DougWantsALeaf wrote: ↑
Thu Feb 20, 2020 4:47 pm
Do we have any reason to believe that the SOH isn’t accurate or a good relative measure any more?
I think he is referring to Hx as not being reliable or a good metric to go by.
SOH and ahr seem to align rather well as the pack ages.
I have been gathering (trying to anyway) gather data about Hx issue since Feb 2018 where its randomness achieved a whole new level of weird but even when specifying parameters, 80-90% of responses were all but unusable so not a lot of decent data out there.
As far as Hx; It would appear that for most, it starts out very high during the period when loss is greatest. That is the most common characteristic. There is "some" evidence that higher use of DC sees the higher numbers exceeding 120%. With NCTC all but gone for the Plusses, might have more light on that in 6-12 months.
After that; its mostly two groups, maybe 3. As the degradation slows going into month 12-18, the Hx starts dropping hovering around 100%
Then we have a group that has continued degradation that is only "medium better" than the initial drop and has Hx below 100.
Problem with all this is huge gaps in data gathering. Some people only check their stats 2-3 times a year OR LESS.
The other big issue is people injecting their own opinions into what is important and submitting only that info w/o understanding that data gathering is "supposed" to be unbiased. We are only crunching numbers, not evaluating charging habits.
Come Summer, will be doing another round of data gathering... Hopefully with better results.
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 4411.3 mi, 96.88% SOH
My Blog; http://daveinolywa.blogspot.com
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