Edmunds.com Takes the LEAF to Turtle!

[LBCev]

As many of you know, Edmunds.com has a red 2011 Nissan Leaf in it's test fleet. Today they posted a video in which they took the Leaf to "turtle" before coasting to a stop after 132 miles. They accomplished this by driving relay at 35 mph on an undisclosed 7 mile loop in the desert.

Personally, I enjoy the antics and tongue and cheek commentary of Edmunds' staff.

Here's the link: http://blogs.insideline.com/roadtes...n-leaf-driving-it-to-the-bitter-end.html#more

 

[TRONZ]

That's a pretty good distance on one charge.

 

[GeekEV]

Based on their description of the LB, VLB and turtle, it seems pretty clear this was done in a car that hadn't had the firmware update. It would be VERY interesting to see them repeat the test post-update...

 

[TRONZ]

... also interesting that it took 26.08 kWh of power to fully charge it afterward.

 

[tps]

Hmm, 26 kWh was used to recharge a fully depleted battery pack. If the usable capacity is indeed 24 kWh, that would make the charging efficiency 92%. Sounds plausible.

 

[sdbonez]

we should ask them...

 

[LakeLeaf]

So is 132 miles officially the first entry in the LEAF mileage challenge?

 

[Boomer23]

... also interesting that it took 26.08 kWh of power to fully charge it afterward.

That's identical to what mine took to charge after I took it to turtle.

 

[LEAFfan]

One of the drivers said '35mph' was the optimum speed for mileage, but I thought I saw '38' somewhere. They would have exceeded 132 miles if they hadn't had to stop 4 times. Starting out uses the most, just like on an ICE car.

 

[Herm]

Great, they finally did it.. the first ones to do it and publish, with pictures so we know its real. I had been prodding them to do it for a few weeks and I'm glad they took the challenge.

I think its likely usable battery capacity is 24kwh, and charger efficiency is around 91%.. both very good numbers.. we will have to wait for better numbers until someone instruments the big battery cables.

 

[Herm]

One of the drivers said '35mph' was the optimum speed for mileage, but I thought I saw '38' somewhere.

Optimum is around 17mph, from the Tesla charts.. assuming the Leaf has similar parasitic losses.. aerodynamic losses can probably be discounted at these slow speeds.

Tesla charts: http://teslamotors.com/enthusiasts/blog/3859

 

[SanDust]

Hmm, 26 kWh was used to recharge a fully depleted battery pack. If the usable capacity is indeed 24 kWh, that would make the charging efficiency 92%. Sounds plausible.

Far more likely would be 85% charging efficiency and 22 kWh usable (167 wh\mile).

 

[DaveinOlyWA]

HAH!! i was right!! told you we only have 21½ KWH to use!!

 

[EVDRIVER]

One of the drivers said '35mph' was the optimum speed for mileage, but I thought I saw '38' somewhere. They would have exceeded 132 miles if they hadn't had to stop 4 times. Starting out uses the most, just like on an ICE car.

4 stops form 35 mph is not going to make a recordable difference on range, not one worth mentioning at all. Do the math of power consumption form 0-35 four times for seconds each time, don't forget to back out regen for slowing to a stop.

 

[DarkStar]

Hmm, 26 kWh was used to recharge a fully depleted battery pack. If the usable capacity is indeed 24 kWh, that would make the charging efficiency 92%. Sounds plausible.

The charger specifications put it at right about 90% so this sounds right on!

 

[EVDRIVER]

One of the drivers said '35mph' was the optimum speed for mileage, but I thought I saw '38' somewhere.

Optimum is around 17mph, from the Tesla charts.. assuming the Leaf has similar parasitic losses.. aerodynamic losses can probably be discounted at these slow speeds.

Tesla charts: http://teslamotors.com/enthusiasts/blog/3859

Irrelevant, depends on aerodynamics, gearing, motor design, weight, etc, etc. You can't compare two different vehicles with different drive systems.

 

[edatoakrun]

I tend to believe Nissan may have reported maximum range accurately long ago:

"Ideal driving conditions: 138 miles Speed: Constant 38 mph

Temperature: 68 degrees

Climate control: Off

Driving on a flat road at a constant 38 mph means less air resistance, and therefore less energy use. And at 68 degrees, there's no need for climate control, extending the range even further. The result: a range boost up to 138 miles."

The drive train efficiency chart from p 17 here:

http://www.electricauto.org/resource/resmgr/media/nissan_leaf_sae_2_11.pdf

Makes 38 mph a plausible LEAF optimal efficiency/wind resistance point.

So if someone wants to beat 132 miles, 38 mph may be a good speed to try.

Try it on a cooler day, so you won't have to crack the windows.

Do your research on optimal tire pressure.

Lighten the load as much as possible (this leaves me out of the competition) and make the fewest stops you can.

I would think cruise control would probably do a better job than a driver, unless a strong prevailing wind caused significant efficiency gains by varying ground speed, to match optimal "airspeed". IMO, it would be "cheating" to set the record by '"sailing", choosing a route with prevailing winds at a given time of day, and returning in low (or opposite) wind conditions.

Obviously, driving in a low-wind conditions would most accurately represent the "ideal".

 

[DaveinOlyWA]

The charger specifications put it at right about 90% so this sounds right on!

ok 90% for the charger, how much for the cooling system?

we have had ENDLESS discussion on this issue and many here have posted their thoughts and data on it.

i can tell you last month i got 3.63 miles for each KWH i got out of the wall. according to the Car, my charging efficiency is 75% and pretty much has been all along.

i am thinking i might get a bump on that as the weather gets warmer although not sure how that will work since it would imply the cooling system would need to work harder... but we shall see

 

[edatoakrun]

I've been following your comments, since I plan on using (mostly) L1 charging.

Since, the other likely variable, besides L1 charging is your presumed greater heater use than the "southerners", Have you calculated just how much heat/energy is lost by leaving a full tank of "heat-ant" when you park?

BTW, is there any way to turn off the heater element, and continue to use the heater, drawing down the stored thermal energy, to minimize this inefficiency?

Not the Ideal way to heat my garage, IMO...

The charger specifications put it at right about 90% so this sounds right on!

ok 90% for the charger, how much for the cooling system?

we have had ENDLESS discussion on this issue and many here have posted their thoughts and data on it.

i can tell you last month i got 3.63 miles for each KWH i got out of the wall. according to the Car, my charging efficiency is 75% and pretty much has been all along.

i am thinking i might get a bump on that as the weather gets warmer although not sure how that will work since it would imply the cooling system would need to work harder... but we shall see

 

[DaveinOlyWA]

BTW, is there any way to turn off the heater element, and continue to use the heater, drawing down the stored thermal energy, to minimize this inefficiency?

no. its not a heater, its a coolant system to cool off the charger. my garage usually does not get below about 50º even in winter on an average day of 35-40º.

but even during very warm days, there is very little if any noticeable heat being given off. the water circulating is under very little pressure so would guess the power used to be minimal.

i did charge for about 6 hours one day with the hood closed then opened it to see what kind of heat buildup there was and there was no appreciable amount there. the coolant hoses feel slightly above ambient temps but not hot or even really warm