EVE 280 Ah from Shenzen Basen are not "brand new" as advertised

[Ampster]

A very disappointing result.

As others have said, I am happy with cells that come within 3% of capacity. Voltage differences at the bottom are only confirmation that these cells have not been matched. I did not expect to get matched cells for the price I paid. I could have paid a lot more for matched cells but chose to save the money and manage my expectations. In September I purchased 8 of these cells from Emily and they have behaved consitently with 40 others that I purchased from two other vendors.

 

[TdKo]

As others have said, I am happy with cells that come within 3% of capacity. Voltage differences at the bottom are only confirmation that these cells have not been matched. I did not expect to get matched cells for the price I paid. I could have paid a lot more for matched cells but chose to save the money and manage my expectations.

These offer the cells as matched Grade A; then they should deliver it. The expectations were created by the offer, which were not met.

 

[upnorthandpersonal]

These offer the cells as matched Grade A; then they should deliver it. The expectations were created by the offer, which were not met.

Grade A = 'never used', Matched = 'we measured the voltage and IR and they're the same'. No one, except maybe for Amy at this time, sells matched cells in the meaning of capacity and IR matched. This has been discussed in on these forums since we started buying these.
What I would do is enjoy the 3.3kWh of storage at extremely low cost, maybe get a replacement/50% discount on that one cell, and sit back and relax knowing that getting 3.3kWh from any other place will cost you verdammt viel mehr.

 

[TdKo]

Grade A = 'never used', Matched = 'we measured the voltage and IR and they're the same'. No one, except maybe for Amy at this time, sells matched cells in the meaning of capacity and IR matched. This has been discussed in on these forums since we started buying these.
What I would do is enjoy the 3.3kWh of storage at extremely low cost, maybe get a replacement/50% discount on that one cell, and sit back and relax knowing that getting 3.3kWh from any other place will cost you verdammt viel mehr.

Ja, Du hast Recht ??

 

[fafrd]

Grade A = 'never used', Matched = 'we measured the voltage and IR and they're the same'. No one, except maybe for Amy at this time, sells matched cells in the meaning of capacity and IR matched. This has been discussed in on these forums since we started buying these.
What I would do is enjoy the 3.3kWh of storage at extremely low cost, maybe get a replacement/50% discount on that one cell, and sit back and relax knowing that getting 3.3kWh from any other place will cost you verdammt viel mehr.

Excuse me, you think a cell delivering 277.1Ah / 99% of advertised capacity is worth a replacement or a 50% discount???

1% would be more appropriate.

Buying these heavily-discounted grey-market cells is the equivalent of picking up batteries at a flea market.

Anyone wanting guarantees should understand guarantees costs money and should purchase directly from EVE, who manufactures these cells to start with).

 

[Gazoo]

Ja, Du hast Recht ??

So they have agreed to compensate you a total of $69.60. Between that and your capacity test you should be happy. My EVE cells didn't have any dents and my lowest cell is capable of 272ah's. I am happy with that. That is equal to 97% capacity.

You might also consider changing the rating you left for Emily? Of course that's up to you.

 

[upnorthandpersonal]

Excuse me, you think a cell delivering 277.1Ah / 99% of advertised capacity is worth a replacement or a 50% discount???

I don't, but the seller offered it.

 

[fafrd]

I don't, but the seller offered it.

Actually, they offered ~50% compensation primarily because of an oxidized terminal as well as some for scratches & patches.

50% compensation for a cell delivering 1% less capacity than advertised would be ridiculous...

 

[Ampster]

These offer the cells as matched Grade A; then they should deliver it. The expectations were created by the offer, which were not met.

Definitions vary on what the term "matched" means. I agree that the definition used by @upnorthandpersonal is the the one used by my vendor in this grey market. Furthermore additional fuzzines is added or something is usually lost in translation between cultures.

 

[fafrd]

Definitions vary on what the term "matched" means. I agree that the definition used by @upnorthandpersonal is the the one used by my vendor in this grey market. Furthermore additional fuzzines is added or something is usually lost in translation between cultures.

These battery cell resellers/trading companies test cells for Internal Resistance and voltage and ‘match’ them on that basis (at most).

None of them (directly) test and match cell capacity, let alone characterize and match full charge & discharge curves.

