lorenfb
Posts: 1389
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 1:17 pm

ironmanco wrote:
lorenfb wrote:I've never stated nor implied that I had any actual data. I've always argued that actual Leaf battery cell characteristics/data were lacking to conclude or recommend any optimum charging mode.


Maybe not "optimum" but I think there is PLENTY of data and experience to recommend best practices for charging. Are we really shooting for the optimum or at least some basic methodology better than willly-nilly charging?


Agreed. My approach for the last 4 years is to always charge to 100% the previous early morning where the Leaf will be driven
within a few hours and limit the remaining Ahrs to about 18. I never QC to 100%. Typical charging times are about 10-12 minutes.
When not being used, the battery is left at 40% or less. Given the limited range of my 24kWh Leaf, any other charging approach would
be impractical. It's presently at 54K, 51 Ahrs, and one lost bar. Even on hot days (100F) here in SoCal, the battery has never exceeded
100-110F per LeafSpy/LeafDD.

The key point of this thread ideally would be to choose a practical charging mode for a desired range/battery life. Assuming a typical driving
case of 5 days a week with a daily full charge, that results in about 250 cycles per year. Using the typical capacity loss per battery cycle
presented here;

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

one finds that the worst case degradation per that data after about tens years (2500 cycles) is only about 15%. Others factors, e.g. heat,
dominate and result in significantly more degradation over that time period.
Last edited by lorenfb on Mon Nov 13, 2017 1:25 pm, edited 1 time in total.

edatoakrun
Posts: 4713
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 1:21 pm

ironmanco wrote:..I would imagine that the typical Leaf driver wants to know best practices for battery longevity...

Which Nissan provided in the 2011 LEAF owner's manual.

IMO, probably in order of priority:

...NISSAN recommends you use the following
driving and charging habits, where possible, to
help maximize the battery’s useful life:

. Avoid exposing a vehicle to ambient temperatures
above 120 F (49 C) for over 24
hours.

. Avoid storing a vehicle in temperatures
below -13 F (-25 C) for over 7 days.

. Avoid leaving your vehicle for over 14 days
where the Li-ion battery available charge
gauge reaches a zero or near zero (state of
charge).

. Allow the vehicle and Li-ion battery to cool
down after use before charging.

. Park/store your vehicle in cool locations out
of direct sunlight and away from heat
sources.

. Use the normal charging or trickle charging
methods to charge the Li-ion battery and
minimize the use of public Fast Charge or
Quick Charger.

. Avoid exceeding 70-80% state of charge
when using frequent (more than once per
week) public Fast Charge or Quick Charging.

. Allow the battery charge to be below at least
80% before charging.

. Moderate driving.

. Use of ECO mode.

. NISSAN recommends charging the batteries
using the long life mode unless the
vehicle is going to be driven a long distance.

See “Charging timer” in the “CH. Charging”
section.

. If vehicle will not be used for long period of
time:

- NISSAN recommends charging with
long life mode.
- Charge once every 3 months...

https://www.nissan-techinfo.com/refgh0v ... n-leaf.pdf

While Nissan dumbed down the LEAF by removing the "80%" charge option in 2014 (too many LEAF owners suffering from capacity loss anxiety were refusing to allow a full charge, and then complaining about their limited range...) I don't see why you'd have a major problem using a timer to limit charge level, when don't want a full charge.
Last edited by edatoakrun on Mon Nov 13, 2017 5:00 pm, edited 1 time in total.
no condition is permanent

arnis
Posts: 743
Joined: Sat Jan 23, 2016 3:21 pm
Delivery Date: 23 Jul 2014
Leaf Number: 015896
Location: Estonia, Europe

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 2:51 pm

ironmanco wrote:In other words, it is worth waiting around for complete and definitive testing that will guide us in an absolute approach to charging as compared to applying some general guidelines for charging based on what we currently know/understand?

To extend this logic - just because I don't know the absolute impact of leading a sedentary lifestyle doesn't mean I wait around being sedentary until proven otherwise :-)



Exactly. I've declared multiple times that keeping SOC down is better. The end.
"Well you don't know how much better it is, therefore you know sh*t" was the response :lol:
Therefore: "You look better than my ex" - "how much" - "more than enough" - "your evaluation is useless, I'm moving out".

How hard it is to swallow a hard fact that keeping Leaf at 60% SOC for a year will reduce range loss compared to Leaf that has been kept at 80% :roll:
Li-ion battery, not just Leaf.

