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Green Sony cells just suck
#31
+1 to DCkiwi

Trying to get lots of used cells is really hard, especially ones that aren't at decent voltages.

Especially power tool cells. These are often the best cells for powerwalls, since their internal resistance is quite low even when used, and their capacities are decent.
The problem is that they often end up below 2,0V since the BMS turns off the ability to charge the cells below 2,5-3,0V, but still get drained by the BMS.

I've lost tens of cells just because they exhibited physical damage in the form of large capacity and high internal resistance.
Therefore, as said before, no matter the cell voltage, except for 0V CID, I will try to recover it.
The power of lithium ion is in our hands!
We'll show them what we're made of!
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#32
(01-28-2019, 12:14 AM)DCkiwi Wrote:
(01-28-2019, 12:03 AM)jm1 Wrote: lol, and that my friend is why the green sony's dont work for me!  I use cells at 1A charge and discharge, if they cant do that then they are not suitable for my use.  So its very possible since I treated the green sony's as all my other 1000's of cells, at 1A, is the reason they dont work for me.

mmmmm, maybe.  I get INSANELY old batteries to scrape here.  EG not unusual to get one with a pot-it note stuck to it with a name and 'broken' written on it with a date ... of 2013.  Im not kidding!  so there might be another reason if your cells are fresher than mine ...

have you checked out the forums excellent Cell Database?  it is simply amazing.  best on the planet, i reckon.

apart from older cells being not very super ... the whole recovery from low V thing is a HUGE issue ... I liken it to a giant iceberg ... and all of us on the titanic just hoping it isnt that big under the waterline ... heh.  it sure cost me hundreds of cells ... and that was the pleasant part ---> the worst is all the cells I found later that I thought were great, but now werent.  so lucky they werent all soldered in packs.  that would have ... been stressful!
Many of the packs I get are much older than 2013.  Lots from 2010, some from 2007 etc.  I was actually lurking on this forum and  for about a year before I joined in 2017.  I use the cell database resource and its very handy.  Some of my favourite cells I recover from laptops are the LGDB118650 cells, they can handle a max charge rate of 2.5A and dischare of 5.1A so at 1A Im not even close to stressing them.  Actually all recovered cells perform great for me with only the exception of the green sony's and red sanyo's.  I guess they are not designed for higher current as you mentioned.  I will have approximately 100-200 of those packs for sale soon because even though they dont work for me, someone with a less demanding application may get use out of them.
Anyways, thank you to your valuable contribution to our group!
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#33
(01-28-2019, 12:31 AM)jm1 Wrote: Actually all recovered cells perform great for me with only the exception of the green sony's and red sanyo's.  I guess they are not designed for higher current as you mentioned.  I will have approximately 100-200 of those packs for sale soon because even though they dont work for me, someone with a less demanding application may get use out of them.
Anyways, thank you to your valuable contribution to our group!

well thankyou for your kind words sir.  everyone uses the 'rating' button, right? LOL.

2007 !!!  wow... and I thought my supply was old ... you win!

As for the green sony's and red sanyo's ... yes ... funny you say that, as 90% of my old heaters I used to get were them.  but not so consistently as you.  I now recognise that only when I was 'rushing' their precharge this would happen ... so I concluded that:

these cells in particular dont like going low, IE need kid gloves to bring them back.

I did read somewhere that the sanyos had an electrolyte that was old-tech and well recognised to be inferior to the new, now common standard for electrolyte ... but damned if I can remember where I read that.  Anyone?  I think it might be relevant here ...
--    ----    ----    ----    ----    ----    ----    ----    ----    ----    --
all systems nominal... rock on.
-----------------------------------------------------------------------
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#34
(01-27-2019, 09:51 PM)camthecam Wrote: I know I would try and rescue the low IR ones. I have quite a few that never survived, but the sub 95IR ones are quite good. (time will tell).
camthecam,
Yes but what's really funny is the ones I charged at 500mA look at the IR after the charge it has reduced dramatically.

I should have initial first test capacity hopefully before I go to bed tonight.  
The cells that are being charged with CC/CV at 50mA are still percolating along and they are at 3.77V.
They should be done probably tomorrow and into the tester they will go.

You can view my progress here https://drive.google.com/open?id=1uPdbmv...hwg342k8g3

Wolf
DCkiwi and camthecam like this post
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
So the first couple of cells have been tested and here are the results.

So far all the cells are nicely over 80% percent of capacity. 19 -22 are on their second test cycle.
The CC/CV are still percolating at 3.78 V if that doesn't change much this evening I will put those into the XTAR and charge to 4.2V at 500mA.
Don't worry JM1 I have a special set of cells reserved for your 1A test. Smile

That's all I have for now.

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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#36
As I read this blog it looks these are all old laptop cells. I have mostly only power tool cells US18650 V - VTC3 - VTC5 and w even a couple of VTC6. They are also green. -Smile

The 5 and 6 are 2600/3000 mAh and can handle currents. Great for mobility packs. I got 80% above 95% of them.



Vapors love them too.
DCkiwi likes this post
Menno
Using 7S80P pack. Building 14S40P packs.
"Tell me, and will I forget. Show me, and I may remember. Involve me, and I will understand." Confucius 450 BC
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#37
Damn that's nice.

VTC series of cells are high power cells in general.
The power of lithium ion is in our hands!
We'll show them what we're made of!
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#38
Slowly moving along
I have dedicated 3 Testers to this project so it will be slowly moving along.

Results so far. 



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
#39
(01-30-2019, 12:11 PM)Wolf Wrote: Slowly moving along
I have dedicated 3 Testers to this project so it will be slowly moving along.

Results so far. 



Wolf

that changing IR is very interesting..
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#40
(01-30-2019, 09:33 PM)camthecam Wrote: that changing IR is very interesting..

Yes I agree I have noticed some change with V but that is to be expected but these really change a lot.
Here is a sample of IR change of some random low V cells that I have abused, I guess, with 1A and 500mA charging.
Nevertheless the IR doesn't change that much. Curious Huh




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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