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NREL LEAF Teardown and Detailed Testing

Posted: Thu Oct 11, 2012 1:08 am
by DaveEV
cwerdna found the NREL detailed testing and teardown data for the LEAF. The goods are buried in these 2 PDFs:

http://www1.eere.energy.gov/vehiclesand ... 2012_p.pdf" onclick="window.open(this.href);return false;
http://www1.eere.energy.gov/vehiclesand ... 2012_o.pdf" onclick="window.open(this.href);return false;

From the 2nd one comes this great slide showing system efficiency:

ImageUploaded with ImageShack.us

Energy from the wall from dead to 100%: 25.414 kWh
Energy from the onboard charger to battery: 22.031 kWh
Energy from the battery during discharge: 21.381 kWh

Good stuff!

Re: NREL LEAF Teardown and Detailed Testing

Posted: Thu Oct 11, 2012 6:22 am
by Stoaty
drees wrote:Energy from the wall from dead to 100%: 25.414 kWh
Energy from the onboard charger to battery: 22.031 kWh
Energy from the battery during discharge: 21.381 kWh
I'm shocked! :o Are you suggesting that the range test in Arizona, which used the figure of 21 kwh available energy from the battery (leading to a range of 84 miles for a new Leaf) was CORRECT??? Absolutely shocked! Who could have guessed that the guys who obsessed and argued about, tested extensively, etc. would be more accurate than the armchair quarterbacks penning articles for the internet??? Looks like vindication to me.

PS This info is going into the Wiki ASAP.

Re: NREL LEAF Teardown and Detailed Testing

Posted: Thu Oct 11, 2012 6:43 am
by RegGuheert
Stoaty wrote:Are you suggesting that the range test in Arizona, which used the figure of 21 kwh available energy from the battery (leading to a range of 84 miles for a new Leaf) was CORRECT???
No, they were NOT correct. They were actually conservative! In other words, the degradation from new was actually higher than what was published!

Re: NREL LEAF Teardown and Detailed Testing

Posted: Thu Oct 11, 2012 6:57 am
by Stoaty
RegGuheert wrote:
Stoaty wrote:Are you suggesting that the range test in Arizona, which used the figure of 21 kwh available energy from the battery (leading to a range of 84 miles for a new Leaf) was CORRECT???
No, they were NOT correct. They were actually conservative! In other words, the degradation from new was actually higher than what was published!
Thanks for the correction. ;) Yes, the range at 4 miles per kwh would be 85.5 miles. 84 miles is too conservative, but let's give them a pass since the difference is only 1.8%. :D

Added to Wiki as more definitive documentation of the range of a new Leaf:

http://www.mynissanleaf.com/wiki/index. ... acity_Loss" onclick="window.open(this.href);return false;

PS On the previous page of that second PDF there is interesting information on the energy used for heating/cooling using standard test protocols:

Heater - 2.5-5.2 kw
A/C - 1-1.5 kw

There are also figures on energy consumption per mile, assuming a much slower speed for winter driving.

Re: NREL LEAF Teardown and Detailed Testing

Posted: Thu Oct 11, 2012 7:16 am
by mwalsh
It's a nice document. But I don't think there's much in it that we hadn't already figured out for ourselves (or were pretty close in guessing). Still, nice to have the validation, I suppose.

That these figures needed to be confirmed by a third party and not by Nissan should probably the biggest take-away! :?

Re: NREL LEAF Teardown and Detailed Testing

Posted: Thu Oct 11, 2012 11:51 am
by DaveEV
Stoaty wrote:Yes, the range at 4 miles per kwh would be 85.5 miles.
That does assume that the mi/kWh gauge is accurate. And since the gauge only reads to the 0.1 mi/kWh, technically a reading of 4.0 mi/kWh and 21.381 kWh usable could mean anything from 3.95 mi/kWh / 84.5 mi to 4.04 mi/kWh / 86.4 mi a 2.2% difference in itself. So any test results relying on the dash reading to be accurate should not count anything less than 2.2% as being significant or noteworthy.

The NREL advanced vehicle testing typically gives a full report of motor/vehicle efficiency at some point in time (look at the Sonata hybrid data in the first PDF). I couldn't find any such report yet, so hopefully they publish additional information at some point in time.

Re: NREL LEAF Teardown and Detailed Testing

Posted: Thu Oct 11, 2012 12:40 pm
by Boomer23
FWIW my range test when my LEAF was new yielded 85.6 miles at 4.0 mi/kwh indicated.

Re: NREL LEAF Teardown and Detailed Testing

Posted: Thu Oct 11, 2012 9:39 pm
by TonyWilliams
Boomer23 wrote:FWIW my range test when my LEAF was new yielded 85.6 miles at 4.0 mi/kwh indicated.
Great find with this test.

Guys, we expected the "new" cars to pass 84 miles in Phoenix. We used that number to align with Nissan's data, and our over one year old 21kWh baseline (and Nissan's, too, effective Dec 2011).

I fully expected any car with 2600 feet air density, and 80F batteries would be 86-89 miles, which I would just call 104% (for 87.5 miles). But, of course, the car that went 59 mile is only 67% of 87.5 miles, and with 8 of 12 capacity bar segments is 60-66%.

I think we did well.

Re: NREL LEAF Teardown and Detailed Testing

Posted: Fri Oct 12, 2012 2:43 am
by RegGuheert
TonyWilliams wrote:I think we did well.
I think you all did an outstanding job!

It is also nice to have some "official" measurements of usable pack energy.

Re: NREL LEAF Teardown and Detailed Testing

Posted: Fri Oct 12, 2012 7:03 am
by garygid
Too bad the testers did not report GID readings.

22000 / 281 = 78.2

Or 22000 / 80 = 275