Are we all getting GRADE B cells??

S Davis

Solar Addict
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Sep 25, 2021
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204
I just tested capacity on another set of four LF280N from Docan, top balanced let settle for 30 min and used a Samlex 300watt PSW inverter to draw 25 amps. I got 11 hours 12 min, until the samlex hit low voltage.
 

Warpspeed

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Jun 11, 2021
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328
There is another way of looking at this A+ and A- battery business from the manufacturers point of view.

There will be a market for first class A+ batteries from the elite EV market, and a market for the A- batteries from us unwashed solar peons.

Now the battery factory must continuously tweak their quality control to be good enough to meet the A+ market. They will make all their batteries as good as they possibly can.
But after a few years at this, they get REALLY good at the technology and quality control, and suppose the peon market for the A- batteries has also grown beyong expectations.

They might end up having an excess of A+ batteries, which they sell as A- just to fulfill customer demand.
So rather than becoming paranoid about all this, we might unknowingly be getting a really good deal...
 

Alkaline

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Jul 26, 2020
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356
There is no such thing as A-, A, B+ or whatever fantasy grade people want to come up with. Its either pass or fail. All the documentation and specs sheets you read about are for batteries that are EV Grade or Genuine A, all other so called grading is complete BS people just make up they have no standard to go by, it could be anything.

People just have this fake rolex mentality thinking ohh yeah, Its almost as good... It isn't.

This is what you have to expect, there is no guarantees when you buy reject sells, stop drinking the Kool-Aid the grade B seller is trying to give you, instead play the grade B strategy:

Buy 10-20% more than you need, pick the best from the lot you have and then just hope for the best, hopefully you will come out ahead vs buying grade A, but you have to be willing to put in the work. For most people they will end up saving more going this route than buying grade A cells and that is the dominant approach many people on this forum will take because the cost of grade A doesn't justify the benefit for off grid remote power.

On the flip side If you are just going to throw caution to the wind and just assume you just got a deal, then you are going to be end up looking like a sucker. Because without proper testing and sorting of grade B cells your pack is going to eventually cause issues with IR, not matching and balancing, Very very unlikely you hit the grade B jackpot where all of your cells just happen to be about the same.


Plenty of people have made decent grade B setups but they had to run cell tests, match the cells, themselves and sometimes even have to ditch a few because of issues.

If you don't have the time or resources to do this leg work, then don't' mess with grade B, either buy a retail ready to use battery or buy grade A cells.
 

Warpspeed

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Jun 11, 2021
Messages
328
Have to agree.
If the cells are properly top balanced, that is where they should spend most of their life, in the upper most section of the curve.
What happens in the last ten to fifteen percent down near full discharge, I do not care.
They will never get down that far, because with my system at <3.10 volts a voltage regulated grid powered rectifier kicks in.

Below 3.00 volts the battery undervoltage disconnect operates.

Before I had any battery at all, my inverter ran off solar direct during the day, and from my big dc grid powered rectifier at night.
That worked great for a long time. Its the best possible way to reduce power bills at minimal cost.

And if my battery gets right down, it reverts to the old system. When the sun returns it goes back to solar during the day and battery at night.
 

lfpinside

Gobel Power
Joined
Dec 6, 2021
Messages
39
Location
China
There is no such thing as A-, A, B+ or whatever fantasy grade people want to come up with. Its either pass or fail. All the documentation and specs sheets you read about are for batteries that are EV Grade or Genuine A, all other so called grading is complete BS people just make up they have no standard to go by, it could be anything.

People just have this fake rolex mentality thinking ohh yeah, Its almost as good... It isn't.

This is what you have to expect, there is no guarantees when you buy reject sells, stop drinking the Kool-Aid the grade B seller is trying to give you, instead play the grade B strategy:

Buy 10-20% more than you need, pick the best from the lot you have and then just hope for the best, hopefully you will come out ahead vs buying grade A, but you have to be willing to put in the work. For most people they will end up saving more going this route than buying grade A cells and that is the dominant approach many people on this forum will take because the cost of grade A doesn't justify the benefit for off grid remote power.

On the flip side If you are just going to throw caution to the wind and just assume you just got a deal, then you are going to be end up looking like a sucker. Because without proper testing and sorting of grade B cells your pack is going to eventually cause issues with IR, not matching and balancing, Very very unlikely you hit the grade B jackpot where all of your cells just happen to be about the same.


Plenty of people have made decent grade B setups but they had to run cell tests, match the cells, themselves and sometimes even have to ditch a few because of issues.

If you don't have the time or resources to do this leg work, then don't' mess with grade B, either buy a retail ready to use battery or buy grade A cells.

