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Harvested cells analysis.
#31
Spent all weekend in the shed harvesting cells. Had to make room as this Friday I am making my trip for 200 packs again. 
Pretty Good results on the harvest for >3V not so good on the >2V to <3V ( I have found that the cells in this V range seem to be the ones that produce the best results after a proper waking up charge) and a lot of <2V to 0V ones. 


I managed to get past the 3000 (3203) recorded cell mark and have almost hit my ½ cell mark of 2800 with 1332 cells at ≥2200mAh, ≥80% of Capacity and ≤75mΩ of IR. 


Now I am excited and looking forward to hit the 5000 recorded cell mark. Talk about a database that is enlightening, I never thought that so much information could be gleaned from this. The cool thing is that as my powerwall ages I will be able to look up the cells by number and see how they aged and what has changed in them if anything.
Well onward and forward

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 5/23/2019
Total Number of Cells                          5354
Cells  >80% of Capacity                      3801
Cells <80% of Capacity                       1553
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2645 (155) to go
For Info Google Drive
Not your average Wolf       
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#32
(03-05-2019, 02:42 PM)Wolf Wrote: I will add to this chart another test again of 4 all brand new Sony VT4 18650 2100mAh 22A Batteries I just ordered. I will run them through the SKYRC first and then all the others I have. 
The results of running 4 brand new Sony US18650VT4 cells through all my testers except the Zanflairs
Quite interesting results The max was on one of the LiitoKala at 2247mAh (107.00%)
and the min was on a Foxnovo at 1996mAh (95.05%)
The SKYRC as far as I am concerned was dead on both times with both test parameters. One test at cell manufactures C/D specs and one test with the generic 500mA C/D parameters
The LiitoKala was slightly high as was the Opus but not by much.
The Foxnovo was darn close but slightly low on a couple.
Total results out of 48 tests is an average result of all testers combined at 101.35%.
What that tells me is if I put 48 random cells into these testers the end result is a 1.35% deviation on the positive side of capacity
I can live with that.
Comments, questions, disagreements all welcome. 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 5/23/2019
Total Number of Cells                          5354
Cells  >80% of Capacity                      3801
Cells <80% of Capacity                       1553
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2645 (155) to go
For Info Google Drive
Not your average Wolf       
            Cool



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#33
The deviation is 1.35% on that brand and cell type though... If you want it on overall you need to run that number on all ur cells tested so far Wink
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#34
(03-13-2019, 11:40 AM)daromer Wrote: The deviation is 1.35% on that brand and cell type though... If you want it on overall you need to run that number on all ur cells tested so far Wink

Good one!!
I don't think I have the chargers and or the space to do that.
Granted the cells are new but it does show the deviation of the testers and as a lump sum together it is not that bad.
But what I can do is take a random sample of 4 harvested cells of different manufactures and repeat the test. Would you say that is a good start?
I can then always pick 4 random cells and dedicate 1 tester in series to continue this for a while at least till we see concrete results one way or the other. After I get done with my "Sony green cells suck analysys" to which I have dedicated 1 tester to I can cycle in that one and we will see what we will come up with.
It will also show what effect cycling the cells 12 times has on the capacity degradation if any.

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 5/23/2019
Total Number of Cells                          5354
Cells  >80% of Capacity                      3801
Cells <80% of Capacity                       1553
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2645 (155) to go
For Info Google Drive
Not your average Wolf       
            Cool



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#35
I think thats a good start for sure!

The 95-107 is also important to compare towards each of the testers because that number is in line with the 10% that I have stated since early days and potentially confirms that too.
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#36
(03-13-2019, 01:36 PM)daromer Wrote: I think thats a good start for sure!

The 95-107 is also important to compare towards each of the testers because that number is in line with the 10% that I have stated since early days and potentially confirms that too.

I agree on a cell by cell comparison but when you combine all the results the deviation is minimal. In essence one cancels the other.
1 95% cell and 1 107% cell  equals 101%. So I am doing that with my range of testers and the Opus and LiitoKala being ~25% really close and ~75% slightly high, additionally the Foxnovo ~75% slightly low and ~25% dead on along with the SKYRC I can pretty much be happy with my "Averaged" results.
Now trusting the SKYRC MC3000 to be as accurate as the manufacturer describes "at lab conditions". I do believe we have at least a baseline tool for accuracy to use. Got to trust something.

As Kori said in a post a while back more testing more testing. LOL

Just like I made sure my Fluke meter was right on. 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 5/23/2019
Total Number of Cells                          5354
Cells  >80% of Capacity                      3801
Cells <80% of Capacity                       1553
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2645 (155) to go
For Info Google Drive
Not your average Wolf       
            Cool



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#37
Reference my earlier question on how long do Li-ion cells last - I found this link: https://www.solar-estimate.org/news/2018...eries-last
At the bottom is a section "What's the lifespan of a lithium-ion battery" with...
1) A link to a PDF with scientific test details on Grid-Connected Li-ion -    https://www.nrel.gov/docs/fy17osti/67102.pdf
2) A recap on that says this (from the test details):
Under NREL's scenarios, an energy storage system is expected to last between seven and 10 years. "Without active thermal management, 7 years lifetime is possible provided the battery is cycled within a restricted 47% DOD operating range. With active thermal management, 10 years lifetime is possible provided the battery is cycled within a restricted 54% operating range," NREL said.
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#38
(03-14-2019, 10:36 AM)OffGridInTheCity Wrote: Under NREL's scenarios, an energy storage system is expected to last between seven and 10 years. "Without active thermal management, 7 years lifetime is possible provided the battery is cycled within a restricted 47% DOD operating range. With active thermal management, 10 years lifetime is possible provided the battery is cycled within a restricted 54% operating range," NREL said.

I assume that that is starting out with brand new batteries.
But still all in all a good life cycle.
To achieve a 47% DOD with harvested cells plan big or go home. Big Grin
I for one in that sense am not going home 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 5/23/2019
Total Number of Cells                          5354
Cells  >80% of Capacity                      3801
Cells <80% of Capacity                       1553
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2645 (155) to go
For Info Google Drive
Not your average Wolf       
            Cool



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#39
@wolf
If you need extra space, come over to the Netherlands, I have a very nice big shed, you can make youre own corner there.

I am not difficult with rent, 500 cells per month(-:

@Offgridinthecity, thanks for the info!
Wolf likes this post
Still learning English. Learning Li ion and solar technology.
+/- 3500 Li ion cells harvested, none checked and counting.

Time is our enemy, must work to, the sun is our friend, must relax to.
With best regards
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#40
(03-14-2019, 12:53 PM)100kwh-hunter Wrote: @wolf
If you need extra space, come over to the Netherlands, I have a very nice big shed, you can make youre own corner there.

I am not difficult with rent, 500 cells per month(-:
100kWh
My shipping container will arrive in a month or so.  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 5/23/2019
Total Number of Cells                          5354
Cells  >80% of Capacity                      3801
Cells <80% of Capacity                       1553
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2645 (155) to go
For Info Google Drive
Not your average Wolf       
            Cool



Reply


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