...If the roads are dry and "uncontanimated" with snow, and the heater is off, the LEAF will get about 4 miles/kWh at 65mph regardless of the temperature on a level, no wind roadway...
DaveinOlyWA Tony...this entire conversation started with the bolded text you put out and i will say it now and forever is total Bullshit...
Nightrider ...I have been getting 5.2 m/kwh at 60 mph on I-95 a lot lately, on flat roads without climate control....
Nightrider, do you have a recent report on your total battery capacity from “100"%” to VLBW?
The CarWings kWh report number is preferable, but you can use the less accurate nav screen or dash m/kWh calculation to get this number, if you must.
I expect the reason so many posters on this and other threads are seeing widely varying dash m/kWh reports is probably because those reports are inaccurate, and you are only continuing to waste your time when you rely on this data source.
The dash m/kWh evidently reflect a constant error of ~2.5%, on every LEAF. You can easily avoid that error just by using the nav screen m/kWh report (if you have a nav screen).
But if the kWh use report your LEAF is using to calculate both those numbers is also incorrect, you have a real garbage in/garbage out data problem.
I believe my LEAF has a very significant error in its kWh use reports, as determined by range tests, and also to some extent, by recharge capacity tests.
From the wildly varying MNL posts on dash m/kWh, I would be surprised if many other LEAFs did not have a kWh report error,
just as mine does, though probably of varying severity.
To see this kWh reporting error, you need a history of controlled range tests, or of accurate recharge capacity tests, to show that any decrease in your battery capacity is due to this error, and not due to an actual decrease in available battery capacity.
I first noticed, and posted about this error last Summer, when my CW m/kWh (whose 2.5 % odometer error error is replicated by the dash/kWh) first showed a large and unexplained increase of m/kWh, from 4.9 to 5.7, based on the kWh use report reduction from 18.7 to 16.8.
...I think that my range tests may indicate that whatever method my LEAF uses to calculate kWh, is variable, and has been significantly understating the recent amounts of kWh use, and has probably increasingly inflated all my m/kWh reports, from the dash, nav screen, and CW.
And of course, this could reflect with Tick Tocks observations of variable “gid” Wh values. Gids with higher Wh content could lower the calculated kWh numbers, and raise all the m/kWh results.
Maybe this is what I am seeing, from yesterdays range test. I tried to replicate as accurately as possible, my earliest range test,of almost a year, and almost 10,000 miles ago, to test this hypothesis.
I chose a day with very close to the original temperature condition, and drove the exact same route over the first 87 miles of the trip, using the same mode (eco) and used my original trip logs to closely replicate the same elapsed times for each of the three (same distance) legs of the trip.
The results from 8/30/12 were:
97.3 miles to VLB, 98.9 miles in total, by the odometer.
CW: 96.5 (~2.5% under-report) total miles, at 5.7 m/kWh, 16.8 kWh used from 100% to about the same capacity level, slightly past VLBW.
Compare this test with my first test on 9/7/11:
91.5 miles to VLB, 93.4 in total, by the odometer
CW: 91.1 (~2.5% under-report) total miles, at 4.9 m/kWh, 18.7 kWh used from 100% to about the same capacity level, slightly past VLBW.
I do not believe that the slight increase in range over the last year reflects any increase in battery capacity. On the contrary, I expect that my total capacity ( though maybe not the amount of kWh that the BMS is allowing me to access) has declined by an undetermined amount, but it cannot be detected due to the “noise” of uncontrolled variables in a range test....
Below is a summary of the CW reported battery capacity since Summer of 2011.
I only began regularly testing all the way to VLBW on this route, after the large and unexplained "phantom" loss of capacity show edup, in the Spring of 2011.
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.
Back to the immediate question of how range and battery capacity vary with both battery temperature while charging and driving temperature, After the hundreds of comparisons of range and capacity variations with temperature I have made since, the results I got 18 months ago still seem close to correct, though I now believe all test results are less certain and accurate since the kWh reports you need to use for this test, are just as suspect as when you use them for a range test.
On 11/8 (11) I attempted to replicate the route and conditions of an earlier trip, which I had kept careful notes of, to try to see what sort of range reduction is caused by reduced m/kWh due to lower temperatures, and what proportion of this reduction is due to reduced battery capacity. I did this on a dry day with windows up, without using the heater or windshield wipers. I believe that I got about 5% reduction in battery capacity, and a slightly larger decrease in driving efficiency (m/kWh) resulting in a total range reduction of over 10%. This is the same trip I made several times over the summer, and posted details of on this thread:
..My trip ... was 87.6 miles by odometer (85.5 miles by CarWings-see other thread for info on this 2.5% discrepancy) with between 5,000 and 5,500 ft. of total ascent and descent, carwings reports 16.8 kWh consumed and 5.1 m/kWh. I believe my total battery capacity after charging to 100%, was about 20.4 kWh.
When I made the (almost) identical drive on 11/8 of 88 miles (85.9 as reported by CW) CW reported 17.6 kWh consumed and 4.9 m/kWh. I believe my total battery capacity when I left home with a 100% charge was probably close to 19.4 kWh...
...this approximately 40 degree decrease in temp when charging, and 50 degree reduction when driving, resulted in about 10% recorded range reduction...
IOW, many subsequent tests seem to indicate that my LEAF’s kWh use report error varied very little between these two trips, which were driven only ~ 2 months apart.
If you want to test for these temperature variables yourself, you will need to use the Carwings reports for the same reason you need them for any other accurate range test, to get the regen kWh report to check for driver efficiency, and the kWh use data before it’s accuracy is reduced by the m/kwh dash and nav screen displays.