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SageBrush

REJECT Fascism
May 7, 2015
12,508
15,526
New Mexico
Looking like it is not an edge case.
The throttling seems to start around 27 - 30 C battery temp and power is down to 22 kW at ~ 40 C. That is not hard to reach in a pack without thermal control.
Heck, summer and some driving should be enough for a large swath of the car buying world, even before they pull into a QC station.

Time will tell, but I've put my wager on this 40 kwh pack being the worse Nissan has ever made. And that is saying something.
 

dhanson865

Active Member
Feb 16, 2013
4,680
7,728
Knoxville, Tennessee
Isn't the throttle down to 20KW or so? If correct that is still x5 or x6 the speed my 3.x KW on board charger does. I drove back from NC on purchase of my used leaf 3 years ago with 2 chademo sessions and some Level 2 action. If the Level 2 could have been replaced with something 3x or 6x faster I'd be good with that even if that is throttled vs the first two chademo stops.
 
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EV-lutioin

Active Member
Apr 2, 2016
1,958
2,721
California
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renim

Active Member
Apr 6, 2013
1,801
2,255
Oz
this is what I had expected (for a fixed cell volume), increase in range capacity comes with a decrease in max charge rate.

we see it with GM Bolt vs Spark EV (strong TMS)
we see it with Renault ZOE (mild air refrigerant TMS)
we see it with Nissan LEAF (nil TMS, instead uses thermal mass philosophy)

the core reason is that the anode powder (carbon) has a strong inverse relationship between charge rate and safety (plating)
also faster charging carbon anode powder has less storage capacity than slower carbon. As the storage density improved with cathodes, the storage density of the anode becomes more critical.

the epitome of this was the
Japanese iMiEV with 10.5 kWH SCIB battery
vs
Japanese iMIEV with 16 kWH normal Li ion battery

(even Tesla has not improved charging rate much over the years (for a given cell volume)) the cell level density allowed a 85kWh to 90kWh improvement, and then squeezing more cells in allowed 90 to 100kWh). Did the transition from 85kWh to 90kWh come with an increase or a decrease in charge rate?

our instincts is to treat an increase in capacity as pro-rata with charge rate, but the reality is that, it really is a quid pro quo, one for the other.
 
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DurandalAI

Member
Dec 20, 2016
962
2,912
US
Judging from discussions on mynissanleaf the degradation of the 30kWh packs is even sharper than on the original 24kWh packs, yet they come with a longer battery warranty. I suspect Nissan will be eating some major warranty costs over the next few years. My 24kWh pack is just about to drop it’s 4 capacity bar, meaning it will have lost 33% if it’s original capacity, but I passed over the warranty period of 5 years a couple of months ago. If Nissan covers half or more of the cost of a replacement pack, I will do it, otherwise the Leaf will be useless except as a local grocery vehicle within a year or so. There are people in Arizona with 30KWh Leafs that have already lost 3 bars on their 2 year old cars, set to have a warranty replacement after this summer knocks them down once more. Poor engineering.
 

gaswalla

Model S,3,X.. CT with Austin delivery
Sep 23, 2012
3,455
3,847
San Diego
Hard to believe that Nissan managed to produce a worse car than the original Leaf..
Even more surprising is that they manage to keep selling that piece of junk after all these years - it shows the demand for EV vehicles (particularly from those that don't really understand the tech)
 

gaswalla

Model S,3,X.. CT with Austin delivery
Sep 23, 2012
3,455
3,847
San Diego
Judging from discussions on mynissanleaf the degradation of the 30kWh packs is even sharper than on the original 24kWh packs, yet they come with a longer battery warranty. I suspect Nissan will be eating some major warranty costs over the next few years. My 24kWh pack is just about to drop it’s 4 capacity bar, meaning it will have lost 33% if it’s original capacity, but I passed over the warranty period of 5 years a couple of months ago. If Nissan covers half or more of the cost of a replacement pack, I will do it, otherwise the Leaf will be useless except as a local grocery vehicle within a year or so. There are people in Arizona with 30KWh Leafs that have already lost 3 bars on their 2 year old cars, set to have a warranty replacement after this summer knocks them down once more. Poor engineering.

