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OrientExpress
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Re: Everything you might want to know about the '18 LEAF engineering

Thu Mar 15, 2018 6:26 pm

LeftieBiker wrote:Change "design flaw" to just "flaw" and it's an observation, not a conclusion. Mayne it is a manufacturing issue, for all the difference it seems to make. You can think of this as an 'occasional lemon' problem, but so far we have only one, AFAIK, person posting good numbers for a 30kh pack. The rest of the ones posted here show rapid degradation.


Sorry, BikerBoy, no offense, but I recommend you hold your fire and let that situation come to conclusion. You may find yourself barking up the wrong tree.
2018 LEAF SL
Gun Metalic
Delivery April 10 2018

Prior LEAF:
2014 LEAF SV
Ocean Blue
Delivery May 23 2014
50,000+ miles - all 12 bars - Same range as new - No warranty issues ever!

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Nubo
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Re: Everything you might want to know about the '18 LEAF engineering

Thu Mar 15, 2018 6:53 pm

DaveinOlyWA wrote:
LeftieBiker wrote:I didn't post any "conclusions." Why the variance in SOH among drivers in the same region? We don't know. The drivers don't know either, and they aren't doing anything that Nissan has warned them not to do. It may be heating related to charging, but we don't know that yet. The 30kwh packs have a serious design flaw that appears to be causing excess degradation in a majority of the cars. That is Nissan's fault, not the drivers' fault.



cars? cellphones? or any other device where we are required to manage the battery? It used to be simply low quality batteries. Not so much anymore.

The reality is we have traded battery longevity for convenience. We accept that unknowingly then blame whoever when our cellphones can't make it without a boost in the middle of the day 6 months down the line. But why? Because the battery used to go to bed at 60% before being recharged overnight to full for the next day .

We didn't understand the importance of avoiding 100% needlessly because it was simply much easier to plug it in at night and forget about it till morning. Way too much of a hassle to plug it in for an hour a few times a day.... WAY too much hassle.


I think Leftie's point here can't be over-emphasized. The behaviors you cite (without debating their harms or merits), are something Nissan does not recommend for, or against. If one cannot expect acceptable durability by using the vehicle in a convenient fashion, then it is incumbent upon Nissan to explain how to achieve that durability.

And yet they took away the one tool that could be used to reliably terminate charge before 100%. So outside of blatant abuse, I can't reasonably assign blame to everyday LEAF drivers.
I noticed you're still working with polymers.

SageBrush
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Re: Everything you might want to know about the '18 LEAF engineering

Sun Mar 18, 2018 11:52 am

Nubo wrote:[The behaviors you cite (without debating their harms or merits), are something Nissan does not recommend for, or against. If one cannot expect acceptable durability by using the vehicle in a convenient fashion, then it is incumbent upon Nissan to explain how to achieve that durability.

Set a timer to finish charging shortly before use.

While most of Dave's pronouncements are the stuff of speculation from an anecdote or three, it just makes sense to not have the battery stew in the heat at high SOC.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
3/2018: 58 Ahr, 28k miles

GRA
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Re: Everything you might want to know about the '18 LEAF engineering

Sun Mar 18, 2018 4:34 pm

I see the battery capacity warranty is still based on undefined 'bars' (Pg. 8): https://owners.nissanusa.com/content/techpub/ManualsAndGuides/LEAF/2018/2018-LEAF-warranty-booklet.pdf

Unlike every other BEV manufacturer (at least all those I'm aware of), Nissan continues to be unwilling to provide a hard value for their capacity warranty, which tells us that nothing has changed in their business practices.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

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Re: Everything you might want to know about the '18 LEAF engineering

Mon Mar 19, 2018 4:30 pm

Via GCR:
Battery life of 2018 Nissan Leaf vs 2017 Chevy Bolt EV electric cars: what manuals suggest
https://www.greencarreports.com/news/1115815_battery-life-of-2018-nissan-leaf-vs-2017-chevy-bolt-ev-electric-cars-what-manuals-suggest
Those of you who've been around here awhile know the all the procedures/inconveniences Nissan recommends to make the battery last longer, but here they're summarized and compared with the procedures recommended by GM for the (liquid-cooled TMS) Volt/Bolt.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

scottf200
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Re: Everything you might want to know about the '18 LEAF engineering

Mon Mar 19, 2018 4:49 pm

SageBrush wrote:10% degradation per 500 cycles. Environmental details were not mentioned
Ouch
Silver lining: at least this time around Nissan is being honest that the battery willl have poor longevity.


To put the cycles number in some different perspectives. Some Tesla-like battery numbers:

>>>>>>>>>>>>>>>>>>>>>
From the following article on batteries "similar" to what Tesla is using.

Divide those number of cycles by 365 or 300 or whatever number of days per year you want. Pretty long.

