wh/gid error in other LEAFs is also displaying itself in the dash and nav screen m/kWh, and also in the (more accurate) CarWings kWh use reports, from my LEAF, as I have posted above.
IMO, any LEAFer who can learn to use CarWings, may see the same sort of results I have, and also be able to largely differentiate any range loss due to real battery capacity loss, from their LEAF's questionable kWh use reports, as I believe I have been able to do.