="ttweed"
...I know that edatoakrun has claimed that the CW detailed energy usage figures can be used to calculate battery capacity degradation, but frankly, I have not been able to follow either his logic or methodology in doing so...
Maybe my comments on camasleafs recent two-LEAF range test will help to explain my reasoning?
http://www.mynissanleaf.com/viewtopic.php?f=44&t=5582&start=550" onclick="window.open(this.href);return false;
="ttweed"
...Can someone give me a compelling reason to have this update performed? What have you gotten out of it that you simply couldn't live without?
Well, another Carwings benefit I find useful, is that, by giving me a fairly accurate view of my LEAF's present nominal kWh capacity (however many Wh each "kWh" actually contains) I can fairly accurately calculate my present available "kWh" and remaining range at all times, by watching my dash and Nav screen m/kWh readouts (which both use the CarWings kWh reports) as I drive.
Notice in the quote below, that (for whatever reason) my reported kWh capacity from "100%" to VLBW has remained fairly stable for
~the last six months, varying only with battery temperature, as expected and perhaps with a small additional calender loss. Of course, I have no idea what the kwh reports will look like after it heats up again over the next few months.
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.
http://www.mynissanleaf.com/viewtopic.php?f=31&t=11987&start=40" onclick="window.open(this.href);return false;
So, since I know I presently have ~16 "kWh" available from my ~50 f battery, I also know, for example, that I have ~101 miles of range available to ~VLBW at 6.3m/kWh on my nav screen. In theory, I could have gotten almost as accurate (the 0.1 kwh rounding of both reports produces less accurate results when you use the, effectively lower resolution nav screen reports) estimate of my nominal kWh capacity.
But have any of you been able to do this, using the nav screen m/kWh, much less using the dash m/kWh with its 2.5% odometer error?
IMO, It would be a lot of unnecessary effort, just to get the less accurate results.
For example, on my 3/13 range test mentioned above, and shown in the "rate simulation" trip report below, I drove ~101.5 miles between "100%" and just past VLBW, with a 6.3 m/kwh report from my nav screen, and "16 kWh" reported from CW.
Last Wednesday, I ran this same test route, and with a slightly cooler battery (and unexpectedly) with considerably cooler air temperatures. My driveway, the first and last ~0.3 miles and ~150 ft of descent and ascent, are omitted by google maps, in the profile below:
I wound up getting ~98.6 miles on maybe a bit less than the ~16 kWh capacity reported on 3/13. I will post the CW kWh report, once I get it. BTW, the dash and nav screen reports at the end of the two tests were the same, 6.2 and 6.3 kWh respectively, for both the 3/13 and the 4/2 tests.
I was watching both my dash and nav screen on the 4/2 test, and at the farthest point, at the end of trip # 2, 47.2 miles from home, I had 5.1/5.3 m/kWh as opposed to the 5.3/5.4 m/kWh I had on 3/13. I realized that, due to the colder-than-expected driving temperatures, I would have to reduce my speed on the return trip, to make it over the ~4,4345 ft. pass at ~67.7 miles, if I wanted to avoid going too far past the LBW at that point, and avoid using the ~30 kW required on this grade, from a very low SOC battery.
Because I had a pretty good estimate of my remaining kWh, I was not compelled by
range anxiety to try to detour to try to recharge at the only possible location, a semi-reliable RV park in Burney, and was able to drive
only as slowly as I had to, which was 35 to 40 mph, and for only the ~7 miles climbing up and over Hatchet Mt pass, which I passed over about 1.3 miles and ~400 Wh past the LBW (which now occurs at roughly 13.7 kWh from "100%") as indicated by my 4.8 m/kWh nav/67.7 miles = ~14.1 kWh used.
I had never cut the range this close before, and put myself in this situation, and I don't plan to ever do so again.
It was a little embarrassing, to pull over a few times to let the (very light) traffic pass over those ~7 miles, but it was preferable to all alternatives.