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Disappointing EVE 280K Results

Ce Ce said:
I wanted to share my recent (September 2022) disappointing experience buying prismatic cells to the forum. My plan was to buy a small group of prismatic cells (20 cells) and test them before committing to several larger purchases based on the results of the test.

I first did a bit of research on LiFePO4 cells and purchased some test equipment and went on a hunt for a supplier. To keep the total battery cost per Ah lower I planned to use cells in the 280-300 Ah range.

Based on nothing much more than comments in the forum, YouTube videos and email replies from some of the suppliers I decided to use Docan and worked with Jenny Wu. I will try to rank each part of the experience on a 1 to 10 scale.

  • Jenny Wu was very quick to respond to all my initial questions about the cells they have in stock. I could send Jenny Wu a question and within a few hours I would receive a reply along with the “are you ready to order” at the bottom of the email. A mark of a good sales person who is always trying to close that sale. Jenny seemed knowledgeable about their products and answered “most” of my questions about the cells very quickly. Often within a few hours.
  • After many emails describing the cell specifications, when they were manufactured, condition, capacity, shipping, and billing and what the supplier would do if there are problems with the cells (the replies to testing questions were rather vague) I decided on the EVE 280K cells. Then we discussed prices shipped from China vs shipped from Houston and I elected to pick them up at the Houston warehouse.
  • New 280 Ah cells and I can get them within a few days of ordering the cells. The price is a bit higher than other suppliers but other than that this seems like a reasonable deal. Due to a few of Jenny Wu’s answers being vague there are a few points off. (8/10)

  • The actual purchase of the cells went very smoothly. (10/10)

  • Setting up the pickup time was just a simple phone call and the people working at the warehouse were very friendly and helpful when I picked up the cells. (9/10)

  • The cells are packaged very well and it is doubtful even the most careless delivery driver could damage them in shipment. (10/10)

  • Once I had them back home a quick visual inspection of the of the cells showed them to be in very good condition. No bloating and with just a few visual blemishes. Not pristine but very good. (9/10)

  • In the next step the QR Codes were checked to validate the cells were made in December 2021. Some were and some in January 2022 and some in February 2022. Only a few of the cells were made on the same day and those were in different boxes. This was a concern since I expected new cells to all be from one batch so I ask Jenny Wu if it was normal to have so many different manufacturing dates and mentioned my concern. After numerous emails asking this question, I am still waiting for an answer. At this point I must assume Jenny Wu is not planning to answer.
  • My thought is that cells made in the same batch are going to match each other much better than cells from random batches. So for mismatched cells and poor customer service. (2/10)

  • The voltage and IR of the cells were checked. The voltage ranged from 3.2861-3.2951 V and the IR 0.18-0.20 mΩ. This seemed within specification from the EVE product specification sheet. (10/10)

  • The cells were charged to full capacity using the specifications from EVE Power Product Specifications for LF280K cells. They specify a charge rate of 0.5C at a voltage of 3.65 volts and a cut off change rate of 0.05 C. I could only charge at 40 Ah but I did use 3.65 volts as the voltage maximum and stopped charging at 0.05 C or 14Ah. The room temperature is 23-24C.
  • All of the cells required ~180 Ah to fully charge and were shipped at a 34-36% SOC. No dead cells and nothing with a high SOC and none of the cells showed any swelling when charged to 100% SOC so a (10/10).

  • The test conditions in the Eve Product Specifications were used as much as possible. Temperature 23-24C. After charging the cells to 3.65 V they sit for 60-90 minutes before the discharge test begins. A ZKETECH battery tester is used at 35Ah (0.125C) until the cell voltage is 2.8 V. At approximately one hour into the test the terminal temperatures are checked (23-24C). After the discharge test I either recharge to about 35% SOC or fully recharge if I plan to do a second test.
  • Since my early results were coming back low (263-275) I contacted Jenny Wu and other than one message claiming “The Battery Test Factory uses 30Ah” they never sent or said anything more. So, between the low test results and no response from the supplier. (1/10)
As a follow up to the 30Ah claim 3 cells were tested at 35Ah and then at 30Ah. The results of the test were all within a maximum 0.4 Ah of each other. I also retested 3 cells using a cut-off of 2.5V vs the 2.8V. Using 2.5V cut-off voltage resulted in 2.4- 2.8 extra Ah of capacity.

