SageBrush
Posts: 5375
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

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

Thu Nov 09, 2017 10:08 pm

lorenfb wrote:
Of greater concern should be excessive battery temperature the result of ambient, charging current (QC), and motor current while driving.
No doubt you say that based on randomized, large scale, longitudinal studies
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

lorenfb
Posts: 2474
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

Thu Nov 09, 2017 10:16 pm

Oils4AsphaultOnly wrote: Would you agree that parking the car at 80% SOC is worse than parking it at 60% SOC? If we can agree on that, then it's trivial to see what SOC you have to start your day with to get to either of those situations.
Not really. Were are data to conclude that? Just because one may obtain data that indicates remaining a 100% SOC for very lengthy
time periods results in significant degradation over time, it's unscientific to assume the same long term effect occurs for lower SOC
deltas without supporting data.
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

lorenfb
Posts: 2474
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

Thu Nov 09, 2017 10:33 pm

SageBrush wrote:
lorenfb wrote:
Of greater concern should be excessive battery temperature the result of ambient, charging current (QC), and motor current while driving.
No doubt you say that based on randomized, large scale, longitudinal studies
Right. Have you missed the one (effect of temperature on degradation) done by a forum member which was fairly exhaustive.
I really doubt that, though, and assume you're attempting to be provocative or joking, right? I give you more credit at being
informed than what you posted.
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

Oils4AsphaultOnly
Posts: 777
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

Thu Nov 09, 2017 11:40 pm

lorenfb wrote:
Oils4AsphaultOnly wrote: Would you agree that parking the car at 80% SOC is worse than parking it at 60% SOC? If we can agree on that, then it's trivial to see what SOC you have to start your day with to get to either of those situations.
Not really. Were are data to conclude that? Just because one may obtain data that indicates remaining a 100% SOC for very lengthy
time periods results in significant degradation over time, it's unscientific to assume the same long term effect occurs for lower SOC
deltas without supporting data.
It might be "unscientific" to you, but it's perfectly valid to extrapolate using inductive reasoning when dealing with chemical responses within a value range for a fixed parameter.

Here's the summary with supporting evidence charting battery degradation with different states of charge, as well as different temperatures: http://batteryuniversity.com/learn/arti ... _batteries (note table 3, figure 5, and figure 6)

A good scientific study controls for variables in its test group, showing trends that supports/refutes its hypothesis. Not every situation will necessarily be tested.

A good engineer extrapolates off of the conclusions of those studies to draw reasonable conclusions in the absence of supporting evidence.

We know that keeping a battery at a high state of charge is worse for that battery than keeping it at a lower state of charge. We know that higher temps degrades a battery faster than lower temps. Is it REALLY necessary to have a full study done to conclude that a battery sitting parked under the sun at 80% SOC will degrade faster than the same one sitting at 70% (or even 60%) SOC?!
:: Model 3 LR :: acquired 9 May '18
:: Leaf S30 :: build date: Sep '16 :: purchased: Nov '16
100% Zero transportation emissions (except when I walk) and loving it!

SageBrush
Posts: 5375
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

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

Thu Nov 09, 2017 11:58 pm

lorenfb wrote:
SageBrush wrote:
lorenfb wrote:
Of greater concern should be excessive battery temperature the result of ambient, charging current (QC), and motor current while driving.
No doubt you say that based on randomized, large scale, longitudinal studies
Right. Have you missed the one (effect of temperature on degradation) done by a forum member which was fairly exhaustive.
I really doubt that, though, and assume you're attempting to be provocative or joking, right? I give you more credit at being
informed than what you posted.
Wait ...
You are drawing conclusions for all LEAFs based on ONE 'extensively documented' anecdote ?
That makes you and DaveInOly birds of a feather.

I actually agree with with your conclusions, but you are falling on your own petard.
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

arnis
Posts: 1026
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

Fri Nov 10, 2017 6:12 am

It's not that complicated. There are Leafs, incl 30kWh Leafs, that have excellent SOH no matter how
deep are the cycles, how many cycles there are, how far are they charged (80% or 100%), QC or not.
Without any other data it is possible to conclude with high degree of certainty that ALL
these factors do not play a major role in rapid degradation as there are hardly any rapid degraders
in moderate climates. They play some role, but at expected rates, giving battery a 10+ year or 200Mm lifetime.
We do have lots and lots of data, that temperature above some point plays a MAJOR role in degradation
above expected rates. I'm living proof that 5 bars is not enough for 2014+ Leafs.
Other than lowering overall cell voltage over calendar life, there is absolutely nothing that could be done
that could slow down the process (with the exception of lowering pack temperature, though playing
with "when to charge, when to discharge" doesn't lower overall temp) of that rapid degradation.

Luckily, Jeff's data and his personal recommendation for Li-ion battery storage (general, not just Leaf) clearly
state that keeping cell voltage lower does actually reduce parasitic reactions at all temperatures.
And it is not 80%. It's 50% or less. Therefore going closer to that is the only thing that could reduce the problem.
If that doesn't do that, nothing will.

Disproving that with no new data is not scientific.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

lorenfb
Posts: 2474
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

Fri Nov 10, 2017 9:06 am

arnis wrote: Luckily, Jeff's data and his personal recommendation for Li-ion battery storage (general, not just Leaf) clearly
state that keeping cell voltage lower does actually reduce parasitic reactions at all temperatures.
And it is not 80%. It's 50% or less. Therefore going closer to that is the only thing that could reduce the problem.
If that doesn't do that, nothing will.

Disproving that with no new data is not scientific.
Again, the time factor in the various states is being ignored, and that's NOT scientific!
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

lorenfb
Posts: 2474
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

Fri Nov 10, 2017 9:19 am

Oils4AsphaultOnly wrote:[
A good engineer extrapolates off of the conclusions of those studies to draw reasonable conclusions in the absence of supporting evidence.
That assumes the relationship is continuous and linear. You really don't know the overall relationship between SOC and degradation.
Does it become exponential as SOC approaches 100% and insignificant below 90-95%?
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

Oils4AsphaultOnly
Posts: 777
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

Fri Nov 10, 2017 9:50 am

lorenfb wrote:
Oils4AsphaultOnly wrote:[
A good engineer extrapolates off of the conclusions of those studies to draw reasonable conclusions in the absence of supporting evidence.
That assumes the relationship is continuous and linear. You really don't know the overall relationship between SOC and degradation.
Does it become exponential as SOC approaches 100% and insignificant below 90-95%?
Refer to figures 6 from the link I've posted earlier. Note the difference between the light-blue and the navy-blue lines. Both are 50% DoD duty cycles, but one started at 100%, while the other started at 75%.
:: Model 3 LR :: acquired 9 May '18
:: Leaf S30 :: build date: Sep '16 :: purchased: Nov '16
100% Zero transportation emissions (except when I walk) and loving it!

arnis
Posts: 1026
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

Fri Nov 10, 2017 3:20 pm

lorenfb wrote: Again, the time factor in the various states is being ignored, and that's NOT scientific!
keeping cell voltage lower
First word insists underlining.

keep
verb
1.
have or retain possession of.
2.
continue or cause to continue in a specified condition, position, course, etc.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

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