Argonne Downloadable Dynamometer Database - 2012 LEAF

I ran across a link to the report from the Argonne Advanced Powertrain Research Facility regarding the 2012 Nissan LEAF in, of all places, an AnandTech article about the Tesla Model S Controversy!

The really interesting (big PDF) report was this one - which contains all kinds of detailed information that people like Tony Williams and (Ingineer) Phil would love. It corroborates much of the range vs. temperature and other factors which have been much-discussed here.

A good (if really detailed) read...

ahagge said:

I ran across a link to the report from the Argonne Advanced Powertrain Research Facility...

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Very cool! Thanks!

One thing revealed in the presentation is that the 5-cycle EPA efficiency numbers for the 2012 LEAF are:

City: 111 MPGe
Highway: 99 MPGe
Combined: 105 MPGe

(Although I should note that their testing using the old method did NOT match the label results.)

Interesting.

The Leaf they used had some battery capacity degradation:21.7kW.h from the wall is well below what a new Leaf uses from turtle to 100%.

vegastar said:

The Leaf they used had some battery capacity degradation:21.7kW.h from the wall is well below what a new Leaf uses from turtle to 100%.

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But you'll notice that the cutoff voltage was significantly higher in the '12 LEAF that they tested. On page 20 you can see the difference. The '11 LEAF cutoff just over 290V (~3.02V/cell) while the '12 LEAF cutoff just under 310V (~3.21V/cell). I highly suspect that the '12 LEAF had one or more cell-pairs that were weaker than the rest.

In particular I found interesting how much more efficient the Prius is than the LEAF/Volt. Toyota really did a good job with the Prius - on the HWY cycle the Prius uses about ~150 Wh/mi compared to ~210 Wh/mi - on US06 it's ~260 Wh/mi vs ~340 Wh/mi. Put the LEAF drivetrain in a Prius shell and you'd turn a 75 mile range car into close to 100 mile range car...

vegastar said:

Interesting.

The Leaf they used had some battery capacity degradation:21.7kW.h from the wall is well below what a new Leaf uses from turtle to 100%.

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Yes, that's disappointing, but how would they have known the battery was significantly reduced unless they tested more than one?

Conclusions

- Established the energy consumption and range on standard drive cycles for the AVTA Leaf

- UDDS 233 AC Wh/mi and 92 miles

- US06 395 AC Wh/mi and 54 miles

- Characterized battery capacity and performance

- Established the accessory loads power levels

- In 20F weather the heater can double the energy consumption and cut the range in half

- In hot and sunny conditions, the air conditioning can increase the energy consumption by 25% with a hot cabin but the extra load is 5% or less for highway driving

- Characterized the heat power requirements to warm up the cabin 72F from 20F --> 3 to 6 kW

- Characterized the air conditioning requirements to cool the cabin to 72F from 95F with solar load --> 2 kW

Can anyone tell me the practical implications of the efficiency chart in the PDF (torque vs. mph chart)? Does it mean that pulse and glide might be more efficient for a Leaf, or am I not understanding it?

Stoaty said:

Can anyone tell me the practical implications of the efficiency chart in the PDF (torque vs. mph chart)? Does it mean that pulse and glide might be more efficient for a Leaf, or am I not understanding it?

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I think that is it. And I believe LEAFfan's experience confirms that pulse-and-glide is the best way to get great efficiency in the LEAF!

Their efficiency curves look quite similar to the ones from Nissan for the drivetrain, but these appear to include *everything*.

RegGuheert said:

I believe LEAFfan's experience confirms that pulse-and-glide is the best way to get great efficiency in the LEAF!

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It's a bit more trouble to drive that way, but tried it yesterday and got the least use of energy for my work commute ever (40 miles, 37.5% energy used, 75% beginning to 37.5% end by Gid meter). Of course, one day doesn't tell much as traffic conditions were good for that type of driving (about 40 MPH on the freeway). However, temp was only 55 degrees, which isn't optimal.