To be fair one cell did meet the 280Ah capacity test. It tested at 285.8Ah and a repeat test on that cell was nearly identical at 285.6Ah. Another interesting note is the few cells that were from the same batch all tested nearly identical capacities.

Overall… I am disappointed with the cells performance from Jenny Wu but more importantly I am disappointed in how the supplier handles problems. Before the cells were purchased we covered testing and performance. I did not expect a refund but did expect more than being ghosted by the supplier. So was I ripped off. Yes, I feel I was... My thought is even if it is a reasonable price if the supplier sells you 280Ah cells and you don’t get 280Ah cells then you were ripped off. It is just a question of how badly you were ripped off. As it is I can build a 263Ah battery from these cells and start looking for a new supplier.
Click to expand...
Not ripped off. You bought to a price. That is still a very good result. At the end of the day you aren't a commercial buyer and I'm a bit surprised you received the attention you received.
 
Ce Ce said:
Thank you for the welcome Bulldog225. Ripped off may seem like a strong word and I thought about if that phrase fit before I used it… However, I feel when you pay for something and then do not receive what you paid for you were ripped off. The rest is just the degree you were ripped off. I agree it is not as bad as the person that tested their cells at 89% or as good as the person that tested them at 98% but we were all ripped off just to different degrees.

Now the company that ripped you off can mitigate the situation. Offering a discount on your next order of cells for example. Then you feel like you got what you paid for even if you are disappointed in the results. In this case the suppliers represenitive, Jenny Wu, decided to ignore even simple emails questions like “ is it normal to buy 20 cells and have 15 different manufacturing dates”. So ripped off seems to fit.
Click to expand...

De minimis non curat lex​

 
Ampster said:
I am not sure that is a good assumption. I do not know how big the batches are or how many cells are produced per day. I have heard that some where after the process of forming the cells that they are tested and binned according to capacity and other factors. That is where the matching takes place.
Click to expand...
I disagree. This is a red flag you are getting GRAY market cells. Its not a terrible thing for us hobby folks but would be a disaster at retail market level.

Its a science of tracking. If your Lithium provider is sending cells from different MONTHS this tells me they were grouped AFTER a previous sale/return/reject etc.

Worked in a Lithium Ion battery plant for years.
LOT Numbers are created based on--just to name a few:
1. Batches of electrode (Anode & Cathode)
2. Date of Formation (Initial chare/Discharge)
3. Any process or component change or even shift change

LOTS are graded by performance (A-B-C-D-E-F-G-RECYCLE) FYI-- 18650 are different as grade D/E are usually hitting the nominal capacity on the datasheet. A&B are serious overachievers.

These are done to track ANY change or quality issue for recalls/warranty etc. Make no mistake this is a BIG deal. Any BIG buyer of cells will require shipments all be tracked by PO/ LOT and cell grade. Imagine DELL or Tesla being informed by Panasonic they have to recall 18650 batch for safety.
 
DENWA said:
This is a red flag you are getting GRAY market cells.
Click to expand...
I have already assumed that these cells are grey market cells. How or why they are not the same date doesn't matter to me either. I also suspect they may have traveled through several places on their way to the vendors we actually purchase from them. Ten years ago I bought 72 Winston 10O Amp cells from a US based supplier for an EV conversion. They may have been Grade A but they also cost $300 per kWh. I am happy with my grey market cells that cost $125 per kWh. I bought four spares in case some were bad The spares are in a 12 volt pack I use to power my my relatives refrigerator when their power goes out.
 
DENWA said:
Any BIG buyer of cells will require shipments all be tracked by PO/ LOT and cell grade. Imagine DELL or Tesla being informed by Panasonic they have to recall 18650 batch for safety.
Click to expand...
I am not a BIG buyer and I don't have to imagine, two family members were affected by the recall of cars with cells made and sold by LG Chem. Stuff happens in life and there are no guarantees. So far I have been lucky but I do implement some risk management strategies from time to time.
 
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DENWA said:
I disagree. This is a red flag you are getting GRAY market cells. Its not a terrible thing for us hobby folks but would be a disaster at retail market level.

Its a science of tracking. If your Lithium provider is sending cells from different MONTHS this tells me they were grouped AFTER a previous sale/return/reject etc.

