Samsung SDI 35E - 3 diff batches, is it safe to say that they are all a 35E?

[AFAN]

Samsung SDI 35E - 3 suppliers - 1 legit, 2 fake?​

Hello, Can anybody help asses if these 3 samples of Samsung SDI 18650 35E cells are the real thing, i suppose the first one is [the oldest one form a coouple of years ago], but recently 2 more samples from different suppliers were aquired, tested for capacity and mR on a simple tester the oldest one ~3200mah and 20-40IR [basic pulse tester, probably not precise][been cycled maybe 20 times through those years] and the other two score about ~2700-2900mah and 20-40IR, times of discharge and charge are similar and no thermal camera to check the temps, they were charged/discharged @ 1A
i could only decode the oldest one and the new ones coding seems far away from what the internet describes as legit samsung sdi batch code,
thank you for leaning on this ; )
oh and the + on the third one got bigger..

 

[AFAN]

Hello Boys and Girls, providing a couple of fresh photos for reassesment, took the thermal plastic off, please feel free to discuss any of this

 

[AFAN]

newest update - didnt see them before - labels on the negative terminal: Z3 , Z6 , and on the most suspicious cell - nothing, if you look closely the OLD BATCH and NEW BATCH#1 are almost identically made, you can see the metal changing tone in certain areas, so i guess the 1 and 2 are indeed 35E and the last one isnt, cheers

 

[bombastinator]

@Mooch knows how to do that. It’s quite involved iirc you charge the thing up full and graph the discharge rates and levels then compare it against known samples. Markings were getting unreliable 10 years ago.

 

[Axxe]

Just something I noticed: No. 3 is also lacking the "series" marking. There's usually a number (well known i.e. for the Samsung 25R with the famous "series" 25R5), for No. 1 and No. 2 it is "3", but on No. 3 there is nothing there.
Edit: Just looked at the photos from HKJ's page and his earliest test of a 35E shows a cell without "series" marking, too. The same is true for Mooch's first test.

Don't know if Samsung changed something about that, but I found it to be interesting when looking at your photos. My hunch would be that at least No. 3 isn't authentic, but that's just my gut feeling from the info and photos you posted (especially the lower weight). I guess Mooch would be the most competent person to answer this than anyone else.

 

[bombastinator]

I just buy from know good online retailers and hope.

 

[Mooch]

newest update - didnt see them before - labels on the negative terminal: Z3 , Z6 , and on the most suspicious cell - nothing, if you look closely the OLD BATCH and NEW BATCH#1 are almost identically made, you can see the metal changing tone in certain areas, so i guess the 1 and 2 are indeed 35E and the last one isnt, cheers

IMO cell #3 isn’t a 35E but I can!t say for sure about the other two without testing.

 

[AFAN]

gathered some new data, didn't know before that it would suffice,
[wanted to do some more testing at 5A,10A with a real world setup [not sure of the little pcb tester],
multiple points on discharge curve @ 1A concur with Mooches assesment:

#1 #2 - good product
#3 - discharge curve @ 1A starts to deviate down in ranges 3.5V [Vdrop starts] - 3.0V [V stabilizes and till the end of the test stays in the same region]

in other words somewhere at the 2000mAh marker the X099 batch starts suddenly to drop voltage and it goes to 2900mAh, stabilizes @ 3V and stays like this till it hits the end at 3108mAh,

#1, #2 curves respectively align with the data showed on lygtes chart @ 1A, #1 stops at 3244mAh, #2 at 3338mAh

anyways im going to do the high discharge tests with a temp probe just to try and figure out what is the actual X099 chemistry/model and to check its safety in a theoretical Ebike pack project