Thanks for the comment. I just want to correct something. This batteries were bought brand new and were commissioned in March / April 2022. I did compress them and had them top balanced even though they were sold as grade A matched and batched. I paid much higher price for them than was what obtainable.OP kept great records of voltages back in 2022. Top end voltages looked to be 55.0 to 57.0V when fully charged.
I think many of us feel that 54.0 to 55.0V is more prudent especially if ambient temp > 30
The manufacturer recommended voltages are often higher but I think that this should be interpreted as a pulse peak voltage not a float/absorb/ boost voltage that is used with Pb Acid and conventional solar charging.
Pulse charging profiles are now showing up in DC-DC chargers in 12V systems.
We know LiFeP04 in the engine bay is a capacity killer. A YTube reviewer here in Australia has shown this and the battery company manufacturer wants to sue for defamation.
You have shown that JKBMS did a great job maintaining cell balance and out of balance pack is not responsible loss of capacity.
Thank you for sharing your real life experience with us. Our knowledge continues to advance from the summation of DIY user's experience.
Lastly I have 2 banks operating in parallel. The other bank is just fine.. capacity and all.
Different bank different Alibaba vendor.. rated Grade A - or home storage system.Same cell batch or different one?
I think it's a rhetorical question. Everyone has probably no doubt they should be fine.My concern is. Even if I charged those batteries at 57v is it enough to essentially render them technically discharged in 2 years? for home solar residential use?
Hopefully something good comes out of this.I am in touch with Amy and she promised to reach out to eve so fingers crossed but not holding out for much.
Great to have this. Thank you.For closure, here is the discharge curve (from ZKE battery tester ) after I discharged all the cells from 3.45 rest voltage after charging each cell to 3.6v.. It took me days to finished this but this result showed capacity when discharged to 2.7v
The screenshot attached shows the curve for 15 of 16 cell. One cell is missing because the computer restarted during the charge process. as you can see they all uniformly lost about 20% capacity.View attachment 236250
Do you know for sure that the cells had 280Ah capacity to start with?as you can see they all uniformly lost about 20% capacity.
The topic is very interesting and informative. I would like to see the continuation. How to find out what was the matter and why it happened. My new EVE MB31 314 Ah cells from Amy are on the way. I would hate to get the same result afterwards. Keep us posted. Thanks.
Steve_S, don't just post in person. We are very interested too, and need information on this issue. Write in the topic, if possible.
Yes I did run a capacity test on the bank as a whole when I first got them. The result hereDo you know for sure that the cells had 280Ah capacity to start with?
Well good for you. I also have a grade B cell which has no issues. From a different vendor but was paired with the grade A I got from Amy wan.. in a parallel which meant both were charged same way same room temp.. same everything.For what it is worth, I've got EVE LF280K grade B cells and JK BMS from Amy (Luyuan). Commissioned in december 2023. I use 3.45 V bulk, 3.375 V float. No cell compression. Zero problems, no bulge at all. I know it is just nine months, so maybe not much to go on. Just a try to put your mind at ease.
That sucks, but it is normal with Chinese companies in the lithium battery sector.For those asking.. I never got back from Amy Wan. I sent all the details she said you would get back to me and never did.
Good luck with your new cells.I have moved on and ordered a new set of battery. hopefully it fairs much better. This time I am also logging cell temperature and voltage. Thanks to everyone who offered suggestions and comment.
From reading this thread I think you've done all the analysis possible. But sometimes we get lemons, and there is nothing else to do than to move on. Good luck with your next battery set.Well good for you. I also have a grade B cell which has no issues. From a different vendor but was paired with the grade A I got from Amy wan.. in a parallel which meant both were charged same way same room temp.. same everything.
The Grade B is still in use and working very well, no bulge no issues.
For those asking.. I never got back from Amy Wan. I sent all the details she said you would get back to me and never did.
I don't hold a grudge nor do I expect any form of compensation or warranty claim. I am putting this out there for anyone. Warranty claims for these batteries are next to impossible to uphold.. even if you have all the data. I paid top dollars for this batteries.. way above what every other vendor charges but we all get L some day.
I have moved on and ordered a new set of battery. hopefully it fairs much better. This time I am also logging cell temperature and voltage. Thanks to everyone who offered suggestions and comment.
If there is any update I would post (only if Amy response cause I am done with the battery and disposed of them. I can not use something that lost capacity in such drastic fashion in than 2 years..) and I will answer questions posted here.
I prefer a system that will make me SWAN (Sleep Well At Night) Eve stated to toss a battery once it is at 80% of its og capacity. This one reached that in 2 years and added a belly to boot. LOL. I can trust it..They might settle on that 20% loss and perform well for you at that limit, don't toss them, run em hard !!!