"500 cycles? But that’s (relatively) low! Yes. But what is not shown on the spec sheet is that when you partially charge and discharge, degradation of the battery capacity is reduced. Thus, you can do over
40 000 charge/discharge cycles when going from 30% to 70% only. Or over
35 000 charge/discharge cycles from 20% to 80%;
28 000 cycles from 10% to 90%;
15 000 cycles from 8% to 92%,
07 500 cylces from 6% to 94%, and the capacity reduction goes faster and faster, finally reaching
00 500 cycles when recharging from 0% to 100%."

http://blog.evandmore.com/lets-talk-abo ... ncr18650b/
<<<<<<<<<<<<<<<<<<<<<
100K EV miles and 80% EV usage
Volt = 53+ mile BEV up to 100 MPH, then 40 MPG hybrid with a 9 gal gas tank
'17 Tesla Model X 100D 'used'| RIP '16 P90DL Sig | 2011 Volt kid2 | 2016 for wife | 2012 kid1

SageBrush
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Re: Everything you might want to know about the '18 LEAF engineering

Mon Mar 19, 2018 5:04 pm

scottf200 wrote:
SageBrush wrote:10% degradation per 500 cycles. Environmental details were not mentioned
Ouch
Silver lining: at least this time around Nissan is being honest that the battery willl have poor longevity.


To put the cycles number in some different perspectives. Some Tesla-like battery numbers:

>>>>>>>>>>>>>>>>>>>>>
From the following article on batteries "similar" to what Tesla is using.

Divide those number of cycles by 365 or 300 or whatever number of days per year you want. Pretty long.

"500 cycles? But that’s (relatively) low! Yes. But what is not shown on the spec sheet is that when you partially charge and discharge, degradation of the battery capacity is reduced. Thus, you can do over
40 000 charge/discharge cycles when going from 30% to 70% only. Or over
35 000 charge/discharge cycles from 20% to 80%;
28 000 cycles from 10% to 90%;
15 000 cycles from 8% to 92%,
07 500 cylces from 6% to 94%, and the capacity reduction goes faster and faster, finally reaching
00 500 cycles when recharging from 0% to 100%."

http://blog.evandmore.com/lets-talk-abo ... ncr18650b/
<<<<<<<<<<<<<<<<<<<<<


You are right that DoD affects battery longevity but you cannot just perform simple division from the test data to infer how long the battery will last in a car. E.g., a test cycle that returns 40k cycles is NOT going to last 100 years. All we really know from the data is that the LEAF cells are no where near as robust as competitors.

A better way to look at this data is that a cell that lasts 500 cycles in a particular environment and use profile will last ~ half as long as a cell that lasts 1000 cycles in the same environment and use profile. And that evaluation is also suspect because these cells do not exist in isolation once they are packaged into modules and into a battery case.

For the LEAF we have a quadruple wammy: inferior cell, in inferior packaging, with higher max voltage, under higher thermal stresses.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
3/2018: 58 Ahr, 28k miles

WetEV
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Re: Everything you might want to know about the '18 LEAF engineering

Tue Mar 20, 2018 8:00 am

SageBrush wrote:A better way to look at this data is that a cell that lasts 500 cycles in a particular environment and use profile will last ~ half as long as a cell that lasts 1000 cycles in the same environment and use profile.


A cell with 500 cycles life and 10 year calendar life will outlast a cell with 1000 cycles life and a 2 year calendar life, at 100 cycles per year...
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scottf200
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Re: Everything you might want to know about the '18 LEAF engineering

Sat Mar 24, 2018 7:20 am

OrientExpress wrote:https://pushevs.com/2017/09/08/lg-chem-will-introduce-ncm-811-battery-cells-evs-next-year/


Various articles and forums are 'trashing' the 22 kW DC 'fast charging' of the new LEAF. 2nd DCFC 27kW; 3rd+ 22kW

https://insideevs.com/watch-2018-nissan ... ng-issues/

https://speakev.com/threads/worried-abo ... 025/page-3
100K EV miles and 80% EV usage
Volt = 53+ mile BEV up to 100 MPH, then 40 MPG hybrid with a 9 gal gas tank
'17 Tesla Model X 100D 'used'| RIP '16 P90DL Sig | 2011 Volt kid2 | 2016 for wife | 2012 kid1

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OrientExpress
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Re: Everything you might want to know about the '18 LEAF engineering

Sat Mar 24, 2018 8:41 am

scottf200 wrote:Various articles and forums are 'trashing' the 22 kW DC 'fast charging' of the new LEAF. 2nd DCFC 27kW; 3rd+ 22kW


As with most enthusiast sites, there is lots of speculation, combined a shortage of interpretive abilities that make for questionable claims that get echo-chambered in the blogosphere.

DCFC EVSEs do throttle the charge rate, I've seen rates as low as 8kW during a charge session, and it is not uncommon to see rates in the 20kW and lower during a session.

In 2 weeks I will have an '18 for a week or so to evaluate the "Drive the Arc" charging network in Northern California. We plan to drive the entire network from Monterey to Lake Tahoe and back to get some background on long-distance driving with multiple DCFC charge events in various driving situations, (urban, flat road freeway, hilly freeway, mountain driving, and long downhill freeway).
2018 LEAF SL
Gun Metalic
Delivery April 10 2018

Prior LEAF:
2014 LEAF SV
Ocean Blue
Delivery May 23 2014
50,000+ miles - all 12 bars - Same range as new - No warranty issues ever!

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