Worked in a Lithium Ion battery plant for years.
LOT Numbers are created based on--just to name a few:
1. Batches of electrode (Anode & Cathode)
2. Date of Formation (Initial chare/Discharge)
3. Any process or component change or even shift change

LOTS are graded by performance (A-B-C-D-E-F-G-RECYCLE) FYI-- 18650 are different as grade D/E are usually hitting the nominal capacity on the datasheet. A&B are serious overachievers.

These are done to track ANY change or quality issue for recalls/warranty etc. Make no mistake this is a BIG deal. Any BIG buyer of cells will require shipments all be tracked by PO/ LOT and cell grade. Imagine DELL or Tesla being informed by Panasonic they have to recall 18650 batch for safety.
Click to expand...

Another BB consumer. Good luck and be well.
"Gray market", 'aftermarket', call 'em whatever you want - they're CHEAP. Enjoy or not, nobody is being 'ripped off'. This thread is a joke...I'm out. ?
 
Browneye said:
Another BB consumer. Good luck and be well.
"Gray market", 'aftermarket', call 'em whatever you want - they're CHEAP. Enjoy or not, nobody is being 'ripped off'. This thread is a joke...I'm out. ?
Click to expand...
No one got ripped off.
No need to name call.
If facts hurt your feelings please feel free to go.
 
Browneye said:
Another BB consumer. Good luck and be well.
"Gray market", 'aftermarket', call 'em whatever you want - they're CHEAP. Enjoy or not, nobody is being 'ripped off'. This thread is a joke...I'm out. ?
Click to expand...
You agree on something.
You pay the price in full.
You receive a portion of what has been agreed.
Until new agreement is achieved, someone should be pi$$ed...
 
SolaroSsaurius said:
You agree on something.
You pay the price in full.
You receive a portion of what has been agreed.
Until new agreement is achieved, someone should be pi$$ed..
Click to expand...
Yes that is how it works in the USA. When buying offshore one has to adjust expectations, otherwise you will be disappointed. You call it pissed. I call it not understanding what you are dealing with. If you want Automotive grade matched cells spend the extra dollars and get precisely what you bargained for. As mentioned earlier, these are grey market cells.
 
Last edited:
Before ordering cells from Docan I'm getting measurement results with IR and capacity. Cell capacity is stated to be more than the offered one. I.e. 280Ah cell is sold as 280Ah cell with tested capacity close to 300Ah (my case). Based on these I would expect the cells to exceed the 280Ah capacity if they were advertised to do so before making the purchase. And if they don't - this is a rip-off.

I'm not going to test the capacity of the cells before assembling the pack. As long as IR is in norms and none of them has severe capacity degradation I'll be fine with the battery. If cells are batched then this shouldn't be an issue.
 
I think there is an issue with 280K made in December 2021 - January 2022 where they were low on capacity. All grades affected.
 
sunshine_eggo said:
This is an expectation issue, not a cell/supplier issue. You just got 95% capacity cells for 50% the price.
Click to expand...
You're absolutely right, it is an expectation issue.

What I personally find dumb as shit is that if Docan just straight up told us to expect x% less capacity, and explained that the reason they are slightly lower capacity is because they are new, but unused cells that didn't meet the EV spec - but that is reflected by their lower price, I would be fine with that (and clearly so would many others here, because most posters here acknowledge that this is in fact what we are buying).

So yes, it's an expectation issue, but the core of it is that Docan is taking no action to set the right expectation that a customer should have, then just ignoring customers when they inquire. It's bullshit.

Anyone that comes to this forum and reads the vendor reviews, probably has reasonable expectations, but it should really be on the vendor to set the expectations properly to avoid any misunderstandings.

In the end I would rather deal with a vendor who is at least honest about what they are selling (saying this as someone who has bought from Docan, but with the right expectations).
 
Out of curiosity - what was the price of the 280Ah EVE cells listed in the first post?
 
No mention of bloating? I ordered 32- 280 ah cells from Docan that I found on Will Prowse's online list. I didn't use a sales person/rep my first mistake maybe? I guess it doesn't make a difference now, I Just added to cart and checked out. I'm feelin kind of dumb now, the majority of them are bloated, I can't say that any of them are perfectly flat, at least the sides don't touch some more than others. I'm nervous about capacity testing them now, hoping for the best expecting less. By the way when I emailed Docan about the bloating and sent photos, they responded with " We checked with the factory and they said to cycle the battery 5 times and it should correct it" I'm not buying it! How serious is this bloated cell issue, should I even worry about it?
 
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