Right, but the Leaf's 100% SOC voltage still maybe below where the actual problematic charging voltage occurs resulting in significant
degradation, e.g. 10%.

4.1V is not good. Until a new chemistry is invented that doesn't corrode at that high SOC. Up until now, all chemistries corrode slower at lower state of charge.
3.92V has been mentioned few times with no source. Usually something between 30-50% recommendation is given from battery manufacturers for cell storage. ALL of them.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

User avatar
LTLFTcomposite
Posts: 4337
Joined: Fri Apr 23, 2010 6:06 pm
Delivery Date: 10 Dec 2011
Leaf Number: 5926
Location: Boca Raton FL

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 4:49 pm

All those rules were followed on the car I spoke of, including not parking it for more than a week at temps below -138F. Any time the car was left for more than a couple days it was dutifully left half charged. As for routine daily charging it gets plugged in when it comes home in the evening.
Sorry if all that isn't good enough, but you really need to ask yourself if this a viable technology anyone will be interested in embracing if it comes with some ridiculous set of rules that need to be followed religiously or the thing self destructs. This vehicle has been well cared for and used thoughtfully. The problem is with the battery not the user.
LTL
White 2012 SV delivered 10 Dec 2011 returned 25 Nov 2014 replaced with stopgap ICE Sentra
[35 months] [35K miles] [9 Bars]
2013 Volt replaced after 36 months/30k miles with ICE Rogue

ironmanco
Posts: 115
Joined: Mon Dec 14, 2015 8:26 pm
Delivery Date: 25 Jan 2016
Location: Boulder, CO

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 6:06 pm

LTLFTcomposite wrote:All those rules were followed on the car I spoke of, including not parking it for more than a week at temps below -138F.


You'll have to share with us exactly where you would be parking the car with temps even close to -138F? All I know is wherever it is, it's a LONG way from Florida so I'm impressed if you actually drive your leaf there ;-)
2016 Nissan Leaf SL Deep Blue Pearl
Mfg 12/15 Del 1/16 30 Oct 2017 34172 mi Ahr 67.69 SOH 85% Hx 78.55%
Charging: evseupgrade L2 charging 30A circuit @ 24A shared garage heater circuit (ask me)

User avatar
LTLFTcomposite
Posts: 4337
Joined: Fri Apr 23, 2010 6:06 pm
Delivery Date: 10 Dec 2011
Leaf Number: 5926
Location: Boca Raton FL

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 6:49 pm

ironmanco wrote:
LTLFTcomposite wrote:All those rules were followed on the car I spoke of, including not parking it for more than a week at temps below -138F.


You'll have to share with us exactly where you would be parking the car with temps even close to -138F? All I know is wherever it is, it's a LONG way from Florida so I'm impressed if you actually drive your leaf there ;-)

Maybe I was hallucinating from the extreme cold... or maybe: Last edited by edatoakrun on Mon Nov 13, 2017 8:00 pm, edited 1 time in total.

:lol:
LTL
White 2012 SV delivered 10 Dec 2011 returned 25 Nov 2014 replaced with stopgap ICE Sentra
[35 months] [35K miles] [9 Bars]
2013 Volt replaced after 36 months/30k miles with ICE Rogue

lorenfb
Posts: 1389
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 7:29 pm

lorenfb wrote:
ironmanco wrote:
lorenfb wrote:I've never stated nor implied that I had any actual data. I've always argued that actual Leaf battery cell characteristics/data were lacking to conclude or recommend any optimum charging mode.


Maybe not "optimum" but I think there is PLENTY of data and experience to recommend best practices for charging. Are we really shooting for the optimum or at least some basic methodology better than willly-nilly charging?


Agreed. My approach for the last 4 years is to always charge to 100% the previous early morning where the Leaf will be driven
within a few hours and limit the remaining Ahrs to about 18. I never QC to 100%. Typical charging times are about 10-12 minutes.
When not being used, the battery is left at 40% or less. Given the limited range of my 24kWh Leaf, any other charging approach would
be impractical. It's presently at 54K, 51 Ahrs, and one lost bar. Even on hot days (100F) here in SoCal, the battery has never exceeded
100-110F per LeafSpy/LeafDD.

