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"Generic" Cells - Are they any good?
#31
Just test their capacity and then you could select them for different purposes.
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#32
Geek: One of my motivations for starting this test was the lack of data sheets for these cells. In all of my searching, I couldn't find anything. CJ does have some data sheets for the new versions of their cells, but nothing for the cells I have (2011 - 2014 manufacturing dates).

Sorry for my leave of absence, it says my last login was the 22nd of April. Ouch. Just took a break from this forum and used forum time for other stuff. I did keep this test going. I've now dedicated my Opus to this test for 1/3 of a year now. Wow. Yes, I just finished my 350th cycle! Didn't think I would make it this far, but I'm really glad I did. Here are some results: 





And here is the degradation (second number is Cycles 301-305) as calculated by the method mentioned by Wolf back in April. Makes more sense to do it this way. Assuming I reach 405 cycles, I will use this same formula. 



It seems the more data I gather, the more questions I have. Like, why am I seeing such small degradation? Is there something wrong with my Opus? With my testing method? For example, the data sheet for the LG cell rates the cell as 80%+ remaining capacity after 300 cycles. The LG cell that I'm using in this test came from a used Laptop pack that had an unknown number of cycles and cycle equivalents. And yet, 350 cycles after an unknown number of previous cycles and like 8 years after the cell was manufactured, the LG cell is still doing great! Oh and the generic cells are not doing bad either. I mean the THLD cell has seen 6% degradation, and Cycles 348-350 were the first times this cell saw less than 2000mAh, but this is like a generic cell that nobody has heard of, unlike a number of people who have CJ or ASO cells. I was expecting 100 cycles before this cell was toast and it's nothing like that. Does anyone know what's going on here?
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#33
Thank you for keeping this test going and reporting back here.
There is never very much real information of this type because it takes so much time and effort.
It is great to see real life degradation info.
I think this gives second life storage members hope (and reason to think) that thier cells can last well.
Thank you again.
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#34
(06-04-2019, 03:49 AM)Dallski Wrote: ..............I mean the THLD cell has seen 6% degradation, and Cycles 348-350 were the first times this cell saw less than 2000mAh, but this is like a generic cell that nobody has heard of, unlike a number of people who have CJ or ASO cells. I was expecting 100 cycles before this cell was toast and it's nothing like that. Does anyone know what's going on here?..............

Great test. That took some dedication.

The only thing I can think of is that there are some "cell manufacturers" (how many plant that make 18650s really are there?) that buy class "B" cells from major manufactures. As in slight cosmetic damage like the print on the wrapper was wrong or it didn't get printed. The wrapper was not shrunk right etc etc.
I mean when you manufacture millions of cells in a high speed environment there is bound to be something that goes wrong on a regular basis.
So to recoup some cost these cells are offered to the aftermarket.
So I'm thinking they buy these cells pennies on the dollar rewrap and sell at a reasonable profit. In essence you are getting a properly manufactured cell with a generic wrap. I'm just guessing of course. But  it certainly sounds entrepreneurial for some industrious chinese fellow.

Wolf
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 75mΩ or less Smile
Last count as of 6/10/2019
Total Number of Cells                          5940
Cells  >80% of Capacity                      4334
Cells <80% of Capacity                       1605
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2800 +236
For Info Google Drive
Not your average Wolf       
            Cool



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#35
Thanks Oz! I agree! I see a lot of theory and data sheets, but I really haven't seen anyone take the time and effort into actually testing any cells. I guess most forum members should pay attention to how the LG cell does, as most people discard the generics. As for real life, I think the results would be even better, but I'm kind of stress testing these cells to compress the time. There's no way in real life would you do 3 full charges and discharges just about every day at 0.5C and leave cells fully charged every night.

Wolf, that's what I believed at first, but I'm pretty sure these are all non-Japanese and non-Korean cells. These are all probably produced by factories in China, Thailand, Singapore, etc. I have generic cells from 40 different manufacturers and counting. One thing I have noticed is the positive cap. You can usually identify a Japanese or Korean cell from the positive cap depending on if it has 3, 4, 5, or 6 prongs because each manufacturer has its own patent on its number of prongs. I think there are a few main generic manufacturers like CJ and ASO, and then there are more generic generics that rebrand those cells as well, based on similarities to the positive caps.

I know we all think of China as crap and inferior, but you have to remember that these are the same people that are capable of making high quality items like iPhones and stuff. And China blatantly rips off intellectual property from around the world. So it's very possible that you can have an 18650 manufacturer in Shenzen making Samsung copies that are actually good. Just throwing that out there.
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#36
Brilliant work Dallski ... this fills in a big gap in our knowledge .... just what sort of life can we expect from generic cells ???

It would seem from your early results that they hold up well , perhaps just as good as recognized brands ... this sounds logical , it's basically the same chemistry...

It's like all things , people don't know what to trust , and so are prepared to pay more for sony for some sort of piece of mind , but it appears there's no need  ....

What we want now is to decide on a good supplier ... there's a guy on Youtube who buys from 'Queens'  , he does a very professional job of testing capacity ... some cells from Queens , slightly larger than 18650 , sell for 6.5 WHrs/$ including delivery , the best value I've seen.

This is the channel and cell ... https://youtu.be/4jiL9sKleEg
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#37
Hi Ozz, there is more to a cell than just cycle life. I will also be testing for safety in the near future, like seeing if the generics skimp on PTC and CID protection. Seeing the generics perform well is like you mentioned, it's just chemistry. Unlike Lead Acid, most of the cost of lithium ion cells is not the raw materials, but rather the processing of those materials as well as R&D, and assembly. Generic cells are cheaper than brand name cells mostly because the Chinese manufacturers steal all the IP from the big names. It's very similar to why generic drugs are usually so much cheaper than the name brand drugs. And I would break down generics further into (1) name brand generics like the three I'm testing; (2) generic generics like the ones that just say "INR18650 3.7V" or something similar; and junk generics like Ultrafire (rewrapped end-of-life genuine cells) and Trustfire (new cells with 1000mAh or less capacity). You do get peace of mind from buying brand name cells, though. I wouldn't be doing this testing if I knew I had legit Samsung or LG cells.

Also, the video you refer to - that's Thunderheart, a well known member of this forum. You can see his posts here, he is very thorough in his research. He buys from Queen Battery, check his videos for a link.
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