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Disappointing EVE 280K Results

Ce Ce

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Sep 14, 2022
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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.
 
Can you post your results like screenshots he ZKE has a graph right? What were the WATT hour for each test?

I will tell, you I have some grade A genuine matched and batched luyuan cells they are barely getting 280AH usually 276-278, but they are all over 900 WH according to my little amazon tester.

I keep hearing that EVE had a major customer cancel an order of 280K because of quality issues and these are now flooding the market. People that have 280K made in June of 2021 and earlier have had good results.

Post whatever details you can.
 
Can you post your results like screenshots he ZKE has a graph right? What were the WATT hour for each test?

I will tell, you I have some grade A genuine matched and batched luyuan cells they are barely getting 280AH usually 276-278, but they are all over 900 WH according to my little amazon tester.

I keep hearing that EVE had a major customer cancel an order of 280K because of quality issues and these are now flooding the market. People that have 280K made in June of 2021 and earlier have had good results.

Post whatever details you can.
Alkaline, thank you for the reply. Reading the Testing Procedure in Section 4 and Electrical Performance in Section 5 of the EVE Power Co., Ltd Product Specification there is no mention of cells meeting a watt requirement. Nor are there any test procedures specific to measuring a cells capacity in watts. However, I did record the watt values from each test. All the cells except for one failed to meet the capacity in watts as well.

4. Test conditions
4.1 Test environment conditions Temperature:25±2℃ Relative humidity (RH): 15%~85% Atmospheric condition:86KPa~106KPa
4.2 Standard Charge The standard charge means charging the cell with charge current 0.5C(A) and constant voltage 3.65V at (25±2)℃, 0.05C cutoff.
4.3 Standard Discharge The standard discharge means discharging the cell with discharge current 0.5C(A)and cutoff voltage 2.5V at (25±2) ℃.
Performance of the cells is discussed in Section 5

5.1 Electrical performance
Rate discharge performance at 25℃
Discharge capacity/nominal capacity×100% A)0.5C (A) ≥100% B)1.0C (A) ≥98%
After standard charge and 1h rest, discharge to 2.5V cutoff with the current of 0.5 C (A), 1.0C (A), respectively. If the discharge capacity fails to meet the technical requirements, this test is allowed to be repeated three times.

The data for 3 of the cells is listed below. If anything, the lower discharge rate should allow the cells to meet their rated capacity easier.

Cell 006 Room Temp 23.5C (my one good cell)
Chg/Dis --------------- Discharge
Ah ---------------------- 285.20
Watts ------------------ 926.31
IR mΩ ------------------ 0.18
Dis/Crg Rate Ah------ 35
Manufacture Date--- Jan 20, 2022

Cell 012 Room Temp 23.5C (Three test on the same cell)
Chg/Dis --------------- Discharge
Ah ---------------------- 265.20
Watts ------------------ 860.88
IR mΩ ------------------ 0.19
Dis/Crg Rate Ah-------- 30
Manufacture Date--- Dec 24, 2021

Chg/Dis --------------- Charge
Ah ---------------------- 266.10
Watts ------------------ No Measured
IR mΩ ------------------ 0.19
Dis/Crg Rate Ah------- 40
Manufacture Date--- Dec 24, 2021

Chg/Dis --------------- Discharge
Ah ---------------------- 265.70
Watts ------------------ 861.88
IR mΩ ------------------ 0.19
Dis/Crg Rate Ah------- 40
Manufacture Date--- Dec 24, 2021

Cell 016 Room Temp 23.5C (my one good cell)
Chg/Dis --------------- Discharge
Ah ---------------------- 266.50
Watts ------------------ 862.02
IR mΩ ------------------ 0.20
Dis/Crg Rate Ah------ 35
Manufacture Date--- Dec 27, 2021
 
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My thought is that cells made in the same batch are going to match each other much better than cells from random batches.
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.
 
Alkaline, thank you for the reply. Reading the Testing Procedure in Section 4 and Electrical Performance in Section 5 of the EVE Power Co., Ltd Product Specification there is no mention of cells meeting a watt requirement. Nor are there any test procedures specific to measuring a cells capacity in watts. However, I did record the watt values from each test. All the cells except for one failed to meet the capacity in watts as well.