In sufficient quantities, the manufacturers like EVE can do true capacity/curve matching but so far, we know of only one reseller who appears to have reached an agreement with EVE to deliver cells directly (rather than through a broker) and including cell-by-cell capacity test data.

 

[Supervstech]

Actually, they offered ~50% compensation primarily because of an oxidized terminal as well as some for scratches & patches.

50% compensation for a cell delivering 1% less capacity than advertised would be ridiculous...

Keep in mind that TRUE grade A cells for the first few dozen or so cycles, average a bit higher than rated capacity. So having one measure ANY under rating is cause for concern... what will they be outputting in a hundred cycles? 5% low? 10?
Perhaps these cells are new old stock, showing heavy age self discharge... I’m not sure how this chemistry rates after sitting unused on a shelf for several years...
does anyone?

 

[curiouscarbon]

Keep in mind that TRUE grade A cells for the first few dozen or so cycles, average a bit higher than rated capacity. So having one measure ANY under rating is cause for concern... what will they be outputting in a hundred cycles? 5% low? 10?
Perhaps these cells are new old stock, showing heavy age self discharge... I’m not sure how this chemistry rates after sitting unused on a shelf for several years...
does anyone?

The temperature of storage is the main parameter to me. Calendar aging rate

It’s so important that I’m working towards 24/7 temperature regulation of my cells to like 25C

 

[Gone]

According to this author, storage at 35C results in minimal capacity loss.
Degradation due to usage (rather then storage) may be a different beast, with lower temperatures better for discharge than charge.

Are capacity loss and degradation essentially the same thing? I don't know.

 

[curiouscarbon]

Thank you @Ale. I’m still learning about the temperature aging with LFP and those sources are greatly appreciated.

 

[Gone]

We're all still learning, which is why this forum is so great!

Someone once posted information (from EVE I think) that at a certain temperature there was zero degradation.
I think it was an early discussion focused on fixtures and the value of compression, but unfortunately I can't find it.

 

[Gazoo]

We're all still learning, which is why this forum is so great!

Someone once posted information (from EVE I think) that at a certain temperature there was zero degradation.
I think it was an early discussion focused on fixtures and the value of compression, but unfortunately I can't find it.

You can find the spec sheets for the cells in the resources section of the forum. EVE does recommend 0℃～35℃ for long term storage. I tend to go by the spec sheets. I learn something new here every day.

 

[curiouscarbon]

Ok, so what's becoming apparent to me is that there's at least three factors:

Degradation from:
Temperature vs charging
Temperature vs discharging
Temperature vs storage

Those graphs are great


Multiple temperature trials below freezing~?

 

[Gone]

Yeah, I downloaded the spec sheets for EVE and Lishen straight to my desktop long ago.

 

[curiouscarbon]

According to this author, storage at 35C results in minimal capacity loss.
Degradation due to usage (rather then storage) may be a different beast, with lower temperatures better for discharge than charge.

Are capacity loss and degradation essentially the same thing? I don't know.

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paper added

 

[HRTKD]

I'm not too worried about the degradation. If I get "only" 3500 cycles out of my eight cells, that's over nine years. I will have moved on from this trailer long before that, or the technology will have come up with something that will compel me to upgrade early.

 

[Gone]

Copy that. Retired with time on my hands, it's just an interesting topic (like compression).

 

[LaFabrik]

we know of only one reseller who appears to have reached an agreement with EVE to deliver cells directly (rather than through a broker) and including cell-by-cell capacity test data.

Hi Fafrd, can you tell which is this reseller please ? name ? thanks a lot

 

[fafrd]

Hi Fafrd, can you tell which is this reseller please ? name ? thanks a lot

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[Primeral]

How strange. I ordered from the same vendor a couple of days after the OP's order on January 8, but they took over 2 months for them to pass customs.

Mine appear to be brand new Grade A cells with holographic QR stickers and all 16 were perfectly matched. It's odd to have a completely different experience and our orders were only a few days apart

 

[TdKo]

Shenzen Basen bamboozle more and more customers:

WARNING. Do not buy from Shenzhen Basen. Alex Chen.

I ordered 4 x 280ah lifepo4 cells on 10th November 2020 and I have still not received them. I have asked for a refund from the seller with no response. The past 3 weeks I have gone through the Alibaba refund process only to be told they will not give a refund even though they know from the...

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