The cells I bought were represented as being unused, new old stock, grade A, 280 AH cells.
Which reseller?
Some say new old stock, "grade A",
Some swear they are new 2020 cells and "grade A",
A couple have been upfront from the beginning and stated they are not grade A but not coincidentally nobody opted to buy from them.
Personally I believe they are all selling the same cells and most are being dishonest about cell grade.
At the end of the day, they all may be partially right, some may be misinformed or misrepresenting the truth. We can't fully know. This is why I think the term grey market is very fitting there is very little transparency and a lot of misinformation.
The cells I received did not look used.
You may misunderstand the terminology (or maybe you are just responding to the specific part of the quoted text that referenced possible used cells). A/B/C grade is a totally separate from new/used, all these cell grades apply to new cells.
The terminals are not scratched, there are no dents and the QR codes are legible and have not been defaced. I would expect cells that have been sitting on the shelf for 3 year to have lost some capacity.
Exactly, which is why manufactures will downgrade the rating after some period of time. This--along with cells that come up a little short on capacity from the factory-- (in my eyes) would be the absolute best type of B grade (or "A-" depending on the manufacturer and level of fade) cell to get (ones that just age out of their new A grade status but were otherwise good and healthy cells). But this is just one of a half dozen or more possible reasons, not all of which are readily observable. If you look at the variability among cells received I think it supports the idea that the cells we buy from resellers are a mish-mash of cells discounted for various reasons.
If I get 255AH capacity or better then I am going to be ecstatic. If I get better than 240AH I will grumble a bit but accept them. If I get less than 240AH, then I am going to be talking to my vendor, since this indicates to me that these cells were either not stored properly or else these cells were in fact rejected (Grade B) cells when they were made.
My understanding is the capacity threshold between A grade and non-A-grade (for an EVE cell) is
>280 vs
<280, (of course, with our limited means to test, measurement error is quite possible so it makes sense to be more forgiving, especially for a single test).
Research shows that capacity loss of approximately 12% would be typical for cells stored at reasonable SOC and temperature.
View attachment 34062
Those charts appear to show extremely high (to the point of negligence on the part of the seller) storage temperatures. But I get your point (and agree) some capacity fade over time just from sitting in a warehouse is normal and to be expected with old cells.
Anyways, I didn't mean to contribute to pulling this thread off topic, sorry
@Bob B
@HaldorEE if you want to discuss more lets continue in PM or we can just move along