I agree with this part "There is no such thing as A-, A, B+ or whatever fantasy grade people want to come up with. "

May not "It's either pass or fail."

What is pass or fail standards? If it is the EV factory's matching standard, then so-called 'grade B' cells are good cells, they just do not match the main group.

If fail standards is the cell has a quality issue, then EVE should have been bankrupted. This defective rate is too high. According to a report, CATL has a 0.1% defective rate, only 1000 cells have quality issues in 1 million cells.
 

Alkaline

Solar Addict
Joined
Jul 26, 2020
Messages
356
Grade B vs Grade A


/start sarcasm
But the seller says they are Grade A on AliExpress
/end sarcasm
That guy hates all lithium batteries IMO one of his biggest video is the lithium myth.

That being said what he said in his video is true regarding the spreadsheet and testing.
 

Alkaline

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Joined
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Messages
356
I agree with this part "There is no such thing as A-, A, B+ or whatever fantasy grade people want to come up with. "

May not "It's either pass or fail."

What is pass or fail standards? If it is the EV factory's matching standard, then so-called 'grade B' cells are good cells, they just do not match the main group.

If fail standards is the cell has a quality issue, then EVE should have been bankrupted. This defective rate is too high. According to a report, CATL has a 0.1% defective rate, only 1000 cells have quality issues in 1 million cells.
Where are you getting this info? I talked with Lampard Li and Amy Wan both said on the large cells the failure rate can be as high as 3%, the more watt/hour / lb the higher the failure rate is.

EVE is a very small player vs CATL, CALB, Ganfeng, they don't even run there factory every day, IN fact most of there batches are under 7000 pcs/production run.

Maybe you are thinking about the OLD chunky boy CALB 100AH cells, they probably had a .1% failure rate.

The more watthour/kg / lb is the higher its failure rate and it will get higher as they cram more and more AH into the same volume.
 

robby

Photon Vampire
Joined
May 1, 2021
Messages
2,080
There is no such thing as A-, A, B+ or whatever fantasy grade people want to come up with. Its either pass or fail. All the documentation and specs sheets you read about are for batteries that are EV Grade or Genuine A, all other so called grading is complete BS people just make up they have no standard to go by, it could be anything.

People just have this fake rolex mentality thinking ohh yeah, Its almost as good... It isn't.

This is what you have to expect, there is no guarantees when you buy reject sells, stop drinking the Kool-Aid the grade B seller is trying to give you, instead play the grade B strategy:
It's nice to see the Forum members have stopped becoming stooges. When I bought up this topic 6 months ago in two other threads I was declared a Heretic and was literally beaten back to the point where I stopped posting to the threads.

I had Lengthy discussions at the time with Fortress Power, Sol-Ark and EcoDirect and all of them basically said the same thing to me.
If you see a 5KWh 48V Pack for half the Price of a Fortress or Simpliphi battery then it's Grade B PERIOD!!
Nobody wanted to hear that back then but luckily enough info has come out to prove it to be right

I have now come across another Interesting discovery in that not only do Grade B Packs take about 40% longer to charge than Grade A Packs but they also waste a lot more energy and in my case it got worst after just 6 months of owning the battery.

I am going to make a separate post and link it here: https://diysolarforum.com/threads/o...y-bms-and-wasted-energy-while-charging.42244/
 
Last edited:

Alkaline

Solar Addict
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Messages
356
It's nice to see the Forum members have stopped becoming stooges. When I bought up this topic 6 months ago in two other threads I was declared a Heretic and was literally beaten back to the point where I stopped posting to the threads.

I had Lengthy discussions at the time with Fortress Power, Sol-Ark and EcoDirect and all of them basically said the same thing to me.
If you see a 5KWh 48V Pack for half the Price of a Fortress or Simpliphi battery then it's Grade B PERIOD!!
Nobody wanted to hear that back then but luckily enough info has come out to prove it to be right

I have now come across another Interesting discovery in that not only do Grade B Packs take about 40% longer to charge than Grade A Packs but they also waste a lot more energy and in my case it got worst after just 6 months of owning the battery.

I am going to make a separate post and link it here:

Yes I agree but my conclusion was with my own experiences with Xuba and Basen.

Speaking off Andy just made 2 nice videos going into this:


&


I think people just need to come to the realization you get what you pay for.
 

robby

Photon Vampire
Joined
May 1, 2021
Messages
2,080
Yes I agree but my conclusion was with my own experiences with Xuba and Basen.

Speaking off Andy just made 2 nice videos going into this:


&


I think people just need to come to the realization you get what you pay for.
I did not watch the second video yet but one of the things that he did not mention in the first video is that capacity is not the primary reason why cells get rejected. The number one reason is "Slitting" problems in the cells.

