Edmunds.com Takes the LEAF to Turtle!

[Coffee_Slurry]

In the Edmunds test in particular, I was surprised by how little warning the LEAF gives:

112.4 miles, DTE meter blinks "20" miles, two bars.
122.0 miles, one bar of electricity, "- - -" miles
130.0 miles, zero bars, Tortoise light, reduced speed
131.2 miles, red triangle
132.0 miles, dead

To me, this is pretty FAST notice. I get the yellow "Low Fuel" light on my car with still a good 50+ miles still in the tank.
People who tend to run close to empty will cure themselves of that habit quickly in the Leaf.

Tortoise light here means "pull over now", with only 2 miles of absolute range remaining. Yow.

 

[edatoakrun]

I am asking you about how you (and the LEAF) are accounting for the energy usage by the (separate) cabin heating system, in your charge efficiency calculations. Since you may be using it more than others, this could be a significant factor in your lower charge efficiency findings.

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

 

[JasonT]

You can see it in a few places, but it is clearest here - 5 trees!

 

[Herm]

Hah!.. I'm still glad they did it.. regarding the battery capacity, I wont be happy until someone actually measures it. At the battery.

 

[AndyH]

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).

Nissan says 24kWh usable. AESC says 24kWh usable. Users here have used 24kWh and now Edmunds has. There will be no long-form capacity certificate...

 

[Boomer23]

"Professional driver on closed course - Do Not Attempt!" :lol:

 

[evnow]

Nissan says 24kWh usable. AESC says 24kWh usable. Users here have used 24kWh and now Edmunds has. There will be no long-form capacity certificate...

I think the term "usable" itself is a little murky. As I explained in another thread, whetever Leaf is using to calculate miles/kwh is not 24 kwh. That is more like 21 to 22kwh.

The whatever could be at the point where energy leaves the battery (seems to be the right place to measure "usable" energy) - or might be some kind of calculation based on consumption at the motor and accessories less regen, in which case it can't be directly equated to any kind of "usable" capacity.

Or there is some problem with Leaf m/kwh number (quite likely given admittendly wrong Carwings m/kwh number).

 

[planet4ever]

As I explained in another thread, whatever Leaf is using to calculate miles/kwh is not 24 kwh. That is more like 21 to 22kwh.

Huh? Can you explain that statement? I would surely think miles/kwh would be calculated by dividing miles traveled by kwhs used, and the answer would be the same whether the usable capacity was 10 kwh or 100 kwh. You do make a good point on "used, though:

The whatever could be at the point where energy leaves the battery (seems to be the right place to measure "usable" energy) - or might be some kind of calculation based on consumption at the motor and accessories less regen, in which case it can't be directly equated to any kind of "usable" capacity.

I'm still leaning toward the latter, and I don't think it is necessarily an error in their calculation. As I have said before, if you forget about trying to extrapolate usable capacity, and focus only on drive efficiency of the LEAF, then you want to eliminate extraneous variables like heating and lights. The true drive efficiency is (miles driven) / ( (energy used by the motor) - (regen energy) ).

The only debate might be whether regen energy should be as measured coming out of the motor or down-rated based on expected losses going to, and returning from, the battery.

Ray

 

[evnow]

You do make a good point on "used, though:

There you have the answer. Wherever Leaf measures the "used" kwh, from start to finish isn't 24 kwh.

As I have said before, if you forget about trying to extrapolate usable capacity, and focus only on drive efficiency of the LEAF, then you want to eliminate extraneous variables like heating and lights. The true drive efficiency is (miles driven) / ( (energy used by the motor) - (regen energy) ).

That is not what Leaf does. Heating clearly affects efficiency as I've seen on umpteen days.

 

[LeafTalk]

Whilst they got good mileage, going around a track at 35mph is hardly reflective of real world inner city driving. The stop/start, stop/start cycle amongst city traffic will give you a lower mileage even if you stick to 35mph. That should be made clear otherwise you will get people complaining that they couldn't achieve the same result. Class action lawsuit against Edmunds? :lol:

 

[AndyH]

Nissan says 24kWh usable. AESC says 24kWh usable. Users here have used 24kWh and now Edmunds has. There will be no long-form capacity certificate...

I think the term "usable" itself is a little murky. As I explained in another thread, whetever Leaf is using to calculate miles/kwh is not 24 kwh. That is more like 21 to 22kwh.

No worries. I'm looking at the problem from a battery capacity perspective - that applies best to absolute range and the 'fuel gauge' bars which give a 'cave etching' of state of charge.

I'm not addressing at all the voodoo that goes into the range calcs. After reading about experience in the field, I'm expecting to find a container under the hood for chalk dust and chicken feet. :lol:

The whatever could be at the point where energy leaves the battery (seems to be the right place to measure "usable" energy) - or might be some kind of calculation based on consumption at the motor and accessories less regen, in which case it can't be directly equated to any kind of "usable" capacity.

Or there is some problem with Leaf m/kwh number (quite likely given admittendly wrong Carwings m/kwh number).

This is part of the reason for confusion on the forum, me thinks. We have the hard scientific/laws of physics "total battery capacity" based on the cells inside the battery box. And then we have the range guestimates and Carwings numbers. We also appear to have fuzzy consumption numbers from the Blink EVSE.

Capacity is capacity - but there are way too many variables in the 'other' side of the puzzle...