Green Sony cells just suck

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jm1

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Dec 14, 2017
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So Ive tested probably 1000 18650 cells so far from laptop packs and noticed a disturbing trend in the green Sony cells. Most test pretty decently on the initial discharge cycle test (between 1900-2200) but on every single capacity test after that they steadily lose 100-200 mAh per test so I would imagine it would be impossible to balance a pack with these. This is not a case of inacurate Opus with value jumping up and down by 100 mAh or so, this is a clear trend in the downward direction by 100+mAhon every cycle.

I now recycle all these cells and if I start opening a pack and see green Sony I juststop wasting my time on that pack. A little disappointing as well because I had a lot of these in my "good" pile before I noticed the issue with them.

Do any of you notice this same trend?

I cant imagine Im the only one because the packs were from different manufactures and different years but all the same result.
 

Korishan

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Good point. Thanks for bringing it up so we can keep an eye out for them. Can you go over to the Cell Database and make a note on those too? That way others will see it when looking up data on the cells
 

Geek

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How many cycles did you do? It would be interesting to see if there were an end to this loss. What revision opus? Could it be that these cells do not like going down to 2.8v
 

jm1

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Geek said:
How many cycles did you do? It would be interesting to see if there were an end to this loss. What revision opus? Could it be that these cells do not like going down to 2.8v

You make some good points.Ive only done a maximum of 4 cycles because I only have 4 Opus chargers and I want to keep moving on processing cells plus by this point they are already below capacities I am interested in. My Opusesare allversion 2.2.


Korishan said:
Good point. Thanks for bringing it up so we can keep an eye out for them. Can you go over to the Cell Database and make a note on those too? That way others will see it when looking up data on the cells

I will certainly do this.
 

The-J-Man

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mike said:
You mean you're actually able to test yours? 90% of the cells I've been harvesting, even from new old-stock packs, have 0V so I can't even test them.

damn thats unlucky, ive had maybe 3 packs below 0.05V :D
 

jm1

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mike said:
You mean you're actually able to test yours? 90% of the cells I've been harvesting, even from new old-stock packs, have 0V so I can't even test them.

Yeah and most looked awesome on the initial cycle. After I figured out what was happening I had to go back and pull a hundred or so out of my good pile, pretty disappointing.
 

Daveyboy

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Aug 6, 2017
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Damn. I will have to pull all my Sony's out before I start welding my packs up. Thanks for the headsup!
 

DCkiwi

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jm1 said:
[...]
Do any of you notice this same trend?

not me. this 10s12p pack is 100% sony from used laptop batts. bad luck mate.


image_fsgftb.jpg


and they're all 'triple tested' for capacity.


image_jjdluq.jpg
 

Wolf

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I've only had experience with the "green" SonyUS18650 G5 and G6 and a couple of G8 and so far have not noticed a reduction in mAh capacity on cells with an IR of 70mΩ or below on subsequent charge and discharge cycles.

image_gvelir.jpg


The G5 I only have 33 cells in the database but it looks as if the IR cutoff is around 78mΩ for at least 80% capacity.

image_mfdtak.jpg


The G6 I would definitely make 70mΩ my cut off although there are some stragglers at >80mΩ just hanging on I will re-test those in the future.
An occasional dip in the acceptable range but that's to be anticipated.

image_ordmsa.jpg



Wolf
 
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BlueSwordM

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@jm1, at what voltage are you recovering the cells, and at what current level?
 

DCkiwi

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BlueSwordM said:
@jm1, at what voltage are you recovering the cells, and at what current level?

I'd also like to know with what hardware you are [pre-]charging them .. better not be an Opus ... *ugh* ... (they pulse charge at INSANE high current -- do NOT use as chargers!).
 

jm1

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DCkiwi said:
BlueSwordM said:
@jm1, at what voltage are you recovering the cells, and at what current level?

I'd also like to know with what hardware you are [pre-]charging them .. better not be an Opus ... *ugh* ... (they pulse charge at INSANE high current -- do NOT use as chargers!).

So are you stating that the Opus would damage or kill the Sony cell but not degrade the LG's and Samsungs for example?

I have a few different hobby chargers and I can set the voltage and amps to the exact level I want. I also have an Opus farm so I use those to charge when I have more cells then places to charge them.

I gone through about 1800 cells from various battery pack manufactures and various yearsall the green Sony cells exhibit the same characteristics. They look great on the initial cycle and then drop considerably on every cycle after that.

I don't recover any cells that start off lower then 2V, if I open a pack and its <2V I put them right into the recycling bin. I just took 100's of green Sonys that tested above 2000 to the recyclers and I no longer process them since the pattern is the same. I have enough of the better more stable name brand cells that I don't have to waste the time with the questionable ones.

If people think these work then I will have a bunch of green sony packs (not processed) that I will sell for barely more than the price of shipping.

I would have to add: I see in another thread you use very low mA charge rates off less than 500 mA. Once my cells are into the standard voltage range as specified by the manufacturer, I charge and discharge at nothing less than 1A because thats how I intend to use my packs in the real world so if they fail at 1A they are not suitable for my project.
 

BlueSwordM

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@jm1, when below 2,5V, I start a process called low current low voltage recovery.

It's basically to lower damage to the cell as low as possible during recovery.

Charging at 1A, depending on how long the cell had stayed below 2,5V, can cause capacity degradation after a few cycles.

The Sony cells may have stayed a long time below 2,5V compared to your other cells.

Therefore, there is a possibility that when you recovered them at 1A, there was physical degradation during the initial charging process which reared its ugly head after some time.
 

jm1

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BlueSwordM said:
@jm1, when below 2,5V, I start a process called low current low voltage recovery.

It's basically to lower damage to the cell as low as possible during recovery.

