No doubt you say that based on randomized, large scale, longitudinal studieslorenfb said: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 studieslorenfb said:Of greater concern should be excessive battery temperature the result of ambient, charging current (QC), and motor current while driving.
Oils4AsphaultOnly said: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.
SageBrush said:No doubt you say that based on randomized, large scale, longitudinal studieslorenfb said:Of greater concern should be excessive battery temperature the result of ambient, charging current (QC), and motor current while driving.
lorenfb said:Oils4AsphaultOnly said: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.
lorenfb said:SageBrush said:No doubt you say that based on randomized, large scale, longitudinal studieslorenfb said:Of greater concern should be excessive battery temperature the result of ambient, charging current (QC), and motor current while driving.
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.
arnis said: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.
Oils4AsphaultOnly said:[
A good engineer extrapolates off of the conclusions of those studies to draw reasonable conclusions in the absence of supporting evidence.
lorenfb said:Oils4AsphaultOnly said:[
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%?
lorenfb said:Again, the time factor in the various states is being ignored, and that's NOT scientific!
First word insists underlining.keeping cell voltage lower
You are playing word games.arnis said: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.
The evidence for charging habits is a lot more murky but Nissan doesn't think that charging to 100% should be a problem and all Leaf's do just that by default. Leafs in Europe and Japan don't seem to have problems due to charging to 100%
... Let me amend your sentence to:johnlocke said:The evidence for charging habits is a lot more murky but Nissan doesn't think that charging to 100% should be a problem
How many people actually use the 80% option if it's still available in Europe or Japan? If it's used by most people over there, then I'd amend my opinion. If most don't use that option, I'd still suggest that charging isn't a major problem because their failure rates are much lower. We don't see this problem in the northern half of the U.S. either. If charging to 100% was a major factor, I'd expect the failures to be better distributed across the U.S. I'm not saying that it has no effect, just that it's probably minor compared to other effects. Nissan claims very low failure rates for the battery overall and I have no reason to believe they would lie about that. There is a cost analysis by Nissan here that says that failure rates overall are low enough that it's cheaper to replace failed batteries than re-engineer the battery. Also that the level of battery failures won't affect sales enough to be a problem.SageBrush said:... Let me amend your sentence to:johnlocke said:The evidence for charging habits is a lot more murky but Nissan doesn't think that charging to 100% should be a problem
[should not be a problem] for Nissan, meaning the battery should make it to the warranty end.
How reassuring. NOT
johnlocke said:I'd check with GaryGID to say for sure but I've never seen a report of more than 363 GID's on a new car even when the owners reported AH values over 82 AH from Leaf Spy. I think the value is software limited by the BMS. That would explain why some cars report the same value (363) for months before the the GID's value starts to drop.Oils4AsphaultOnly said:ironmanco said:I noticed in your sig that you only reference GID as a representative of the condition of the battery. Is it always a 1:1 relationship of the SOH of the battery and the GIDs?
I think so. And I think 380 GIDs was 100%? I don't have a concrete number since I didn't get the leafspy stats on day one. I did think it was rather odd that SOH was showing 100% all way to 7000 miles (~4.5 months of winter-spring driving)! So for me, I trust the GID number more, since it's a more detailed number than X %
DaveinOlyWA said:I am fully confident I can pop it back up to 100%
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