I have similar issue with my REPT package similar working conditions as yours but mine lost 50% capacity in under 4 months!! They were only 20 cycles on them and lightly used mabe high soc killed them after replacing 5 cells now no issue yetHello everyone,
I got 16 EVE LF280K in march 2022, they were suppose to be Grade A cell purchased from Amy Wan. I got manufacturer spec sheet which included capacity for each cell, and showed they were manufactured in December 2021 (a month before they were shipped out to me). I set them up and commissioned them for use. initially used a JBD 200A BMS but later switched to the JK 200A bms with active balancer. Before using the cells I top balanced them by putting them all in parallel and using a power supply unit (the type recommended here) and charging them up to the recommended 3.64v.
View attachment 234595
The assembled them into 16S config and built a compression system for the batteries. The charge voltage was 3.55 per cell and average charge current was between 50A. I leave completely off-grid. I set low discharge cut off to 2.8v but I rarely ever get to that point maybe 3 to 4 times in a year.
View attachment 234596
Ambient temperature in my country ranges from 25C to as high as 38C (the 3 month long hot season) for the rest of the year it stays around 29-30C (all indoor temperatures)
April 2023, I added another bank of 16S grade to increase my capacity to 580Ah at 52v. I used the oppotunity to top balance the batteries this time using the ZKE tes battery tester. I put them all in parallel and charged them to 3.65v.
I also improved on the battery stand by reinforcing the compression with angle iron bar.
The new battery stand with 2023 bank is at the top. 2022 is at the bottom
View attachment 234597
Sometimes in april 2024, I noticed that the 2022 battery were using the "wrong" capacity on the BMS. The BMS was using a capacity of 266Ah instead of 280Ah. I naturally assumed this was due to JK voltage drifting and followed some step to calibrate it. I also noticed that the cells seem kind bulgy.. but it was hard to know due to the compression and the well the cells were located.
View attachment 234603
I decided to add another bank this year and move all my battery into the DIY lithium battery kit that is the vogue now adays. This meant I had to dismantle all the cells. It was when I noticed that the 2022 cell have swollen and bulged. (The picture attached) I also noticed they were warm to touch (not hot).
View attachment 234598View attachment 234600
before removing them, the plan was to do a top balance so I initially used the solar controller to charge them all to 3.6 cells. The funny thing is, all the cells where balanced with voltage difference of not more than 0.007. This means the cells were fully charged. I decided to test their capacity using the ZKE tester and I got between 225Ah and 221Ah. This means the batteries lost 20% of their capacity in the space of 2 years
The problem is, I don't know what could have cost this rapid degradation, I am suspecting the relative high charge? I swicthed all my cells charge to 3.45 some 3 months ago.. I charge them sometimes with about 75A could that be the reason? or the relative high ambience of 38C (during the hot season).
My second question is, can I still use this cells? or they are dangerous to use. Like I said, tjhey all well balanced and seems the loss of capacity was even across the cells.
I would appreciate your take on this, has anyone experienced this before. What can I do to prevent this from happening in future to my other cell. Could this have been a case of bad battery batch?
I have attached the ZKE discharge log of one of the degraded cells
I pulled off the black top of one of the cells to make sure they were not relabelled QR code. (pictures attached)
View attachment 234599
High temp seems to be some of the cause but I have to wonder if compression would helped. I will be pulling 16 cells from my bank soon, these have had compression using poron compressed 25%. I'll update when I pull those. I'm not expecting any cell swelling.I have similar issue with my REPT package similar working conditions as yours but mine lost 50% capacity in under 4 months!! They were only 20 cycles on them and lightly used mabe high soc killed them after replacing 5 cells now no issue yet
Check out this video replacing 3 cells
Will you be dropping soc prior to tear down? Seems like that would reduce any potential swelling tendency, after having recommended pressure throughout their life previouslyHigh temp seems to be some of the cause but I have to wonder if compression would helped. I will be pulling 16 cells from my bank soon, these have had compression using poron compressed 25%. I'll update when I pull those. I'm not expecting any cell swelling.
I will pull them at whatever charge the cells are at. Most likely those are heading for a Luyuan box and the cells currently in the box are heading for my shop battery bank. Shop battery bank will then be 72 Kwh instead of the original 58 Kwh I had planned.Will you be dropping soc prior to tear down? Seems like that would reduce any potential swelling tendency, after having recommended pressure throughout their life previously
I finally moved them to a shelf with ton of compression
By the way I have 2 105ah eve packages next to them the cells produced in 2019, I tested the capacity few months ago the gave 94AH.
It looks like an assorted medley of cells at least going by the heights?I finally moved them to a shelf with ton of compression