diy solar

diy solar

Supplier defends lower capacity as being within 5% of stated capacity

If you were buying a name-brand product from a North American vendor, and they told you the manufacturer does not offer a warranty with this purchase, would you actually make that purchase? If your answer is "no," then you don't consistently apply your philosophy with these grey market cells.
maybe. My first question is why isn’t it warranted, my next question is what kind of price break?
 
90%

China suppliers lie. Period. They will try to get away with whatever they think they can. They will tell you what you want to hear. I've made several purchases over the years, and I'm constantly contacted by Chinese suppliers pedaling junk. I have the data showing how inferior their product is, and they will just deny it over and over and claim how widespread and successful their product is.

If you believe that you are purchasing "Grade A" cells from suppliers off Alibaba for a small fraction of the going price, you are gullible and have horribly unrealistic expectations. To believe that your standards of "honesty" apply in dealings with China based suppliers is just a misplaced sense of entitlement and disillusionment with how you think the world should be instead of how the world really is.

China: Buyer Beware. Always. Every. Single. Time.
From my experience, this couldn't be any closer to the truth. My first batch of CA100 cells from Jimmy Xie (AUK) got me and my friend ripped off on a buy of 32 cells! Not only were the used and didn't test out to capacity, the busbar laminations that CALB provides were cut apart to make way thinner and smaller bars, nowhere even close to appropriate for the ampacity of batteries.

Is everyone using calibrated test equipment?
Some of us are!

 
Some of us are!


I can't read the blue print sticker on the electronic load... When was the equipment last calibrated? It's not a one and done thing... :p

But you made my actual point... quality and consistency of test equipment and methods are important. The cheap testers are not grounds upon which to claim a significant failure to meet spec.
 
The problem is the bullshit isn't walking. It's talking, and the money is buying it. The market is perpetuating it and will continue to do so on the false promises of non-conforming products sold way below market value.

Buy an EVE, Fortune, CALB, etc. cell from an authorized distributor? You have every right to jump up and down and scream bloody murder if capacity is missed by even a single mAh, and you should expect to be supported. Buying from sources that are selling known "cast-offs"? You just bought the bullshit.
Now we are back to where we started.
Its not good for the community.
 
It seems there are dramatically different expectations on these cells, particularly between the buyers and vendors.

For me, "new A grade cells" for these commodity cells means:
  • New appearance, but I was OK with minor cosmetic nicks or dings.
  • No structural flaws (dented corner, crushed in terminal, add more examples here)
  • No bulging (probably need to add some specifics based on spec dimensions)
  • QR codes in tact
  • Good threads (not crooked, not damaged threads)
  • test within ~3% of stated capacity (this one is tough, I think the burden is on the buyer to prove their test approach and it should be done at the individual cell level)
  • No extreme craziness with cell voltage behavior/performance (again, subjective, but any cell that is so out of whack that it can't perform with others between the knees). I can live with something running on the high or low end, but I've seen some reports of cells that are just unusable even if the capacity is in range.
  • Probably a couple other criteria I'm not thinking of.....
If I sent a list to a supplier before buying and asked them to agree to sending a replacement (or full refund of cell and shipping) for anything that didn't meet those requirements, do you think they would agree? Clearly, the buyers think a "new grade A" cell should meet those requirements and the vendors potion them that way, so why not include the detail and try to pin them down? I still think you'd have a problem with the capacity and voltage weirdness because it would be subject to testing process, but I see a lot of folks just arguing the physical damage stuff with vendors. If a supplier agreed up front to replace a cell that didn't meet the agreed upon standards, they might be less likely to slip a dented cell into that particular shipment (maybe).
 
I still think you'd have a problem with the capacity and voltage weirdness because it would be subject to testing process, but I see a lot of folks just arguing the physical damage stuff with vendors.
Agree, step 0 is a proper top balance.
As we have seen that is a a bit of a stumbling block.
 
Because it doesn't meet spec. 50-70%.
What part of the spec does it not meet? Is it gonna become bewitched by a poltergeist, throw off its case, and electrocute me in the middle of the night? Good questions to be asking the alibaba rep you’re dealing with, I suppose (though maybe not in such a jestful way).
 
What part of the spec does it not meet? Is it gonna become bewitched by a poltergeist, throw off its case, and electrocute me in the middle of the night? Good questions to be asking the alibaba rep you’re dealing with, I suppose (though maybe not in such a jestful way).

They probably can't answer the question.
 
