Old salvaged Panasonic NCR18650 still performing like new!

i just got 4 samples from a local battery "recycler". these are Panasonic NCR18650. the OG NCR 2900mah w/ old-style gray wrapper (dotted)

iCharger 2.9A discharge (1C) down to 2.5v

one did 2933mah! the others aren't far behind

what's going on? they're supposed to be performing much worse! even if they weren't cycled the calendar degradation should've gotten them...

...And,.. Most manufacturer discharge tests are done at only 0.2C for capacity verification. !

i know right! these cells are really ageing well. btw panasonic NCR is NCA chemistry, while CGR is NMC

NCA has been touted to have superior calendar life. these cells definitely prove it

i've got NMC Samsung 26F that have deteriorated quite a bit by just sitting there idle

Check the internal resistance. That goes faster than capacity. But otherwise, lucky you. They may have sat mostly discharged in a dark cool place for most of their life.

I've tested 9-10 year old Sanyo 2400mAh cells that tested like new (2370-2380mAh+ capacity) and new AC IR of 50 mili ohms. They were pulled from new old stock Fujitsu packs.

iCharger 106B+ internal resistance tests (fully charged). i know i know, not the best method but consistent enough when using my cell holder (w/ the soldered leads)

NCR gray Cell1: 79
NCR gray Cell2: 83
NCR gray Cell3: 76
NCR gray Cell4: 76

NCR-GA (used): 64
VTC5 (quite old): 46
LG F1L (new): 69
Samsung 26FM (used): 112


i think i'll buy more and build a 13s4p out of them. you think they'll give me 4 more years of service?