TLeaf
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Leaf Number: 000225
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LEAF Dyno Run

Mon Aug 22, 2011 11:00 pm

So I finally caved and scheduled an appointment with a dyno for last Friday.. Though I have to admit to being a bit nervous about the whole process (I've watched a few too many dyno failure videos), the whole thing turned out to be pretty fun. Showing up at the shop "early" in the morning (they had only just opened up at 10:30am), it took a bit of time for them to clear away the dyno area, but once that was done, the car was hooked up and ready to go sooner than I would have expected (once again, cue fear of car flying off of dyno).

The first few minutes on the dyno were spent slowly ramping the motor up in speed in order to make sure everything was tied down securely. This was also a good time for the tech to learn how to operate the car and share a few laughs with his co-workers ("Hey, you better turn off those headlights to get another 5hp!"). After that, it was time for the real deal! Though this is where some car owners would turn away, I watched in fascination as the tires on the car first squealed in protest and then quickly ramped up to a reported 97mph. The procedure happened a second time and, before I knew it, the whole endeavor was over. 30 minutes, start to finish.

Shown here is the graph for the two official dyno runs. In both cases the car was in 'drive', but one involved mashing the accelerator while the other involved a neutral drop. Though the lines do look a bit different between the two, I'd be highly dubious about both lines below 30mph as the wheels on the LEAF were definitely outpacing the dyno on both runs at this point. As much as I'd like to say that the LEAF simply had too much torque for the the dyno to keep up, I'm sure it was some combination of both high torque and the low rolling resistance tires. In any case, note that this is a horsepower vs. speed graph as we had no way to measure motor RPMs. Since we're talking about a single-speed car, however, the two graphs should look identical.

On the matter of torque, owing to the same lack of RPM monitoring, I'm afraid we couldn't get any official torque numbers.. Though some would therefore consider this a wasted outing, the changed attitude of the tech after the dyno runs was priceless. Whereas before he was indifferent to the whole matter of testing an electric car, after the fact I believe he was an EV convert. Besides, since we're talking about a single-speed car, I wonder if we could do some back-calculating to go from vehicle speed to RPMs. According to this link, the relation between horsepower and torque is straightforward enough in which case we should end up with something very similar to the typical declining torque "curve" of a DC motor. This has me a bit confused as I could have sworn the LEAF has an AC synchronous motor which operates a bit differently. Any takers??

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TonyWilliams
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Re: LEAF Dyno Run

Mon Aug 22, 2011 11:15 pm

Awesome stuff there.

Figuring the motor RPM should be very straight forward, and at 95-ish mph, you should have had 10,300 RPM, therefore 47.5 mph would be 5,150 RPM. Right there is your torque / hp equal mark, so 105 hp was about 105 ft/lbs of torque.

I get about 212 ft/lbs of torque at [edit: about 3200 RPM], assuming 105hp there. The motor is definitely AC, as there is an inverter for the battery (your valve cover under the hood).

You could reasonably guessimate the RPM at various points to determine torque using the classic formula, HP = (Torque x RPM) / 5252

http://en.wikipedia.org/wiki/Horsepower
Last edited by TonyWilliams on Tue Aug 23, 2011 8:58 am, edited 1 time in total.

JohnOver
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Leaf Number: 4232
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Re: LEAF Dyno Run

Mon Aug 22, 2011 11:58 pm

Excellent! Thank you for doing this...
2011 LEAF (Silver SL+QC) - 6/24/11 (on 2/3/08 reserved an Aptera 2e #372)
AV EVSE, plus Ingineer's 240V upgrade, and a fist full of adapters
Other cars: '05 Honda Accord Hybrid, '96 Honda Odyssey
6.5 kW PV, making ~24 kWh per day (average).

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DaveEV
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Re: LEAF Dyno Run

Tue Aug 23, 2011 12:00 am

That is an impressively flat horsepower curve right there!

Most ICE vehicles would die to get a curve that flat, though the 105 hp peak isn't much to write home about. :)

Thanks for doing this - given the wheelspin you were seeing I'd have to assume that the actual peak may be a bit higher at lower speeds...

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planet4ever
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Re: LEAF Dyno Run

Tue Aug 23, 2011 12:44 am

So, what is the explanation for 97.34 mph when power drops to zero at either 89 mph or 93 mph depending on the run?
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.

GoSolar
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Re: LEAF Dyno Run

Tue Aug 23, 2011 8:23 am

I watched with great interest as they do a rolling/dyno tested on each LEAF as they come off the line at the Nissan Oppama factory. They take each car up to about 100 kpm with no tie downs! Saw one Juke really squirling (sp?) around for half a second but the driver got it all straightened out.

Most disappointing thing about the factory tour? NO PICTURES. ARGHHH!!!

GoSolar
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Re: LEAF Dyno Run

Tue Aug 23, 2011 8:26 am

BTW, where are the directions for uploading pictures? I see where you can give a URL link, but can't I just upload pics? I DO have some pictures from both the Factory tour and Nissan's global world HQ, and would like to post them with the details of both places.

Got a great screen shot showing all the local L2 an L3 charging stations in an area about the same size as Seattle Metro area. GREEN with envy on the availability of free charging stations all over the place.

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TomT
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Re: LEAF Dyno Run

Tue Aug 23, 2011 8:31 am

Some years back when we picked up our BMW at the factory in Munich on the EDP, we were given a factory tour that was incredible, and sure to give U.S. OSHA heart attacks! Among many other things, we were walking between the robotic chassis wielders with sparks flying right over our heads and no hard hats! One person even had a spark land in their hair. The tour was about three hours long and they actually encouraged us to take pictures. Due to demand and very small groups, the tours had to be scheduled months in advance (though if you were picking up a new car, they would fit you in regardless). Most fascinating!
GoSolar wrote:I watched with great interest as they do a rolling/dyno tested on each LEAF as they come off the line at the Nissan Oppama factory. They take each car up to about 100 kpm with no tie downs! Saw one Juke really squirling (sp?) around for half a second but the driver got it all straightened out.
Most disappointing thing about the factory tour? NO PICTURES. ARGHHH!!!
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

essaunders
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Re: LEAF Dyno Run

Tue Aug 23, 2011 8:49 am

Image

cool

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aqn
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Re: LEAF Dyno Run

Tue Aug 23, 2011 9:12 am

TLeaf wrote:So I finally caved and scheduled an appointment with a dyno for last Friday.
Thanks for doing that! Very interesting stuff!
TLeaf wrote:In both cases the car was in 'drive', but one involved mashing the accelerator while the other involved a neutral drop.
[...]
Though the lines do look a bit different between the two, I'd be highly dubious about both lines below 30mph as the wheels on the LEAF were definitely outpacing the dyno on both runs at this point. As much as I'd like to say that the LEAF simply had too much torque for the the dyno to keep up, I'm sure it was some combination of both high torque and the low rolling resistance tires.
Plus, dynos rarely produce measurements below 2000 rpm or so. A quick search of dyno graphs bears that out. The straight lines below 20 mph (about 2200 rpm) in your graph seem to be extrapolated values and not actual values.
Anna Nguyen

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