codes on lifepo4 cells

[100kwh-hunter]

In various threads i read upon the qr stickers codes numbers ect and what they could mean.
I think to decipher those codes on the cells is possible, probably simple mathematics-------> i said *probably*!!!

If we take into account that there are a b c grade cells and add storage time, witch mean degradation it could be in this number.
Also there old calendars use 13 months sometimes 14 months, due to the setting of the moon, and they live in the year 4900? somewhere?
I have a strong suspicion that the first 3 digits is the batch number. incl a alphabet number would give a factor of 26.
and the middle are correlated with a date, the last two could be a amount of cell produce x 1000?

Any thought on my theory? or other thoughts/comment/idea's are very welcome, i like a good challenge.
With best regards Igor

 

[ArthurEld]

As far as I know, nobody has been able to crack the date code.

There's a new format on some cells too



edit: thread where decoder came from - https://diysolarforum.com/threads/12v-280ah-lifepo4-battery-build-and-test.8467/post-115837

 

[100kwh-hunter]

I was not far off...YO THO WOW....
I think you are the key master.
There goes my challenge(got a big ass smile on my face now btw)

What do you think or know about the a b or c grade labeled cells?
I think a grade is new unused.
b grade is one year old
c grade is probably used for one year in a ess device and then the ess is replaced with new cells, then the cells are refurbished.
But with c i am not sure, could be also 2 or three years of age.
Or worse ex refurbish ev battery's....

Your 87c is very precise, to precise for my taste: july 12 2018...1.5 almost 2 year old cell(age degradation).
I think it is the date weekly/monthly assembled batch for lifepo4 chemicals, cous for that precision date there must be more numbers if it was implying the production date of cells.

Lets say the number 87 is the number of months that this factory is spitting out cells and the c stands for the third quarter of the year, so the factory line could exist to there calendar: 13 to 15 years, our calendar 10 to 12.5 years
The next digit: 0 to 9 a b and c
If we take into account that the a and b could represent november and december so within two years we will see a c as a month?
Oke
But i toke the next digit in your key the "c" for a quarter of the year, this could also mean the batch letter of the chemicals, i think i will stick to the batch number/letter of the chemicals.
Main reason: they are putting a lot of effort to get every batch to be send of as close as possible in there ir, why would they be showing it off in the first place, i mean it is a production line, a batch of chemicals mixed what could go wrong instead of aging?!?!?
And the letters are beyond k.
Ill stick to the batch of chemicals produced in that particular year and not the quarter of a year
I have an idea about this chemical batch, mainly the: why they produce it, but i wont over complicated this, more later on this.
I noticed also that there(all chinesum cells btw) new a grade cells are never coming back in the same capacity, if you order every 3 months, try to order the *same* capacity from last year.

Oke the why, those factory's produce that kind of amount of cells they can not sell all the cells to the privet market alone, they simply produce to much.
The batches of chemicals are mixed at demands for company's at demand for there particular use, the left overs or slight out of the company's tolerances will be sold of to the privet market.
It is simply to costly to mix to little for one company so mix more, it is to expensive to throw it away so mix some extra to be suited for the privet market, money and merchandise wise this is very cost effective and with a good profit, group buy a 10000 cells to your specs.....could be very rewarding.


Thanks for reading, any thoughts/ideas/comments are appreciated, if i am wrong or you have other thoughts just be honest, just tell me, no hard feelings.
With best regards Igor, thanks in advance

 

[100kwh-hunter]

found the pdf file in the thread you give me, thanks.

 

[ArthurEld]

I don't think there is an official grading system for the cells we buy.
If you are nice to the person selling to you and pay the going price you will probably get good cells.
If you treat the seller with disrespect or try to buy sells for less than the going rate you will probably get the cells they have been saving for you.

edit: of course you have to deal with reputable sellers

 

[100kwh-hunter]

I agree.
But the a b and c grade cells are graded for a quality reason.
It is age or chemical composition, not referring to 1 to 3 or even 5 c discharge.
i have read upon some c grade cells, usually they are refurbish and or misfits or second hand (slightly) used cells.

 

[Gazoo]

I agree.
But the a b and c grade cells are graded for a quality reason.
It is age or chemical composition, not referring to 1 to 3 or even 5 c discharge.
i have read upon some c grade cells, usually they are refurbish and or misfits or second hand (slightly) used cells.

Nobody knows what cell grading means or how the suppliers arrive at it. As far as I know all suppliers claim grade A for the EVE cells. We know they are not grade A unless purchased directly from EVE. I read one of the suppliers rates their EVE cells grade A-5. But we don't know what that means. It would be nice to know the different grades but I am not sure there is any standard. One supplier might rate their cells grade B and another might rate that same cell grade C....for example. As far as the date code on the EVE cells, EVE has stated they are the only ones that can decipher it.