4. Test conditions
4.1 Test environment conditions Temperature:25±2℃ Relative humidity (RH): 15%~85% Atmospheric condition:86KPa~106KPa
4.2 Standard Charge The standard charge means charging the cell with charge current 0.5C(A) and constant voltage 3.65V at (25±2)℃, 0.05C cutoff.
4.3 Standard Discharge The standard discharge means discharging the cell with discharge current 0.5C(A)and cutoff voltage 2.5V at (25±2) ℃.
Performance of the cells is discussed in Section 5

5.1 Electrical performance
Rate discharge performance at 25℃
Discharge capacity/nominal capacity×100% A)0.5C (A) ≥100% B)1.0C (A) ≥98%
After standard charge and 1h rest, discharge to 2.5V cutoff with the current of 0.5 C (A), 1.0C (A), respectively. If the discharge capacity fails to meet the technical requirements, this test is allowed to be repeated three times.

The data for 3 of the cells is listed below. If anything, the lower discharge rate should allow the cells to meet their rated capacity easier.

Cell 006 Room Temp 23.5C (my one good cell)

Chg/Dis Ah Watts IR Dis/Crg Rate Manufacture Date
Discharge 285.50 926.31 0.18 35Amps Jan 20, 2022

Cell 012 Room Temp 23.5C

Chg/Dis Ah Watts IR Dis/Crg Rate Manufacture Date
Discharge 265.20 860.88 0.19 30 Amps Dec 24, 2021
Charge 266.10 40 Amps
Discharge 265.70 861.88 0.19 40 Amps

Cell 016 Room Temp 23.5C

Chg/Dis Ah Watts IR Dis/Crg Rate Manufacture Date
Discharge 266.50 862.02 0.20 35 Amps Dec 27, 2021

Ok well there is clearly a difference then, I think your cells maybe some issue because the worst cell I have is 276 AH but has 899 WH. But looking at your tests you are below 896WH so something is not right with these.

However, I also don't think what I have is all that great either, if you have a cell that is doing 285.50 and 926.31 that is better than any of Matched & batched cells, I paid close to $190/cell shipped via alibaba with taxes and credit card fees.

My friend has the same 280K from Luyuan and he tested with the same amazon tester I have, he got:

289 AH 945 WH manufacturer date was August 18th 2021 consistently with all 8 of his cells. I can't even break 280. I think even grade B pre December 2021 are all testing well but after December 2021 they are not good.

Then there is this rumor that some big car manufacturer cancelled a big eve order that was mostly 280K and these were then dumped onto the market being sold as grade A by EVE when they are not. If this is true then the whole market is rotten from manufacturers to sellers, but not surprising its China after all.
 
This is the tester I am using btw:


It has v-sense cables port I'm using 24 awg wire for the v-sense and 10 guage for the main.

Hobotech uses this same tester and has had good results with it, may be not as accurate as the ZKE, but I still should break 280AH regardless of the WH IMHO, however I'm consistently short 1-3 AH...

I don't have a problem with the cells, unlike my basen or xuba cells there are NO runners or Volt trigger happy cells so they perform fine, I just don't like it that they are below what the should be.

Perhaps this as good as it gets with DIY...
 
About 94% good? Sorry it isn’t quite there. Ripped off seems a little strong to me.

Welcome to the forum.
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.
 
This is the tester I am using btw:


It has v-sense cables port I'm using 24 awg wire for the v-sense and 10 guage for the main.

Hobotech uses this same tester and has had good results with it, may be not as accurate as the ZKE, but I still should break 280AH regardless of the WH IMHO, however I'm consistently short 1-3 AH...

I don't have a problem with the cells, unlike my basen or xuba cells there are NO runners or Volt trigger happy cells so they perform fine, I just don't like it that they are below what the should be.

Perhaps this as good as it gets with DIY...
Alkaline thanks for the additional comments. The Vastarry type tester is pretty nice since you’re not limited to 5V like you are with the ZKETECH. You can test a battery in addition to testing cells which is quite useful.

Accuracy of test equipment is always something that can be questioned especially with affordable equipment. So, I have focused more on verifying that the results are repeatable under the same test conditions. Then as a second check when the test conditions change do you get the expected results. For example if you lower the test condition temperature does the capacity drop as much as you expect.

Ideally the LiFePO4 market will eventually get to a point where the consumer does not have to verify the supplier is actually sending you what you paid for on every single piece. Maybe we will only need the occasional spot check or it will become like buying a loaf of bread where I don’t have to worry that the loaf is two or three slices short.
 
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If you spend some money for quality and go to currentconnected.com, battle born, or Fortress, you will probably see better results. Shopping bottom of the barrel factory seconds off alibaba is not for you.
 
If you spend some money for quality and go to currentconnected.com, battle born, or Fortress, you will probably see better results. Shopping bottom of the barrel factory seconds off alibaba is not for you.
Docan isn't typically regarded as bottom of the barrel, though I don't think anyone really expects "grade A" from them either. I really don't know how many people here do full capacity tests to their cells either.