The key point of this thread ideally would be to choose a practical charging mode for a desired range/battery life. Assuming a typical driving
case of 5 days a week with a daily full charge, that results in about 250 cycles per year. Using the typical capacity loss per battery cycle
presented here;

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

one finds that the worst case degradation per that data after about tens years (2500 cycles) is only about 15%. Others factors, e.g. heat,
dominate and result in significantly more degradation over that time period.


Further analysis of the linked graphic of degradation based on a generic Li ion battery for typical charging cycles used

Image

After about 10 years (2500 cycles) the difference in degradation between the 100-40% and the 85-25% SOCs is only about 3%,
or about .30% per year. Now should a Leaf owner overly focus on what charging cycle is optimum to minimize degradation
or on what factors related to battery heat should be of more concern, e.g. excessive QC on a hot day?

Oils4AsphaultOnly
Gold Member
Posts: 267
Joined: Sat Oct 10, 2015 4:09 pm
Delivery Date: 20 Nov 2016
Leaf Number: 313890
Location: Arcadia, CA

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 8:28 pm

lorenfb wrote:
Further analysis of the linked graphic of degradation based on a generic Li ion battery for typical charging cycles used

Image

After about 10 years (2500 cycles) the difference in degradation between the 100-40% and the 85-25% SOCs is only about 3%,
or about .30% per year. Now should a Leaf owner overly focus on what charging cycle is optimum to minimize degradation
or on what factors related to battery heat should be of more concern, e.g. excessive QC on a hot day?


20C == 68F

Combine that chart with Table 3, and you'll see it's all downhill from there as the temp increases to the equivalent of our region. Also, I would go through 2500 cycles (that chart is charting partial charge cycles, not full charge cycles) in just 5 years (more frequent charges as the capacity degrades). Lastly, you chose a data point that looked to be an anomaly. @ 2200 cycles, the difference was actually 4% for a 60% DoD. It's actually 5% difference if looking at the 50% DoD lines. Since we know a shallower DoD cycle is better for battery life, the [Edit:] less severe degradation must be attributable to the lower SOC that the battery is charged to. So revising the calculations for 2200 cycles, 50% DoD, and 5 year span, that's 1% (@ 68F peak temp) per year due to simply charging to a lower SoC.

BUT all of that misses the forest for the trees! The red, black, and dark blue lines ALL have worse battery health (regardless of the DoD charge cycle) than even the heaviest DoD cycle (green line @ 60%) which only charged to 85%.

For practical purposes, some of us would like to extend the life of the battery where we can (limiting the battery temp during charging isn't within my control in my use cases, and potentially others as well).

In light of this, and the fact that you don't have data to claim otherwise, it is a disservice to claim that charging to 100% is no worse than charging to 90% as long someone uses the car right away. For commuters that can't control where they park or when they charge (during the day), the SoC they leave at absolutely makes a difference.
[2013 leaf traded for 2016 leaf S30:
build date: Sep '16 :: purchased: Nov '16
1 May 2017 - 7300 miles & 363 GIDs
6 Sep 2017 - 13k miles & 359 GIDs
26 Oct 2017 - 15.5k miles & 344 GIDs]

johnlocke
Posts: 173
Joined: Fri Jan 08, 2016 3:47 pm
Delivery Date: 14 Dec 2015
Leaf Number: 300582

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 10:49 pm

Oils4AsphaultOnly wrote:
lorenfb wrote:
Further analysis of the linked graphic of degradation based on a generic Li ion battery for typical charging cycles used

Image

After about 10 years (2500 cycles) the difference in degradation between the 100-40% and the 85-25% SOCs is only about 3%,
or about .30% per year. Now should a Leaf owner overly focus on what charging cycle is optimum to minimize degradation
or on what factors related to battery heat should be of more concern, e.g. excessive QC on a hot day?


20C == 68F

Combine that chart with Table 3, and you'll see it's all downhill from there as the temp increases to the equivalent of our region. Also, I would go through 2500 cycles (that chart is charting partial charge cycles, not full charge cycles) in just 5 years (more frequent charges as the capacity degrades). Lastly, you chose a data point that looked to be an anomaly. @ 2200 cycles, the difference was actually 4% for a 60% DoD. It's actually 5% difference if looking at the 50% DoD lines. Since we know a shallower DoD cycle is better for battery life, the [Edit:] less severe degradation must be attributable to the lower SOC that the battery is charged to. So revising the calculations for 2200 cycles, 50% DoD, and 5 year span, that's 1% (@ 68F peak temp) per year due to simply charging to a lower SoC.