Well, I guess I put myself in with the group that expects to receive what I am promised when I purchase something - doesn't matter if I am buying from manufacturer or re-seller. And I do think our response does shape the marketplace in the long run.

I think the best way to approach this is to ask plenty of questions of the seller to clarify exactly what you are getting and pay with the most protected option possible (probably Amex CC). If you didn't receive what you were promised, you use your leverage to have the seller make it right (CC chargeback, aliexpress dispute, putting a post on diysolarforum, etc).

There are always risks with any purchase and no guarantee you will be treated fairly - best to understand that going in and do what you can to mitigate that risk.
 
Considering how business is done, maybe should ask seller,
"What are the specifications you guarantee each cell will meet, where I will be given a refund (or can simply dispute/charge back) if they do not?"

If they would then respond "capacity 300 Ah +/-5%" setting expectation upfront, that should take care of future issues.

They haven't developed the thoroughly lawyered small print we get here: "on average, packages filled with amount shown, but your particular box of cereal unfortunately will contain less."
 
Considering how business is done, maybe should ask seller,
"What are the specifications you guarantee each cell will meet, where I will be given a refund (or can simply dispute/charge back) if they do not?"

If they would then respond "capacity 300 Ah +/-5%" setting expectation upfront, that should take care of future issues.

They haven't developed the thoroughly lawyered small print we get here: "on average, packages filled with amount shown, but your particular box of cereal unfortunately will contain less."
From what I've seen with different testing methods, I don't know how you are ever going to avoid painful disputes over performance with the vendor.

They physical stuff (dents, QR codes, bad threads, etc.) is easier to set some clear expectations that can be easily verified. It wouldn't solve everything, but it seems like might help address the physical damage and thread arguments.

When I got my cells through the group by with Michael, I tried to spell out what my expectations were around the cells. My list was far from perfect, but it was my best attempt to agree on expectations before I committed. I think I was a realist knowing these aren't really grade A new cells, but people see that in the advertising and want to believe it. If we don't try to set bounds around it as buyers, it's the wild west for the vendors and everything is subject to interpretation.
 
Last edited:
Considering how business is done, maybe should ask seller,
"What are the specifications you guarantee each cell will meet, where I will be given a refund (or can simply dispute/charge back) if they do not?"

If they would then respond "capacity 300 Ah +/-5%" setting expectation upfront, that should take care of future issues.

They haven't developed the thoroughly lawyered small print we get here: "on average, packages filled with amount shown, but your particular box of cereal unfortunately will contain less."
This ^
A deal is a deal.
 
I finally tested all four cells individually.
The first three cells I tested at 10a
The final cell I tested at 20a
My tester was set to cut off at 2.3v, which would mean about 2.5v at the cell.
My cables for cells 1 and 2 were a bit thinner than I'm comfortable with. My cables for cells 3 and 4 were quite good, usually around 0.05v drop from cell to terminals of the tester. So not entirely comparing all apples with apples TBH, but I had wanted to assemble better cables and see what difference it would make.

My photos are not always as the test completed so sometimes the cell has recovered a little bit of voltage. I also sometimes dropped the amps right at the end to see out of curiosity how long the test would go on for. Because the amps got quite low even if the test went on for a few minutes very little was added to the AH (to be expected).

Cell 1 - tried very low amps at end for a while which added about 1ah to the total
Cell 1.png

Cell 2 - usually hits low voltage first so surprised it's higher than cell 3
Cell 2.png

Cell 3, wasn't expecting it to lower than cell 2
Cell 3.png

Cell 4 was the best, but usually ends an assembled battery test at highest voltage. Wh are slightly lower than cell 3 though.
Cell 4.png
 
What type of cells are these?
Can you please post a picture of the top of a cell and if it has a label please post that also.
 
Is everyone using calibrated test equipment?
I can't speak for everyone, but my Kunkin has a calibration certificate from January 2021.
I know, old thread.

I'll say this much, if the vendor advertises "grade A" cells, then EVERY SINGLE CELL should meet or exceed their capacity rating.
That is what grade A means, it doesn't mean they touched it with a meter and recorded the voltage and IR just before shipping.
 
So what vendor would you recommend that is advertising something like 280 AH +- 5, and the average would be at 280 AH, not an average of -5% at 266 AH?

If no lithium vendors are doing this, would you be willing to switch back to FLA?
You buy grade A, you pay for grade A. She also sales bulk cells (that everyone else labels as grade A).

 
Back
Top