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New 280K cells not pulling full capacity

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dimsi

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Feb 1, 2022
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Hey all, newbie here. Purchased my first 8 EVE LF280K cells from US stock a few weeks back and they aren't pulling full capacity. Seller says that is normal for 2022 stock.

I patiently did a top balance and a capacity test from 3.65 to 2.5v. Got about 268ah with a load of .5C. I've now also tested some of the cells individually at less then 0.1C load and I'm yielding 272-273ah. The seller claims EVE cells produced in 2022 are all 270-280ah, and that's expected.

I thought the cells being new have to pull at least 280 the first tests., so I'm not sure how to feel about this. Am I getting some leftovers from a warehouse sold as new, or is this the same across the board?

Checked the cell manufacture dates, they range from Dec '21 to Jan '22.
 
Paid $149 per cell, shipping included - directly from Docan's website. They are the older type with welded studs.
 
Hook them up and use them. They are too heavy and expensive to ship. I have two out of 10ea 16S 280aH batteries that I'm not that proud of, paid more or as much for them?. I just don't charge them above 55.4V. I don't think you're gonna get full capacity out of any of these at a .5 C. My batteries rarely see more than 40 A in or out, let alone 140A. if so, you need more batteries/BMS for longer life/redundancy.
 
How are you getting a 0.5 C(A) load? There are a lot of opportunities for measurement error with that amount of current.

If you are using a sinewave inverter to load battery the current profile is a near sinewave at twice the inverter AC frequency. The peak current of the sinewave current profile will be about twice the average DC current and minimum of sinewave current profile will be close to zero current. The average will be DC current reading. The high peak current will create more losses in battery resulting in a lower net AH capacity, typically about 2% to 3% less with a 0.5 C(A) average current load.

The current measuring device also has to be able to do a good averaging job of the 2x AC line frequency ripple current.
 
Also remember that "new" does not mean "meets spec". EVE sells cells that do not meet spec to other distributors. They are still "new" but most likely would never pull 280Ah.
 
RCinFLA said:
How are you getting a 0.5 C(A) load? There are a lot of opportunities for measurement error with that amount of current.

If you are using a sinewave inverter to load battery the current profile is a near sinewave at twice the inverter AC frequency. The peak current of the sinewave current profile will be about twice the average DC current and minimum of sinewave current profile will be close to zero current. The average will be DC current reading. The high peak current will create more losses in battery resulting in a lower net AH capacity, typically about 2% to 3% less with a 0.5 C(A) average current load.

The current measuring device also has to be able to do a good averaging job of the 2x AC line frequency ripple current.
Click to expand...
Any inverter worth owning will have capacitors large enough there is negligible DC ripple.

Also if the OP is using the same gear in testing as they will use in the permanent installation, still seems legit set up, all that’s arguing is the numbers produced from east test.

I will say .5c is mighty impressive for load of 280ah cells.

I’d live with the .1c results if you’re concerned about AH numbers. Any ESS should be designed/sized for lowest C rating as possible.

It’s been know for quite some time Docan sells cells that are good value, not EV grade. I have 8 230ah cells and no complaints, never tested them but happy with how they stay balanced.
 
Last edited:
Sounds like Docan provided those numbers.

The OP could have asked what those numbers are before purchasing so they wouldn’t be surprised with results.
 
Same experience with Docan. I got as low as 267ah and couple of bulged cells.
 
740GLE said:
Sounds like Docan provided those numbers.

The OP could have asked what those numbers are before purchasing so they wouldn’t be surprised with results.
Click to expand...
I did asked and Jenny Wu even confirmed that I'd get more than 280ah
 
dimsi said:
Hey all, newbie here. Purchased my first 8 EVE LF280K cells from US stock a few weeks back and they aren't pulling full capacity. Seller says that is normal for 2022 stock.

I patiently did a top balance and a capacity test from 3.65 to 2.5v. Got about 268ah with a load of .5C. I've now also tested some of the cells individually at less then 0.1C load and I'm yielding 272-273ah. The seller claims EVE cells produced in 2022 are all 270-280ah, and that's expected.

I thought the cells being new have to pull at least 280 the first tests., so I'm not sure how to feel about this. Am I getting some leftovers from a warehouse sold as new, or is this the same across the board?

Checked the cell manufacture dates, they range from Dec '21 to Jan '22.
Click to expand...
I think these 280K cells EVE has made are some duds, there is a rumor going around that they had a large order get cancelled when some car factory cancelled the order from due to quality issues, and then EVE dumped them onto the market. I have seen this come too many times to consider it to be a co-incidence.

But these cells were made between November 2021 to January 2022. I finally ordered a fan tester and tested my Genuine Matched & Batched Luyuan Cells I got 278.4 AH and 899 Watt hour on 1 and 277 and 897 Watt hour on another. I paid $193 shipped per cell with taxes shipped To Dallas, TX.

I'm not sure what to think, But I can say the cells charge evenly and discharge evenly. They were slightly bulged vs the 280N I have from Basen (these cells are junk btw, they always jump up during charging and are the first one to plummet to 0 when discharging, its literally impossible to charge them...)

I think this 280K is itself a defective design, I even chatted with Lampard Li on EVE gave them the QR code and he said it was fine. I think EVE is hiding something.

I'm not blaming Amy Wan, but just this Chinese way of doing business it flows from the top. Credit card charge back is no longer an option as its been over 6 months, my spread sheet said the cells were supposed to be 284 AH on average.


I know I'm not the only one who has 280K made in this period Nov 2021 - Jan 2022 that has some funk capacity results, even the supposed grade A cells...
 
Alkaline said:
I think this 280K is itself a defective design,
Click to expand...
How does it differ from any of the other cell designs out there? Rectangular box with two terminals on top and jelly roll of anode and cathode inside? My LF280' have functioned well for two years..I am sure you can find automotive grade cells for over $250 per kWh.
 
Ampster said:
Yes, welcome to the world of international trade where 280 could mean 270-280. You can decide to be angry or figure you got a reasonable deal. Some sellers of EVE cells carry a higher quality and better matched set of cells. Who was the vendor and how much did you pay deliver to your door?
Click to expand...
This thread makes me wonder how many of the commonly used FLA would have tested at rated capacity back when they were the only game in town? I bet very few would have. Lab quality (or near) capacity meters weren't available back then to DIYer's.
 
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