RegGuheert said:

Stoaty said:

Can anyone tell me the practical implications of the efficiency chart in the PDF (torque vs. mph chart)? Does it mean that pulse and glide might be more efficient for a Leaf, or am I not understanding it?

Click to expand...

I think that is it. And I believe LEAFfan's experience confirms that pulse-and-glide is the best way to get great efficiency in the LEAF!

Their efficiency curves look quite similar to the ones from Nissan for the drivetrain, but these appear to include *everything*.

Click to expand...

Can some explain "pulse and glide" please? Thanks

charge said:

Can some explain "pulse and glide" please? Thanks

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In the case of the Leaf, what I did was to have the energy usage shown on the Navigation screen. I press accelerator until I am using about 20 kw to get a good "pulse", then put the accelerator in the neutral position so I am neither using power nor getting any regen (power use as close to 0 kw as possible) to "glide". When I slow a bit too much, I give another "pulse" of 20 kw to get me up to the speed I want to go or a tad above. If you are driving fast (e.g., over 50-55 MPH) the aerodynamic drag loss will probably dwarf any efficiency gains, so best used along with moderate speeds.

Stoaty said:

...then put the accelerator in the neutral position so I am neither using power nor getting any regen...

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This can be done two different ways:

First, as Stoaty hints, in ECO mode the accelerator pedal position maps to drivetrain power, including both positive and negative powers. There is a position which corresponds to zero power, also known as coasting. Use the energy screen on the center console to help you find that point.

Alternatively, you can shift into neutral using the shifter. The normal way requires you to hold the shifter in neutral for about a second. The hypermiler way is to simply push the shifter into R while driving forward. The car will beep once and go into neutral. This takes a bit of nerve the first few times you do it, but it becomes natural after a while. So far there are no reports of a LEAF actually going into reverse while moving forward! (I heard a rumor about an Opel Ampera (Chevy Volt) going into reverse in Europe while traveling at a high rate of speed. I don't know if that turned out to be true or not!)

Have fun with pulse and glide!

RegGuheert said:

Alternatively, you can shift into neutral using the shifter. The normal way requires you to hold the shifter in neutral for about a second. The hypermiler way is to simply push the shifter into R while driving forward. The car will beep once and go into neutral. This takes a bit of nerve the first few times you do it, but it becomes natural after a while. So far there are no reports of a LEAF actually going into reverse while moving forward

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Actually, as I found out recently you need to be going a minimum speed for this technique to work. I forgot about it, shifted to "Reverse" once while going 3-5 miles per hour and the car abruptly stopped. I almost got hit from behind. Don't recall what the minimum speed is, but this is the only time it happened to me.

drees said:

In particular I found interesting how much more efficient the Prius is than the LEAF/Volt. Toyota really did a good job with the Prius - on the HWY cycle the Prius uses about ~150 Wh/mi compared to ~210 Wh/mi - on US06 it's ~260 Wh/mi vs ~340 Wh/mi. Put the LEAF drivetrain in a Prius shell and you'd turn a 75 mile range car into close to 100 mile range car...

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The Leaf is carrying an extra 400 pounds and the Volt is carrying an extra 750 pounds. Not sure there is that much difference between the Leaf and the Prius if you added/subtracted weight and equalized them. The Volt may have a more efficient shell than the Prius.

Stoaty said:

RegGuheert said:

Alternatively, you can shift into neutral using the shifter. The normal way requires you to hold the shifter in neutral for about a second. The hypermiler way is to simply push the shifter into R while driving forward. The car will beep once and go into neutral. This takes a bit of nerve the first few times you do it, but it becomes natural after a while. So far there are no reports of a LEAF actually going into reverse while moving forward

Click to expand...

Actually, as I found out recently you need to be going a minimum speed for this technique to work. I forgot about it, shifted to "Reverse" once while going 3-5 miles per hour and the car abruptly stopped. I almost got hit from behind. Don't recall what the minimum speed is, but this is the only time it happened to me.

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the speed is minimal and i would think not the best option for hypermiling