The machine that cuts the the strips of aluminum and copper will not always make a clean cut and the edges of these strips will have ragged sharp edges.
The strips are kept apart by separators that will get damaged if the edges are not smooth. Every charge and discharge cycle causes abrasion on the seperator due to the expansion and contraction involved. If the edge is not smooth it cuts into the seperator and causes arcing. This is why X-Rays are done on the finished cells to see if any slitting problems are present.
This slitting problem is what causes the batteries to develop a higher internal discharge rates which then leads to a rapid loss of useful capacity during a much shorter time period.
 

Don B. Cilly

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Mallorca ES
Well, that sounds a bit... I mean, if something as simple as rough edges causes serious defects, how difficult can it be to have the edges filed, as part of the same machine or the next one down the line? Not conceivably difficult or expensive, right? Certainly less expensive than rejected cells.
-
 

justgary

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Well, that sounds a bit... I mean, if something as simple as rough edges causes serious defects, how difficult can it be to have the edges filed, as part of the same machine or the next one down the line? Not conceivably difficult or expensive, right? Certainly less expensive than rejected cells.
-
Filing the edge of aluminum foil is not the simplest thing to do. They are talking about microscopic tears, and any sort of mechanical treatment would probably make it worse. I can see how a laser might be used to ball the edge slightly and make it less sharp, but then the thickness would change and build up over many layers.
 

curiouscarbon

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Jun 29, 2020
Messages
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I did not watch the second video yet but one of the things that he did not mention in the first video is that capacity is not the primary reason why cells get rejected. The number one reason is "Slitting" problems in the cells.

The machine that cuts the the strips of aluminum and copper will not always make a clean cut and the edges of these strips will have ragged sharp edges.
The strips are kept apart by separators that will get damaged if the edges are not smooth. Every charge and discharge cycle causes abrasion on the seperator due to the expansion and contraction involved. If the edge is not smooth it cuts into the seperator and causes arcing. This is why X-Rays are done on the finished cells to see if any slitting problems are present.
This slitting problem is what causes the batteries to develop a higher internal discharge rates which then leads to a rapid loss of useful capacity during a much shorter time period.
very interesting insight on this mechanism of failure mode!

thank you!
 

Bvillebob

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Oct 21, 2021
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295
On the one had I agree there is no Grade A or B, it's just marketing. On the other hand in the last few months I've seen this forum fill up with FUD (fear, uncertainty and doubt) generated by vendors intended to slam other vendors, like the line above that "Grade B" cells only charge at half the speed of "Grade A" cells, and I suspect the stuff about "slitting issues". It's perfectly possible for a cell to fail to meet the EV standards while still being fully acceptable for solar use, completely different applications.

In an effort to try to make themselves stand out some vendors are filling the internet with trash about their competitors, to the point that a newbie has no idea of who to believe. I'm sure some of them will opt for the high priced options based on the fearmongering going around, but many more will just say to heck with it.

This behavior is hurting the whole industry, as much as the fly by night vendors promising "Grade A" cells for $50 each.
 

Alkaline

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All of these prismatic cells on the market were made for Electric Vehicles, it should be clear by now if you look at there data sheet that was the intended purpose. They also are clearly set a testing standard to meet.

This Grade A vs Grade B debate no longer exist:

The manufacturer is going to start Marking the cells as Grade B on the qr code on cells that do not meet there testing standard, so anyone denying there is no such thing as grade A vs Grade B will will have to stare at a Big fat B on there cell.
 

curiouscarbon

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All of these prismatic cells on the market were made for Electric Vehicles, it should be clear by now if you look at there data sheet that was the intended purpose. They also are clearly set a testing standard to meet.

This Grade A vs Grade B debate no longer exist:

The manufacturer is going to start Marking the cells as Grade B on the qr code on cells that do not meet there testing standard, so anyone denying there is no such thing as grade A vs Grade B will will have to stare at a Big fat B on there cell.
the pictures in the thread were helpful :) thanks for sharing
1656457022209.jpeg
 

S Davis

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Sep 25, 2021
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So where is the spec sheet for grade B? As long as there is no spec sheet it is a failed top grade(grade a if you like). With no idea why it failed it could be grade F😉
 

burgerking

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Apr 6, 2022
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Subic, Philippines
There is no Grade A, there is no Grade B, there is no Grade C.

So what if EVE laser etched "B" on the QRCode. That means sold to Basen!
EVE will etch "D" for Ducan and "Q" for Qishou!

Satisfied? Move on.

If not satisfied, buy from Liitokala. All QRCodes are erased by sanding them off. Nothing to discriminate if they are A or B or F!
 
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