Charging at 1A, depending on how long the cell had stayed below 2,5V, can cause capacity degradation after a few cycles.

The Sony cells may have stayed a long time below 2,5V compared to your other cells.

Therefore, there is a possibility that when you recovered them at 1A, there was physical degradation during the initial charging process which reared its ugly head after some time.

I agree could be my method causing the issue.I have 100's of pounds of packs so I dont want to be doingmultiple gentlecycles on the cells otherwise I would be at this for about 5 years, lol. I dont normally ramp up to 1A of charge until the cells show a voltage of 2.8V or higher. For now Im putting all my red Sanyoand green Sony packs a side and If I get desperate at the end I will process them. At least most packs have just a sticker over the battery section of the pack so its nice and easy to take a quick peak before I waste time opening the pack.

As it is by the time I finish this project the standard battery chemistry out in the world will be much more advanced.
 

Wolf

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I'm going to go break some cells apart and hope to find some 'green" Sony cells.
Will measure V and IR fresh out of the pack.Charge some at 500mA and then run them through a barrage of capacity tests recording every measurement along the way. Slow charge some at 50mA and do the same.
Let see what the results are in a week or so.
Documentation is what proves the conversation. Without documentation it's all just hearsay.

Wolf
 

jm1

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Wolf said:
I'm going to go break some cells apart and hope to find some 'green" Sony cells.
Will measure V and IR fresh out of the pack.Charge some at 500mA and then run them through a barrage of capacity tests recording every measurement along the way. Slow charge some at 50mA and do the same.
Let see what the results are in a week or so.
Documentation is what proves the conversation. Without documentation it's all just hearsay.

Wolf

I look forward to your results.
I still have about 50 green Sonys left in a pile that I wrote 2000> mAh values on all of them after an initial cycle more than 1 year ago. I've processed enough now that I know with 100% certainty if I run those through the same test now all the capacitieswill be lower by 100+ mAhand will continue to drop significantly with each test cycle. This never, everhappens with any of my LG or Samsung cells.
 

BlueSwordM

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@Wolf, I think I should have recorded the data too. It would've made for a great post actually.
 

DCkiwi

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jm1 said:
DCkiwi said:
I'd also like to know with what hardware you are [pre-]charging them .. better not be an Opus ... *ugh* ... (they pulse charge at INSANE high current -- do NOT use as chargers!).

So are you stating that the Opus would damage or kill the Sony cell but not degrade the LG's and Samsungs for example?

I have a few different hobby chargers and I can set the voltage and amps to the exact level I want. I also have an Opus farm so I use those to charge when I have more cells then places to charge them.

An Opus 'charger' may damage any cell ... will it? not entirely sure.

But I AM sure that an Opus can't be turned right down to 100mA like a hobby charger. (which I then split four ways in the 6s4p yoke)

I pre/charge so slow and so many cells .... it works out to be roughly an 8-10 to 1 ratio of charging slots I have to have, to testing slots. things got much easier once I added a 6s12p yoke to my 6s4p ones. (pictures coming today in another thread, will link from here). there is simply no way my Opus's could come close to coping with volume of charge I do.

and yeah, it would totally WRECK all the <0.5V recovered cells. they would all end up testing great once, then rapidly losing all capacity. sound familiar?


jm1 said:
BlueSwordM said:
@jm1, at what voltage are you recovering the cells, and at what current level?

I don't recover any cells that start off lower then 2V, if I open a pack and its <2V I put them right into the recycling bin. I just took 100's of green Sonys that tested above 2000 to the recyclers and I no longer process them since the pattern is the same. I have enough of the better more stable name brand cells that I don't have to waste the time with the questionable ones.

If people think these work then I will have a bunch of green sony packs (not processed) that I will sell for barely more than the price of shipping.

I would have to add: I see in another thread you use very low mA charge rates off less than 500 mA. Once my cells are into the standard voltage range as specified by the manufacturer, I charge and discharge at nothing less than 1A because thats how I intend to use my packs in the real world so if they fail at 1A they are not suitable for my project.

anything under 3.3V is pretty damaged, IMHO. I dont see ANYTHING special about your 2V cutoff point.

this damage can be remedied. it needs a SLOW precharge, VERY LOW mA charge rates. 20-50mA per cell is lots. and let them 'breathe' after a few hours too. give them an hour or three break before resuming slow charge. you are rebuilding the internal chemistry at this stage, and it simply cant be rushed (AFAIK).

I understand your desire to test them at full speed. However, recovering cells from this low a voltage is going to take a full cycle (or three!) to settle back into productive life. I used to do same as you ... and now regret killing and disposing of so many 'heaters' or 'failures' as I thought. Nowadays I still get failures, but not for this reason.

Your method of putting these 'high maintenance' cells aside until you run out of easier cells to process is a winner, I reckon.
 

Wolf

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So,
Because I like you guys I went out into the cold of winter and mulled in my head where would I find "green" Sony cells.
HP probably not, Dell na, Aha Lenovo should have some. So I dug through my pile and found all the lenovo bats. I could find. This is about a third.

image_okuykd.jpg

So I started tearing apart the packs and at first was disappointed to only find SANYO UR18650FMs. But as luck would have it,here is the first Pack.

image_meeksh.jpg

Then they just kept on coming,

image_eqwexe.jpg
:D

I also scored a bunch of others. Lots of the Sanyos 18650FMs and some others.

image_vszxpx.jpg


Here they are all separated and in the box to be brought in for their final delousing and cleaning.

image_ttnqnz.jpg




They are SONY US18650GR G8

image_yqwqiv.jpg


And here they are ready to be tested all cleaned up and happy (well we will see about the happy part)

image_rqmldn.jpg

I will create a seperate sheet for these in Excel and record everything from start to finish.

Wolf
 
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