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Harvested cells analysis.
#11
You could also set up a trade as lots of users would be happy to use cells in 2000-2200 range
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#12
(02-28-2019, 05:53 PM)Dallski Wrote: Wolf, if you are already tracking which tester and slot you use to get each test result, I would suggest using correction factors in an additional column to get "true capacity." That way you are not including a 2150 cell and rejecting a 2250 cell if that makes sense. Also, another option for you if you want to include cells down to 2000mAh is to increase your pack size. You can easily add 20P to your 14S 200P by including those 285 cells between 2200 and 2000mAh.

Overmind, I was just referring to the cell topic where Wolf was thinking about upping his minimum cell capacity from 2000mAh to 2200mAh. I don't disagree that a 2000mAh cell could be a good cell. Wolf has 285 cells that are between 2100mAh and 2200mAh. A few mAh here or there can make a big difference in the number of cells that make the cut.

I am tracking which tester but not which slot. It can be deduced on some binge charging of same cells as I always have the lowest # on the right.
So to say as an example cell 3692 would be the rightmost slot on the Foxnovo and so on following down the line. but that is not always a sure thing.
Nevertheless I am not that concerned about slot difference as my testing has shown that to be very minimal I mean 4.86% difference between slots at most and that being the LiitoKala as the worst offender. The more I analyse these chargers the more I like my Foxnovos. Smile
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. (Except the Zanflair we already know about that one) recording it all. Lets see what happens with that and go from there.
Adding 20p would be an option for sure.


Wolf

(02-28-2019, 06:45 PM)Chablis_m Wrote: You could also set up a trade as lots of users would be happy to use cells in 2000-2200 range

Yes I certainly can but shipping is the big holdback with that.

I already gave away ~1000 sub 80% cells to someone that lives about an hour away by car.
I will continue to do that and advertise here when I have a large enough lot. As far as the 80% and up sub 2200mAh cells those I will more than likely sell at a reasonable cost at some time in the future.

Wolf
Oz18650 likes this post
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 70mΩ or less Smile
Last count as of 3/20/2019
Total Number of Cells           3619
Cells  >80% of Capacity        2317
Cells <80% of Capacity         1265
Cells ≥2200mAh & ≥ 80%     1590
Google Drive for info https://drive.google.com/drive/folders/1...sp=sharing
Not your average Wolf       
            Cool



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#13
Thanks for documenting and sharing with us all!
beserker786 likes this post
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#14
@Wolf, for ICRs, all new Samsungs from 2600mAh (26F) above officially support over 1A constant discharge. Same probably goes for other manufacturers too. Older ones from all manufacturers indeed are rated for 4-600mAh.
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#15
(03-01-2019, 12:00 PM)Overmind Wrote: @Wolf, for ICRs, all new Samsungs from 2600mAh (26F) above officially support over 1A constant discharge. Same probably goes for other manufacturers too. Older ones from all manufacturers indeed are rated for 4-600mAh.

I certainly agree that these cells can discharge at up to 2.0C 5200mA but will only produce 80% of capacity.
According to the spec sheet for 100% capacity the discharge recommendation is still 0.2C 520mA.

https://www.batteryspace.com/prod-specs/...50-26F.pdf


Wolf
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 70mΩ or less Smile
Last count as of 3/20/2019
Total Number of Cells           3619
Cells  >80% of Capacity        2317
Cells <80% of Capacity         1265
Cells ≥2200mAh & ≥ 80%     1590
Google Drive for info https://drive.google.com/drive/folders/1...sp=sharing
Not your average Wolf       
            Cool



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#16
Good observation. It meas a 1A discharge would need a correction factor since that will measure 97% of capacity.
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#17
(02-28-2019, 07:00 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 Sony US18650VT4 cells have arrived and are now in the SKYRC running their first test.

They arrived with a V of 3.57 each and 19.8mΩ / 20.0mΩ
The standard charge rate is 2000mA and the standard discharge rate is 420mA which is what the SKYRC is doing.
They will then go to each one of my testers and be tested at 500mA C/D.
I will post the results when done.

Wolf
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 70mΩ or less Smile
Last count as of 3/20/2019
Total Number of Cells           3619
Cells  >80% of Capacity        2317
Cells <80% of Capacity         1265
Cells ≥2200mAh & ≥ 80%     1590
Google Drive for info https://drive.google.com/drive/folders/1...sp=sharing
Not your average Wolf       
            Cool



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#18
Hi Wolf,

I hope you don't mind this copie and question, cous i think, i maybe (don't) understand, you wrote:

The cells I am working with mostly are ICR chemistry which most of them (again the exception proves the rule) have a manufacturer's "standard" discharge rate of ~400mA to 600 mA usually .02C of rated capacity. That is also the discharge rate that "most of these batteries" are rated at for their mAh results.
That is not to say that a discharge rate of .5C or even 1C wont produce close to the desired results. But more heat is involved.
More than likely I will keep the INR chemistries and high drain capable cells out of my packs as it will influence the IR of the whole pack by reducing it to an artificially low level. as most of the INR cells have an IR of <30mΩ and the standard ICR cell chemistry usually runs around 50mΩ to 80mΩ.