BUT all of that misses the forest for the trees! The red, black, and dark blue lines ALL have worse battery health (regardless of the DoD charge cycle) than even the heaviest DoD cycle (green line @ 60%) which only charged to 85%.

For practical purposes, some of us would like to extend the life of the battery where we can (limiting the battery temp during charging isn't within my control in my use cases, and potentially others as well).

In light of this, and the fact that you don't have data to claim otherwise, it is a disservice to claim that charging to 100% is no worse than charging to 90% as long someone uses the car right away. For commuters that can't control where they park or when they charge (during the day), the SoC they leave at absolutely makes a difference.

You're still missing the big point of that chart. After 5000 cycles under the most strenuous conditions, you would still have 78% of the capacity! 5000 cycles represents at least 14 years of operation. Short cycling the battery is better for the battery but even cycling between 25% and 85% only adds about 10% to the capacity at 5000 cycles. Leaf batteries fail within five or six years Not fifteen. Charging habits are not the problem.
Jamul, CA
San Diego East County

Oils4AsphaultOnly
Gold Member
Posts: 267
Joined: Sat Oct 10, 2015 4:09 pm
Delivery Date: 20 Nov 2016
Leaf Number: 313890
Location: Arcadia, CA

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Nov 13, 2017 11:07 pm

johnlocke wrote:
Oils4AsphaultOnly wrote:
lorenfb wrote:
Further analysis of the linked graphic of degradation based on a generic Li ion battery for typical charging cycles used

Image

After about 10 years (2500 cycles) the difference in degradation between the 100-40% and the 85-25% SOCs is only about 3%,
or about .30% per year. Now should a Leaf owner overly focus on what charging cycle is optimum to minimize degradation
or on what factors related to battery heat should be of more concern, e.g. excessive QC on a hot day?


20C == 68F

Combine that chart with Table 3, and you'll see it's all downhill from there as the temp increases to the equivalent of our region. Also, I would go through 2500 cycles (that chart is charting partial charge cycles, not full charge cycles) in just 5 years (more frequent charges as the capacity degrades). Lastly, you chose a data point that looked to be an anomaly. @ 2200 cycles, the difference was actually 4% for a 60% DoD. It's actually 5% difference if looking at the 50% DoD lines. Since we know a shallower DoD cycle is better for battery life, the [Edit:] less severe degradation must be attributable to the lower SOC that the battery is charged to. So revising the calculations for 2200 cycles, 50% DoD, and 5 year span, that's 1% (@ 68F peak temp) per year due to simply charging to a lower SoC.

BUT all of that misses the forest for the trees! The red, black, and dark blue lines ALL have worse battery health (regardless of the DoD charge cycle) than even the heaviest DoD cycle (green line @ 60%) which only charged to 85%.

For practical purposes, some of us would like to extend the life of the battery where we can (limiting the battery temp during charging isn't within my control in my use cases, and potentially others as well).

In light of this, and the fact that you don't have data to claim otherwise, it is a disservice to claim that charging to 100% is no worse than charging to 90% as long someone uses the car right away. For commuters that can't control where they park or when they charge (during the day), the SoC they leave at absolutely makes a difference.


You're still missing the big point of that chart. After 5000 cycles under the most strenuous conditions, you would still have 78% of the capacity! 5000 cycles represents at least 14 years of operation. Short cycling the battery is better for the battery but even cycling between 25% and 85% only adds about 10% to the capacity at 5000 cycles. Leaf batteries fail within five or six years Not fifteen. Charging habits are not the problem.


I don't think I'm missing the point, since the chart is for 20C (only places like Norway would never exceed that temp), which is pretty much ideal operating temp for any chemistry cell. The only "streneous" condition was the depth-of-duty cycle (worst case being 60%).

"Excess" heat, whether due to charging, driving, or just ambient temps would just accelerate the degradation. That would bring the laboratory cell samples inline with what the Leaf batteries experience. The point of the chart was to show that SOC matters. Even more so when you can't control the heat input into the cells.
[2013 leaf traded for 2016 leaf S30:
build date: Sep '16 :: purchased: Nov '16
1 May 2017 - 7300 miles & 363 GIDs
6 Sep 2017 - 13k miles & 359 GIDs
26 Oct 2017 - 15.5k miles & 344 GIDs]

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