The Joy of Sorting Cells

Dr. Dickie

Member
Joined
Sep 23, 2020
Messages
74
Sorting Cells.jpg

Okay, I have asked a million questions, and everyone here has been great at helping me understand everything I did wrong.
Since I have no knowledge to contribute, how about something a bit different than "Burning Down the House."
The Joy of Sorting Cells--I should come up with the Zen of this as well.
Here is what I am doing--my process.
The Zip lock bags contain the days processed 18650s (IR, charge, capacity discharge, re-charge, IR). There are 25 of them, for the 25 days they then sit to get tested for self-discharge.
The bins contain the cells after their 25 days of "time out," for self-discharge. They are grouped by 10 mAhrs--although that is certainly below the noise level I get with the Opus. At one point I had a small secondary fan blowing down into the two Opus I use, this reduced the capacity measured by about 50 mAhrs by cooling the cells down. I stopped that so the assessment would be fairly uniform, if not accurate.
I am getting to where some bins are close to overflowing.
How do you sort your cells?
 

LithiumSolar

Administrator
Staff member
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Oct 8, 2016
Messages
2,381
The joys of looking at clean, sorted, tested cells :D

When I built my last round of packs, I didn't do any sorting. I just threw the 3000 cells in a big pile, mixed them up, then moved down the row of 14 holders placing one in each holder. The cells are randomized, as are the distribution to packs in case there were any "pockets" of similarly tested cells.
 

Wolf

Well-known member
Joined
Sep 25, 2018
Messages
1,282
In your case as they are all the same cells (Manufacturer and part number) the throw in a big pile method would work just fine.
They are all 2600mAh LG M26 cells with close IR and capacity results. Now if you had a Frankenstein collection of cells my answer would be different.
Wolf
 

Ebikeforlife

Member
Joined
Jan 6, 2021
Messages
35
My own way of sorting cells is mainly due to having lots of boxes that brand new cells come in as i build ebike batteries, i dont throw these away and save them for my tested cells... each box holds 100 cells and i put them in 100mAh boxes.

So far i have boxes of

2700, 2600, 2500 etc down to 1600mAh boxes

My highest concentration of cells are in 23,22,21,20,19 hundred mAh

i also sort the branded from the generic

I have about another 500 cells to test within this batch of laptop batteries and then decide which way to build.

After some of the posts, i may have to do some retests to double check the IR as not all have been noted.
 

Dr. Dickie

Member
Joined
Sep 23, 2020
Messages
74
In your case as they are all the same cells (Manufacturer and part number) the throw in a big pile method would work just fine.
They are all 2600mAh LG M26 cells with close IR and capacity results. Now if you had a Frankenstein collection of cells my answer would be different.
Wolf
I made a million mistakes even though all the cells are the same. Can you imagine the mess I would be in if I had hundreds of different cells!!!o_O

This was supposed to be my learning project, and I have. That was why I specifically started with as little variation as I could.
And again, thanks Wolf, you have been a huge help.
 

Dr. Dickie

Member
Joined
Sep 23, 2020
Messages
74
The joys of looking at clean, sorted, tested cells :D

When I built my last round of packs, I didn't do any sorting. I just threw the 3000 cells in a big pile, mixed them up, then moved down the row of 14 holders placing one in each holder. The cells are randomized, as are the distribution to packs in case there were any "pockets" of similarly tested cells.
I only have about 100 more cells to process--then a month wait for the final ones to sit for self discharge test. Since I have cells sorted into 10 mAmp capacity (I know that is silly, but it is done); my plan right now is to start with the highest capacity bin (2780 mAhrs), and log the cells into repacker with the lowest IR (34 mOhms),then move to the next bin on down to 2600 mAhrs The start again with the 35 mOhm cells until I get the 2240 needed.
I got 500 more cells than I need, and have dropped about a hundred or so that tested bad and another 100 or so that are below 2600 mAhrs.
Of course since I screwed up in making sure all the cells with less than 2V at the start were marked as such, once I get the packs made, I am going to capacity test them looking for heaters!!
 
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