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Arguing with Aliexpress vendor. Maybe I’m wrong?

TL2021

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Oct 14, 2020
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I have been having a back and forth with this vendor about two of the 16 cells they sold me that are weaker than the others. When charging they reach 100% faster, and also reach 0% faster when discharging. All 16 were top balanced to 3.65v. According to the BMS, I only pulled 272 out of 280ah because the two cells reached the disconnect point. They told me to use an active balancer. I said I shouldn’t have to if these are new matched grade A cells.

First they tried to say that it was the BMS’s and my fault because I charged above 3.35v and the disconnect voltage was set at 2.2v(default setting) instead of 2.5v. I said that doesn’t make any sense as to why charging to charging to 100% and discharging deeper means less capacity. Then they went on about loose connections and such.

So they are really digging their heels into there is nothing wrong with the cells they sold. I guessed it was a capacity issue so now they are wanting me to test just these two cells individually. Is that entirely necessary? If they were properly balanced and connected, why would additional testing be needed?
 

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That's actually not a bad capacity from batteries bought from aliexpress. You should feel lucky. Your not going to get any kind of refund from them, aliexpress allways sides with the seller. Or they will have you send them back and once received they will send you a replacement. The price of sending them cost far more than what the battery is worth. Most of us on the forum no not to buy batteries from aliexpress.
 
You can just take a pragmatic approach claiming the 272Ah out of 280Ah come from the 2 defective cells and from there claim a proportional refund. This because the difference is not very big; I would personally test the two cells individually only If the difference was big to know If the missing capacity is from the whole pack or only from the two cells; and actually the main motivation to do that would be for my understanding. I still believe in no matter which conditions If a pack provides less than stated, it is the seller's responsibility.
 
That's actually not a bad capacity from batteries bought from aliexpress. You should feel lucky. Your not going to get any kind of refund from them, aliexpress allways sides with the seller. Or they will have you send them back and once received they will send you a replacement. The price of sending them cost far more than what the battery is worth. Most of us on the forum no not to buy batteries from aliexpress.
Depends on how you ask the refund. In these situations I normally follow this method: 272Ah/280Ah = 0,97; therefore If price is 500 eur. (1-0,97) = 15 eur. refund and I normally add a little plus for the inconvenience; so maybe 30 eur. total.
 
After jumping through all there hoops and spending 2 weeks of back and fourth and then have them say we need you to video your capacity test and send it to them its just not worth 8ah or at the most 30$.
 
After jumping through all there hoops and spending 2 weeks of back and fourth and then have them say we need you to video your capacity test and send it to them its just not worth 8ah or at the most 30$.
Then they say that your tester isn't calibrated, and you can't upload a video that long. ?
 
2.2 volts is a bit low but they all should react the same. If you have any offer for refund.... take it.
If the two cells are going to significantly affect the battery you may as well get replacements from a different vendor.

Nothing wrong with mentioning the seller. Be sure to post a nice review with the facts only, not your frustration.
 
I only pulled 272 out of 280ah
You are getting over 97% of capacity from what is possibly a cheap or uncalibrated tester. And even then you'd need several identical tests to be statistically significant.

You are miles ahead of almost everybody who has made the Aliexpress gamble.

Even if they offered to pay to ship these back and send you two new cells, what are the chances they will be better than 97%?

Does your battery system not work for your use case if its only delivering 97%?
 
Who's the vendor? Buying cells off of Aliexpress goes wrong more often that it goes right...
Oye store. I’ve purchased from them last year, and the cells were great. This time around I only received half my order because a different shipment of batteries exploded. And now they are giving me the run around on this.
 
You are getting over 97% of capacity from what is possibly a cheap or uncalibrated tester. And even then you'd need several identical tests to be statistically significant.

You are miles ahead of almost everybody who has made the Aliexpress gamble.

Even if they offered to pay to ship these back and send you two new cells, what are the chances they will be better than 97%?

Does your battery system not work for your use case if its only delivering 97%?
My fear is that something is wrong with the cells and will fail in the near future, and I will have to get two new cells anyway.
 
My fear is that something is wrong with the cells and will fail in the near future,
Have you seen lower capacity cells show signs of "something being wrong" or showing signs of failure? I'd like to learn from your experience if so.

I have not seen ANY tail off of capacity from any of my cells (over 60 in use in nearly a dozen batteries) over the period of a couple years. Personally i think the worry is unnecessary but we all have our comfort levels and belief systems.

Looking back at your OP and the pictures showing the cell voltages after a complete discharge cycle. Those numbers look GREAT. I'd be giddy to get that kind of dispersion at the very bottom of the SoC range (especially if top balanced).

If you think your cells should be better, i'd recheck the connection to cell 6 and redo the capacity test though i cannot imagine a set of 16 cells being better than what you are showing. Maybe my standards and expectations are low?
 
My fear is that something is wrong with the cells and will fail in the near future, and I will have to get two new cells anyway.
One thing i just thought of, and maybe its a little bit optimistic on how things work in the real world...
Can you make a deal, in writing with specific circumstances and actions, for a few months or whatever time period you are comfortable with, with the seller, in case the 2 cells do go south (my some specific amount)?

OTOH, I can see why the seller would hesitate because people do kill cells by making mistakes or continually stress testing them for various reasons (mostly from what i've seen, is to feel good about your purchase).

I'm done, hopefully this was not too soapbox-like... sorry if so.
 
Have you seen lower capacity cells show signs of "something being wrong" or showing signs of failure? I'd like to learn from your experience if so.

I have not seen ANY tail off of capacity from any of my cells (over 60 in use in nearly a dozen batteries) over the period of a couple years. Personally i think the worry is unnecessary but we all have our comfort levels and belief systems.

Looking back at your OP and the pictures showing the cell voltages after a complete discharge cycle. Those numbers look GREAT. I'd be giddy to get that kind of dispersion at the very bottom of the SoC range (especially if top balanced).

If you think your cells should be better, i'd recheck the connection to cell 6 and redo the capacity test though i cannot imagine a set of 16 cells being better than what you are showing. Maybe my standards and expectations are low?
I only guessed and said capacity. I don’t know enough to diagnosis why two cells out of a batch of 16 280ah cells seemingly have lower capacity than the others. With their claim of testing and matching cells before shipping, I find it hard that they shipped me 272ah cells by accident.
I’ll just let it go. To others‘ point, they probably wouldn’t ship me two new batteries which is what I was asking.
 
I’ll just let it go.
You have very good cells. If the numbers all came in at 280Ah you would never tell the difference from the 272Ah.
3% on 2 cells is probably the smallest of half a dozen losses in your system.

Enjoy your battery. You've done pretty well and should be ecstatic.
 
SCAM!!!! I bought 64 'Brand new 200AH' cells tested them and only got 117-133AH. Watever you do do not buy from this company. They only sell used and substandard cells. Don't fall for their cheap prices there is a reason for it. They insist the batteries are new and refuse to resolve the issue. They have no interest helping their customers. Please see my test results below.
 

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