I haven't tested mine and I don't have a capacity tester (and they still aren't in service due to me having too many projects of higher priorities, sigh...).
 
When I retested my cells from Amy they always matched the provided test sheet. Both Grade A cells and grade A- cells.
I mean sure there was some variance but hey the EBC-A40L is literally the cheapest tester there is.
 
Docan isn't typically regarded as bottom of the barrel, though I don't think anyone really expects "grade A" from them either. I really don't know how many people here do full capacity tests to their cells either.

I haven't tested mine and I don't have a capacity tester (and they still aren't in service due to me having too many projects of higher priorities, sigh...).
Nope. My 230Ah's have been in service for about a year and never been below 50%. They just work really well, cells are well balanced, and they keep the lights on in the RV. One happy camper. My four cells were $450, not too much more than a quality pair of Trojan golf-cart batteries, with twice the capacity, at half the weight and size. They came from Docan Houston.
 
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These are grey market cells.

They don't meet some requirement for use in EV. More often than not, it's capacity.

It doesn't take much looking on this forum to find that this experience is the norm.

We are not being sold premium EV cells that meet data sheets for a small fraction of what the EV manufacturer's pay. Expecting that is the problem. Expecting Chinese vendors to meet typical "the customer is always right" consumer mentality is at best unrealistic.

My own 9 Eve 280Ah cells tested 263-279. @cinergi only had a handful above 280.

Again, this is normal. The reason you're not seeing more of it is that most people don't test their cells/batteries rigorously. And even fewer (if any) are testing with calibrated/correlated equipment.

Sorry you're disappointed. This is an expectation issue, not a cell/supplier issue. You just got 95% capacity cells for 50% the price.
 
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Maybe even 98% of rated depending on the accuracy of the tester. Possibly influenced by how low resistance the temporary hookups / cabling is during test.

The solution of course would be for manufacturers to de-rate their stated capacities just a hair, but for most that's not gonna' happen.
 
These are grey market cells.

They don't meet some requirement for use in EV. More often than not, it's capacity.

It doesn't take much looking on this forum to find that this experience is the norm.

We are not being sold premium EV cells that meet data sheets for a small fraction of what the EV manufacturer's pay. Expecting that is the problem. Expecting Chinese vendors to meet typical "the customer is always right" consumer mentality is at best unrealistic.

My own 9 Eve 280Ah cells tested 263-279. @cinergi only had a handful above 280.

Again, this is normal. The reason you're not seeing more of it is that most people don't test their cells/batteries rigorously. And even fewer (if any) are testing with calibrated/correlated equipment.

Sorry you're disappointed. This is an expectation issue, not a cell/supplier issue. You just got 95% capacity cells for 50% the price.
You are correct it is an expectation issue. I expect the supplier (Docan) to supply cells that meet their own claims. Not my personal claims. Not another suppliers claims. But Docan’s own claims made via Jenny Wu. Jenny Wu at Docan said these cells would meet 280Ah or they would make an adjustment to the price. We then negotiated a price based on what Jenny Wu ( Docan) said I would be receiving. They received 100% of the price we negotiated and I received 94% of the capacity they said would be provided. No adjustment to the price was made so I was ripped off.

As a buyer the fact that a brand new EVE cell might cost twice as much might make you feel better about the price you paid for under performing cells but you’re still ripped off. Like finding out the used car you purchased had its odometer rolled back. Yes, you paid less than if the car was brand new but you were still ripped off.
 
same issue here, same supplier, same cell, same experience (reveived them in September with manufacturing date around dec/jan)

IMG_20220925_131651~2.jpg


:(
 
Docan isn't typically regarded as bottom of the barrel, though I don't think anyone really expects "grade A" from them either. I really don't know how many people here do full capacity tests to their cells either.
I fully capacity tested all 8 of my 160Ah cells from Docan (Jenny Wu), and all exceeded spec.
 
I'm too far down the second hand 18650 powerwall journey to convert to LifePo4 but I'm interested...

Let me ask... the cells have a bit less than advertised capacity but are described as being in good shape. Is there any reason to believe you won't get the expected number of cycles? In other words, is there linkage between false capacity advertising (but good looking cells) and an implication that you won't have a reasonable operational experience?

Also I noticed the OP talked about an initial purchase and then follow up for more. That's been the number one issue for my 18650 journey over the last 3 years. As I've expanded the battery bank, I've continue to make purchases and Its never consistent from year to year. It adds stress.
 
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