RegGuheert said:
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For reference, NREL got the following efficiency numbers using L2: 25.414kWh from wall and 21.381 from the battery, for an efficiency of 84%. If I "L2-ise" your results by subtracting 10.2 hours * 300 watts =3.06 kWh from your charge, I get (97.4mi/6.2)/18.95 kWh = 82.9% (CW) or (97.4mi/6.0)/18.95 kWh = 85.6%. Those look to be pretty much in the ballpark to me, particularly the Carwings one.
Rather than try to “L2-ise”, my L1 results, lets take a look at my 2/17 recharge session using Phil's L1 efficiency results to the battery, and other sources for the efficiency of the battery charge and discharge itself, to try to estimate “meter to Inverter" efficiency.
Please review my tentative conclusions below, and please comment if you find any (of what I expect are many) possible errors.
Following 97.4 mile range test ton 2/16/13, starting Odometer ~15,450 miles, where I got CW/nav screen report of of 15.8 kWh use from “100” to the VLBW, dash indicated “15 hours” recharge time to “80%”. test began with 4 temp bars, and went to 5 ~18 miles into the test, where it stayed to the end.
Recharged overnight (~35 f low temp) on L1 and monitored with kill-a-watt, ...17.52 kWh and 12 h 25 m to (nine bars) “80%”.
First, my results were 17.52 kWh/12.42h= 1.41 kw charge rate for the VLBW to “80%” charge, very close to the 1.436 Phil reported, and the difference might be explained by the fact that his results were from a charge session done at ~20 f higher temps.
http://www.mynissanleaf.com/viewtopic.php?f=31&t=8583" onclick="window.open(this.href);return false;
I finished my charge from “80%“ to 100’% in 3 h 10 m (total charge time 15 h 35 min) and 22.01 kWh in total, showing 4 temp bars and at ~ 45 f ambient .
15.58h x 311w (Phil's L1 loss figure, =4.845 kWh loss while charging , so 22.01-4.85 = 17.15 kWh to the battery..
The AVTA LEAF Efficiency analysis:
http://www.transportation.anl.gov/D3/data/2012_nissan_leaf/AVTALeaftestinganalysis_Major%20summary101212.pdf" onclick="window.open(this.href);return false;
Reports c to e L2 efficiency =17.957/18.529= .969.
Another source, NREL:
http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2012/veh_sys_sim/vss030_lohsebusch_2012_o.pdf" onclick="window.open(this.href);return false;
reports .97 for this c/e value
969 x 17.15kWh =16.62 kWh. 16.62 kW/22.01= ~75.5% efficiency. I believe there are a few factors I skipped in this analysis, but I think they mostly bias toward a higher result, and are small enough that hey could cause the efficiency to increase only slightly from that 75.5%, so I’ll leave them aside, for now.
In comparison, I got 15.8/22.01= ~72% efficiency, using the 15.8 CW kWh use, about~0.8 kWh (~5% ) less than the 16.62 in the analysis above.
So it looks to me like each nominal kW I used, as reported on this range test by CW, may actually have held ~1,050 WH.
And I actually probably used ~16.6 kWh to drive the 94.7 miles between “100%” and ~VLBW, rather than the CW reported 15.8, IF we assume the recharge was equal in kWh to the charge I used.
For reasons l will eventually get to on my range test thread, a percentage error of this magnitude looks very plausible to me.