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BATTERY SELLERS - THE GOOD, BAD, UGLY -- or Jenny (DOCAN) so far so good ...

However her latest response to me said that only Grade A cells can pull full capacity.
Cell capacity is one small piece of the puzzle for a component that is designed to work in sync with 4, 8, 16+ counterparts for 10+ years.. The vast majority of Grade B cells can indeed pull full capacity.
Yes I agree. so to me that means that Docan considers any cell grade A that can pull full capacity.. so that is most likely why they remove or cover up the original QR code,, to make the cells still seem like grade A even though though they are most likely grade B. Grade B because they didn’t meet CATLs strict EV requirements..
I think what Docan is saying is that if the batteries supply full capacity then why can’t they be considered grade A.. Even if they were not good enough to pass CATL test for EVs.. I think Docan is also saying that to be considered grade B the cells would not supply full capacity.. so Docans criteria for grade A for solar storage cells is simply if the cells pull full capacity.. TBH for solar storage, supplying full capacity is basically all that matters. As long as there isn’t any runners that can’t be balanced out, then for solar storage Docans grade A (actually grade B from CATL) are fine with me and I suspect fine for most solar storage applications.

So they cover up the scratched off QR codes because for solar storage application the cells pull full capacity and therefore are still considered grade A to Doncan.. I paid only $105 per cell so obviously these are not EV grade cells, they are solar storage grade..
 
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I paid only $105 per cell so obviously these are not EV grade cells, they are solar storage grade..
If that's total cost with fees and shipped to your door, that's fantastic! In fact, I'll build another battery or two at that price! If not, then I guess you paid more than $105. :unsure:
 
Yeah cheapest I see is 105 + shipping + sales tax + ali transaction fee = closer to $135/cell, which is why buying direct from Houston warehouse would make more sense as its only $60.00 more for a 4 pack.

That being said I am not doing DIY as I believe its cheaper to buy retail batts (for my needs).
 
If that's total cost with fees and shipped to your door, that's fantastic! In fact, I'll build another battery or two at that price! If not, then I guess you paid more than $105. :unsure:
Total was $2450 for 19 cells. $128 each cell. $105 before fees etc. buying from local warehouse wasn't an option. They didn’t have any in the states. Wasn’t going to be any for a while from what Amy said. Also it was I think $650 for 4 cells ($162 each) and I needed 19 so not in multiples of 4.. All in for 17kwh, bms, spring compression, laminated flexible busbars it was $2750ish.. it costs over $3k for only 10kwh of the cheapest server rack.. although I understand many reasons for not DIYing
 
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Glad I found this thread about the catl280 side QR code. I have 8 of those exact cells on order from Docan but there was a delay in shipping. I was offered the EVE 280k instead for the same price, but turned them down because of all the negatives I've read about the eve280k having low capacity and arriving bloated. I am more concerned with them being used or refurbished somehow, with the new black covers and QR code, if that makes sense. Does anyone have an opinion on which is the bigger risk, these CATL 280 with non factory QR code or the EVE280k that seem to be mostly swollen and fall short on capacity? I was still leaning toward the CATL, as I've read almost all positive accounts, but now I am wondering if I made the right choice.
 
If you want certainty, you'll have to pay the price and get EV grade. Otherwise its a toss up either way.
 
Glad I found this thread about the catl280 side QR code. I have 8 of those exact cells on order from Docan but there was a delay in shipping. I was offered the EVE 280k instead for the same price, but turned them down because of all the negatives I've read about the eve280k having low capacity and arriving bloated. I am more concerned with them being used or refurbished somehow, with the new black covers and QR code, if that makes sense. Does anyone have an opinion on which is the bigger risk, these CATL 280 with non factory QR code or the EVE280k that seem to be mostly swollen and fall short on capacity? I was still leaning toward the CATL, as I've read almost all positive accounts, but now I am wondering if I made the right choice.
My opinion, Used or refurbished I highly doubt.. just new cells that were not good enough for CATL or EVE to use for EVs. Still good enough for solar storage.
 
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Glad I found this thread about the catl280 side QR code. I have 8 of those exact cells on order from Docan but there was a delay in shipping. I was offered the EVE 280k instead for the same price, but turned them down because of all the negatives I've read about the eve280k having low capacity and arriving bloated. I am more concerned with them being used or refurbished somehow, with the new black covers and QR code, if that makes sense. Does anyone have an opinion on which is the bigger risk, these CATL 280 with non factory QR code or the EVE280k that seem to be mostly swollen and fall short on capacity? I was still leaning toward the CATL, as I've read almost all positive accounts, but now I am wondering if I made the right choice.
I am one of those who receive "bloated LF280K" and i can tell you that they don't have low capacity and soo far they work perfect.
 
post your test results both WH and AH Its always good to get as much data as we can.
 
This EV grade vs energy storage grade is non-sense. Don't fool yourself or others with this terminology. Docan wants to confuse you, that's how they can ask a premium for trash. They are either deemed suitable for battery pack or they are not.
This makes no sense to me.. what other terminology would you suggest. There is obviously cells that do not meet the manufacturers strict EV requirements. That can be because they have more than rated capacity or less because all the cells in the EV packs need to be the exact same. Or other parts of the puzzle you mention that are not quite up to spec or exactly the same for EVs.. those are the cells that most on this forum and apparently most everywhere are buying for solar storage.. they are suitable for solar storage battery packs.. not every cell as there’s sometimes bad cells that won’t play nice with other cells. That would of course occur more often with the cells that didn’t meet up to the manufacturers EV specs.. from what I read Docan will simply replace those cells if you happen to get one..
 