If i understand this correctly, it is a bad idea to mix laptop cells and powertool/ebike cells together in one pack.
Because a laptop cell has an higher IR and "slows down" the powertool cells.
One ?pack? is 3,7 volts and depending on the amount of cells in the pack, 100 in my case would be 220A
So its better to form a pack alone with laptop cells or alone with powertool cells?
And you can mix different packs to a battery/accu (in my case) 24v? or not, and keep each battery from laptop or from powertool?

Thanks in advance, best
Still learning English. Learning Li ion and solar technology.
+/- 1500 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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#19
(03-07-2019, 06:42 PM)100kwh-hunter Wrote: If i understand this correctly, it is a bad idea to mix laptop cells and powertool/ebike cells together in one pack.
Because a laptop cell has an higher IR and "slows down" the powertool cells.
One ?pack? is 3,7 volts and depending on the amount of cells in the pack, 100 in my case would be 220A
So its better to form a pack alone with laptop cells or alone with powertool cells?
And you can mix different packs to a battery/accu (in my case) 24v? or not, and keep each battery from laptop or from powertool?

Thanks in advance, best
100kWh-hunter,
Good question to which I do not know the complete answer to.
The only thing that I have to go on is my understanding of electrical flow and that is electrons will always choose the path of least resistance.
What does that mean in a pack of 100p? I don't know. Logic says that the lower the resistance the more current will flow through it. If you have cells with a delta of say 50mΩ 50 cells at 30mΩ and 50 cells at 80mΩ what does that mean electrically? I know that the combined resistance of the pack is going to be 1.1mΩ (30mΩ/50=0.6) + (80mΩ/50 =1.6) / 2 =1.1 how does that affect each individual cell?
I do know that manufactures put the same cells into their packs for a reason and that is that the cells all have the same characteristics. As in mAh, IR and chemistry. So as far as I am concerned we are in somewhat uncharted territory but then again that's the fun of it. I do know that if I put 2 resistors in parallel and one is 3Ω and the other is 8Ω more current will flow through the 3Ω resistor. Electrically the parallel pair of resistors equal 5.5Ω. Physically they are different.
Most powertool (but not all) are generally lower capacity (as in 2200mAh or below) but very high drain. which requires them to have a different chemistry ( usually IMR and INR) compared to laptop batteries which tend to be higher capacity 2200mAh and up but low drain( usually ICR).
My thinking is not to mix them but don't take my word for it. As for me the "powertool batteries" that I get I will use in separate packs as in 12V battery packs just to have and to hold. You never know when you need to jumpstart a car. Big Grin  Till someone convinces me otherwise that will be my plan of attack.

Wolf
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 70mΩ or less Smile
Last count as of 3/20/2019
Total Number of Cells           3619
Cells  >80% of Capacity        2317
Cells <80% of Capacity         1265
Cells ≥2200mAh & ≥ 80%     1590
Google Drive for info https://drive.google.com/drive/folders/1...sp=sharing
Not your average Wolf       
            Cool



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#20
@ wolf,
Thank you for you replay, your resistance story sound very familiar and thus logical.
But i wont settle with: storage is storage, just like you.
The last pack,(giving by the amount of cells i have harvested now) will be from power tools, cous for the electric flow.
Its 1/3 laptop and 2/3 powertool/ebike.
I think i will end up this first experiment with 1/15 laptop and 14/15 powertool/ebike cells, so no need yet for laptop cells.

The chemistry story i will have to dig in further, when the time is there

Speaking of to jumpstart the car....that buzzer that is warning you, that you left your lights on, is broke, stopt working two months ago.
I had to jump start several time's, i am not kidding!

Almost forgot, sorry.

How much do we actually drain from each cell? One battery containing 7 packs and every pack a 100 cells and must feed 600w an hour at 230v.
Or we built it up, and go to a battery of 21 pack(3x7), each pack contain 400 cells, and it feeds the same 600watt system at 230v.
Btw both examples are in 24v battery configuration.

Or you need to have big power for a short while(one hour), like for the oven, and you have small capacity.
I think: where and what are youre demands, so that is how you are going to assamble your battery's
Until you have enough ofcourse

However i think the high drain cells must be in one pack and at the and of the electric line.
In other words: the laptop cells must be the first one
Correct me if i am wrong: current flows from - to +

My classes where 30 years ago, have to refresh a lot, i did not do a lot with that knowledge in the meantime.

Most of the writing in this post was thinking out loud, hoping for answers,

thanks in advance
Still learning English. Learning Li ion and solar technology.
+/- 1500 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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