It looks like refurb batteries for the original leaf will be offered for 2800 in Japan - expecting US program in the future.
 

renim

Active Member
Apr 6, 2013
1,801
2,255
Oz
"Nissan will initially offer 24-kilowatt-hour refabricated batteries for 300,000 yen apiece, with plans to expand the lineup. Exchange costs for brand-new Nissan LEAF batteries are 650,000 yen for 24 kWh; 800,000 yen for 30 kWh; and 820,000 yen for 40 kWh."
Nissan starts exchange program for Nissan LEAF batteries in Japan

hmmmm

Realistically Nissan LEAF is likely to retake the global best seller crown for EV for first half 2018, and possibly even for calendar year 2018. why? GM researchers posit simple model to assist in balancing high energy density vs fast charging in EV design
its affordable enough to be voluntarily, globally sold and delivered.
 

SageBrush

REJECT Fascism
May 7, 2015
12,508
15,526
New Mexico
It used to be true (still might be -- unsure) that a battery bought out of pocket post new car warranty on the original battery was warranted for 5yr/60k miles. Even though the cost is high at ~ $6k USD, the warranty made it something to consider.

What warranty will be offered on the refurbs ? I know from years of reading about refurbs on Prius batteries that they performed miserably; I honestly doubt Nissan will do any better. And perhaps the most unpleasant part of this refurb plan is the possibility (likelihood, I think) that Nissan will be using refurbs in warranty repairs.
 
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dhanson865

Active Member
Feb 16, 2013
4,680
7,728
Knoxville, Tennessee
Sure, with two differences that cannot be ignored:

QC is often charged by the minute
You are typically not standing at the car twiddling your thumbs when at home

Price applied by the minute, very very good point. I'm a tightwad and the cost per kW in that situation would annoy me.

Charging at home isn't the consideration. I mentioned that I drove from NC to TN and had to charge at a public L2 when Chademo wasn't available. It might be different in your part of the world but Chademo units are sparse out here.

The 40 kWh battery would have let me hop past the L2 charging only at Chademo (not that I was giddy about the price of Chademo charging, it's always seemed overpriced to me).

Though EvGo dropped the session fee and now charge only by the minute. So it's not as overpriced now as it was the last time I had to use it.
 
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bro1999

Active Member
Apr 26, 2016
2,219
2,222
Maryland
No surprise, as Nissan is the king of cheap.
I already feel sorry for the poor '18 Leaf owner that trades in their old Leaf thinking they can now do a San Fran to LA drive in the middle of July in the 40 kWh Leaf. Odds are the Leaf's battery will be overheating before they can even do the first fast charge.
 

SageBrush

REJECT Fascism
May 7, 2015
12,508
15,526
New Mexico
Nissan says it just two people who have been reported the problem and that they are investigating it according to fully charge
They said something very similar when the first reports of fast battery degradation came to light.

Are any of us really surprised by findings of aggressive throttling due to thermal constraints though ? Nissan stuffs 40 kWh into a 24 kWh case without any active cooling -- and that means not even air.
 
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renim

Active Member
Apr 6, 2013
1,801
2,255
Oz
>ReddyLeaf

This link shows GM's philosophy which I strongly suspect mirrors Nissan's
GM researchers posit simple model to assist in balancing high energy density vs fast charging in EV design
upload_2018-3-27_10-25-21.png


I can't get beyond the paywall, but it seems the automotive majors (GM anyway) seem to model the car's use as range including 1 only recharge. The LEAF DC report from the UK is essentially from a guy delivering EVs, he is not representing EV use, but rather transport company use. (I hadn't realized that, but he is not the owner, he is similar in function to a dealer)

The Renault ZOE with TMS and LG cells also seem have even greater taper than Nissan LEAF 40kWh. Not that it matters when 22kW AC charging points is widely available for most ZOE buyers.
 

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