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Processing Low V Cells
#11
(06-04-2019, 10:37 PM)Dallski Wrote: Wolf, you are probably right. If I had more used cells, I probably would invest in a proper IR tester. It all comes back to IR, with a few exceptions as you have found.


 I have just had a lot of bad luck with <1V cells and I think it's because I was just throwing them in the TP4056 and charging them at 1A after they got to 2.92V. I lost a lot of cells that tested well initially. But then again, they could have been high IR cells to begin with, so who knows?

@Dallski

What do you mean probably right? You now I'm right, probably. Tongue

Anyway I did the same thing as you initially. I just threw the cells into the TP4056 board that I built and called it good. Then the sadness came when the cells had no mAhs in them. The bad bucket was growing faster than the good bucket. It was just such a waste of time to charge these cells even with good voltage and have such a low return. There had to be a better way. There is of course and we all know what it is.

So my first giveaway was ~1000 cells that I tested and and found to be lacking.


My second giveaway consists of ~3000 cells maybe more. Another ~1000 or so cells cells that I tested and found lacking but the rest of the ~2000 cells never made it to the chargers the IR was to high. So I saved myself countless hours of testing cells just to be dissapointed.
   

Now that I have my 2800 + cells I can concentrate a little more on experimenting with cell charging methods and so forth.

Amazing how fast you can accumulate good cells when you place 44 cells into your chargers and pull out at least 42 to 43 good cells if not 44 at a time. Big Grin

Wolf
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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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#12
(06-05-2019, 01:01 AM)Wolf Wrote: - snip -
Amazing how fast you can accumulate good cells when you place 44 cells into your chargers and pull out at least 42 to 43 good cells if not 44 at a time. Big Grin

Wolf

In effect you have made my pipedream come true. Exactly true. Not only true, you PROVED it.
Chapeau !

And now i do want to know, why do i have a 100 % successrate on reviving 180 low-U cells?

And others have not ?

I will sacrifice the next low-U block i get to a binary parameter check. Half of the cells with a minimal current, the other half with a binary increase.
Any other ideas or wishes ?
1 kWp in Test
4 kWh battery target - plus Mobile Home battery
Ultra low cost
Electronics ? No clue. Am machinery engineer.
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#13
(06-05-2019, 06:47 PM)Cherry67 Wrote: In effect you have made my pipedream come true. Exactly true. Not only true, you PROVED it.
Chapeau !
You are welcome and thank you
Ah yes it only took 1500+ cells to slowly come to the conclusion how relevant IR is to a successful harvesting strategy.
Not only does it virtually eliminate heaters, SDs and low performing cells, you will be confident that your powerwall cells will have a reasonable balance with IR and acceptable SOH cells. 
As of now anybody that does not believe in the results is just a denier of the facts and just wants to spend more time testing cells that wont do anything but frustrate.

Quote:And now i do want to know, why do i have a 100 % success rate on reviving 180 low-U cells? 
And others have not ?

IR my friend IR. If the cell has an acceptable IR it is a great candidate for recovery.
One thing you cannot do though is take a ~1V cell and stuff it into a TP4056 and expect it to survive good IR or not.
Now that I have my allotment of cells I will join you in experimenting with very low V cells. Just because I am just as curious as you.
I have recovered cells as low as .0852V that after a CC/CV 4.18 @ 50mA charge was at a 100% SOH as it went through 3 normal 500mAh CDC cycles and had absolutely no degradation. I still have to give them the "30"day sit test to see if they will SD but all indications are good that they will not.
At present I have some cells again <2V and some <1V charging at 4.2 and this time 25mA each it will probably take 4 to 5 days for them to reach 4.18V  then we will see. But again the IR is acceptable on these cells so I expect them to be fine.

Quote:I will sacrifice the next low-U block i get to a binary parameter check. Half of the cells with a minimal current, the other half with a binary increase.
Any other ideas or wishes ?

Poor cells to take such an abuse but its all in the name of the harvest Big Grin

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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#14
Wolf, you have a lot of experience with IR.