This makes no sense to me.. what other terminology would you suggest. There is obviously cells that do not meet the manufacturers strict EV requirements. That can be because they have more than rated capacity or less because all the cells in the EV packs need to be the exact same. Or other parts of the puzzle you mention that are not quite up to spec or exactly the same for EVs.. those are the cells that most on this forum and apparently most everywhere are buying for solar storage.. they are suitable for solar storage battery packs.. not every cell as there’s sometimes bad cells that won’t play nice with other cells. That would of course occur more often with the cells that didn’t meet up to the manufacturers EV specs.. from what I read Docan will simply replace those cells if you happen to get one..
I agree, granted I have not received my cells yet. I would assume in the EV industry, physical space is very limited, so I could also believe they would reject any cell that does not meet the maximum AH/size they set forth.

As far as these side code catl 280ah that are measuring upwards of 300ah I suspect they are really the 304ah cells that failed to reach full capacity during the EV tests, so they mark them as 280ah, put a new black top with QR code and slightly lower price for DIY. As far as I can tell the physical sizes of these 280ah side codes are the same as the 302ah cells but cannot confirm. Has anyone else already come to this conclusion? I will hopefully get my cells in the next couple weeks and will update test results when I do.

Of course I am new to the DIY cells so I could be totally out in left field.
 
@Alkaline directed me to this thread. I'm in the same situation - CATL 280Ah cells are on their way. I got a bit afraid of what I'll be getting if these have fake QR codes.

I googled a bit the CB310 and found other pictures (not from Docan) with the same QR code position. Moreover - the video below is a year-old video for the same QR code location, but for cells ordered from Aliexpress. Another image pointed me to Facebook and it directed me to a page that is related to "evlithium", no trace of Docan there.

So it is unlikely that Docan is doing this. To me, it seems more likely a CATL thing. Otherwise, it would be a great conspiracy theory that multiple resellers are putting fake QR codes the same way. Think a bit about it. If you can create a fake QR code why not put it in the same place as the original one?

So as long as the cells are not bloated and they pool the stated capacity I would be fine. Yep, I understand the common impression that we are getting grade B cells, but this is just an impression. Only time will show if our cells are good or not.

 
I just want some clarification but is DONCAN and DOCAN the same company? I just realized form the title of the thread.
 
It is a typo. I see people use both but still refer to the same salespersons. Moreover - there is no Doncan seller on Alibaba. The full name is "Docan Technology(ShenZhen) CO.,Ltd.".
 
@Alkaline directed me to this thread. I'm in the same situation - CATL 280Ah cells are on their way. I got a bit afraid of what I'll be getting if these have fake QR codes.

I googled a bit the CB310 and found other pictures (not from Docan) with the same QR code position. Moreover - the video below is a year-old video for the same QR code location, but for cells ordered from Aliexpress. Another image pointed me to Facebook and it directed me to a page that is related to "evlithium", no trace of Docan there.

So it is unlikely that Docan is doing this. To me, it seems more likely a CATL thing. Otherwise, it would be a great conspiracy theory that multiple resellers are putting fake QR codes the same way. Think a bit about it. If you can create a fake QR code why not put it in the same place as the original one?

So as long as the cells are not bloated and they pool the stated capacity I would be fine. Yep, I understand the common impression that we are getting grade B cells, but this is just an impression. Only time will show if our cells are good or not.


So here is probably what is happening a wholesaler buys these CATL (cells that failed testing) the wholesaler than applies a FAKE qr code and then sells these to alibaba/express sellers who then sell them to you. So 1 shop probably does the lasering and then supplies the grade B cells to all that are looking to resell.

Sorry but Docan is doing exactly this:

So not needed they can advertise them as Value Grade or Storage Grade and be just fine. But they go around saying TOP GRADE and other stuff. I suppose it works only 1/10 people will actually test probably 1/20.

BTW people have tested the CATL 280 they are pulling close to the rated 280AH from Docan.
 
BTW people have tested the CATL 280 they are pulling close to the rated 280AH from Docan.

This is not sufficient to mark a cell as good. What is equally (or even more) important than capacity is internal resistance. But if IR and capacity are fine - then I consider these as grade A cells on my scale.

Capacity life is another story. I'm living it outside the picture for now. The only way to see if we got crappy short-life cells is to wait a couple of years.
 
Voltage slump is also important, what’s the point of having a 280ah pack if you can’t pull more than 50a before voltage starts to go to trash after 100ah or so.
 
Voltage slump is also important, what’s the point of having a 280ah pack if you can’t pull more than 50a before voltage starts to go to trash after 100ah or so.

Voltage slump is caused by high IR.

IR is not constant. It changes with SOC and temperature. And these are affected by the load. The higher the SOC is, the higher the IR gets. The colder the cell is - the higher the IR gets. So batching of cells should be done with IR measured at the same SOC and temperature. Usually ~30-40 SOC (as this is when it matters more).
 
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