Quality Samsung cells

mccabian

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Feb 4, 2018
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I am just wanting to get a bit of an idea of the quality of different cells.
Reaching about a few hundred pulled cells now, I am starting to see a trend of dead 0V cells.


image_yvjweb.jpg


Is it just statistically unfortunate, or are you guys seeing the same thing?
On the other side are the red wrapped with thicker heatshrinkSanyo one's which nearly always are proper and pack 2100 mAh+

Looking forward to hearing about your experiences.
 
Normal. It differs from batch to batch
 
daromer said:
Normal. It differs from batch to batch

What do you mean exactly? It happens to you too that the Samsung ones tend to be in the worst state?

All the cells I have now have been pulledfrom old laptop battery's, which came from a whole bunch of different places. But for some reason nearly always the Samsung cells are dead, and definitelynearly all the dead ones are Samsung cells.
Just wondering if there really is a causality here and that Samsung manufactures (manufactured) low quality cells?
 
I pulled about 216 cells from the same type of laptop batteries. They were about 40% sanyo and 60% Samsung. Nearly all the sanyo were bad are very low capacity while a lot of the Samsung batteries were good.
 
Correlation vs. causality ;)

For a start, Samsung cells are very often used in laptop batteries. Much more often than Sony, for example. Even Sony batteries don't always have Sony cells, which was a bit amusing when I found out.

Anyway, when most of your cells are from Samsung then most of your dead cells will be from Samsung as well. When processing roughly 1000 cells I couldn't find any statistical evidence that Samsung cells are more often dead than others.
 
Another thing to note, just because a cell is <1V, doesn't make it bad. It just needs very low mA charging, around 250mA or less. You can achieve this by connecting several in parallel and charging with a standard TP4056 charger as it can only do 1A max. So, 4 in parallel would be 250mA per cell.

once the cell is over 3V, you can then charge it normally.

Now, 0V cells are a different story. Personally I would not even try to revive a 0V cell. As long as you can read voltage, you can charge it. But 0V could mean several things. The CID popped, it's 100% discharged either by self-discharge or just drained that low, or there's an internal short caused by dendrites. All of these reasons would be bad to the cell, and the latter could be detrimental to safety. And never ever reset a CID (unless for curiosities sake and experimentation; but never production). It popped for good reason.
 
Here's my dead cell list. No correlation to brand that I can see, but definitely correlated with age; these were all from very old laptop battery packs. Time spares no one ;)


image_qnvbsd.jpg
 
I've had the opposite experience; Samsung's have been great for me. Bad cells have been pretty random.
 
@darkraven

"Correlation vs. causality"

That was indeed the thing I was looking for with my post to get down real world figures from others. I have processed afew hundred cells and it just seemed suspicious as they were from a bunch of different sources but it would be always the Samsung ones that were dead. Good to see it is no indication of the quality if the brand. Thanks guys!
 
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