From your observations, is it possible for IR to become better after you do recovery attempts on the cells ?
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#15
(06-06-2019, 07:21 AM)Overmind Wrote: From your observations, is it possible for IR to become better after you do recovery attempts on the cells ?

Yes I have noticed that on occasion. Mostly with Sony and some models of LG cells.
I have had IR changes as high as -70% after charging and testing.
Now mind you with my harvesting strategy now these cells would never make it into the testing stage. The IR is too high.
I would not have these cells in my packs as they are sure to cause trouble even though they show a good result.

I would absolutely not use theses cells. 

Now these cells are in the -15% to -11%.
 
Some of these cells I would use as long as the Voltage is OK after the 30+day test and the IR is ≤75mΩ
The Sony GR G* series will not be used at all no matter how good they recover. I find that their IR swings wildly between charge and discharge.
One of my projects is to build a single cell arduino based charger/tester with 1kHz AC IR monitoring during all the stages of recovery to find out what is actually going on there.

The cells that I have documented with a yellow font on the Voltage pretest are the ones that have been recovered from <2V but they are just now coming up on the 30 day retest and I am a little bit behind on that as I am doing April cells right now.

Also the IR was already acceptable and if the IR is on the margin it is indicated by the red font on the IR pretest.


OK enough screen shots you can always check the Excel file out on your own and sort by whatever criteria you so desire. With a cell count of 5855 and constantly growing there is a lot of information there.

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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#16
What is your process for testing IR? I’ve read that the Opus tends to be quite off with its IR numbers.

Since I’m just at the beginning of my cell harvesting, I was thinking it be good to set a start out trying to collect it rather than going back and doing it later.
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#17
(07-06-2019, 08:14 PM)krobertson Wrote: What is your process for testing IR? I’ve read that the Opus tends to be quite off with its IR numbers.

I use a YR1030. It is a 4wire kelvin 1kHz AC IR tester.
You can get it here https://www.aliexpress.com/item/32817594...4c4dqsxf2D
This is the best one I found. But you can get any one of different brands as long as they say YR1030.

All comercial Charger/Discharger/Testers are very poor on IR as they only do DC IR instead of AC IR.  (AC IR  is what the manufactures spec sheets show when available.) Also the contacts cause a varying measurement on a consistent basis so they cannot be trusted.

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



Reply
#18
(07-06-2019, 11:12 PM)Wolf Wrote:
(07-06-2019, 08:14 PM)krobertson Wrote: What is your process for testing IR? I’ve read that the Opus tends to be quite off with its IR numbers.

I use a YR1030. It is a 4wire kelvin 1kHz AC IR tester.
You can get it here https://www.aliexpress.com/item/32817594...4c4dqsxf2D
This is the best one I found. But you can get any one of different brands as long as they say YR1030.

All comercial Charger/Discharger/Testers are very poor on IR as they only do DC IR instead of AC IR.  (AC IR  is what the manufactures spec sheets show when available.) Also the contacts cause a varying measurement on a consistent basis so they cannot be trusted.

Wolf

Are there any versions of these testers that can connect to a network either through WiFi or Ethernet or have USB PC connection?
Then you could barcode and read the cell for a more automated entry.
I have looked and not found the information.
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#19
(07-07-2019, 01:11 PM)Bubba Wrote: Are there any versions of these testers that can connect to a network either through WiFi or Ethernet or have USB PC connection?
Then you could barcode and read the cell for a more automated entry.
I have looked and not found the information.

I bought this Unit https://www.aliexpress.com/snapshot/0.ht...2982590554
and it has a serial communication protocol setting screen
 
so I questioned the seller about it and here was the response.

I guess they are working on it but when it will function.....No Idea.

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



Reply
#20
I was looking into the AI features Microsoft is building into Office.
Here are my plans.

1. Have a unique number on the charger/tester read.
2. Have a it read the number on the slot. (if slot is indicating complete... if not don't get values)
3. Have it read the value directly from the screen
4. Read the Cell number
5. Directly enter it into my database... with minimal interaction.

Currently Microsoft is only released for Cellphones. Waiting for PC use.

Of coarse I could be dreaming..... What do you think?
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