What is going on here? Just got ZKE-40

[houseofancients]

If EVE has been fudging their test reports I suspect their tier 0 customers will figure it out.
I doubt they care about us the big customers are a different story.

well, not at all sure what is going on with these cells, but they seem to be the only ones behaving like this
weather we are all getting rejects, or there is an issue with this entire cell series....
dont know, but iḿ staying well clear of them

 

[Alkaline]

If EVE has been fudging their test reports I suspect their tier 0 customers will figure it out.
I doubt they care about us but the big customers are a different story.

I'm telling you there has been a rumor going around that they lost a big car contract and are selling these cells now with terminals on them and other things. I think the guy Lfpinside from Gobel power knows. The reason for the cancelation was because of quality.

Lastly the official data sheet of the LF280K only tests it from Storage Grade Cell no longer electric vehicle traction battery.

 

[Ellcon123]

Everything Sunshine_eggo said, becoming white noise. More energy being wasted on testing than using the cells. Usable range is 3~3.4V so will always be under max capacity. I've never tested a cell but for 2 years my packs have been operating to capacity, at least according to the BMS's. Good enough for me.

 

[740GLE]

Agreed I’ve never tested my cells, but then again I’ve never been in a situation where I need every Ah, wh.

 

[houseofancients]

Agreed I’ve never tested my cells, but then again I’ve never been in a situation where I need every Ah, wh.

i by default test my cells..
par coincidence once done they are top balanced too , two flies, one stroke

 

[Ellcon123]

I haven't top balanced for the same reason of wasting energy and the stuffing around. Get them together and start using. The balancer sorts them out quick enough and they have been running fine for years.

 

[houseofancients]

I haven't top balanced for the same reason of wasting energy and the stuffing around. Get them together and start using. The balancer sorts them out quick enough and they have been running fine for years.

to each it's own i guess..
energy comes from the sun.
i'd rather know for sure what is going on with my cells/batteries before exposing them to my expensive equipment/other battery pack, or cause them to overheat/vent in my battery room..

but that is just me

 

[Alkaline]

I don't like this Hakuna Matata way of managing your batteries...

 

[Ellcon123]

How can any of this overheat/vent or cause damage to equipment? These discussions are about Ah capacity, buying cheap from China, and did I get ripped off. There are so many variables and worrying about % Ah differences is not important IMO.

 

[Alkaline]

Wait till you build a pack and 1 lousey cell ruins the whole thing, your battery pack is only as good as the weakest cell. The larger the pack the more likelihood goes back.

Some people that are building 16s setups... well all it will take 1 bad grade B cell to make that whole pack worthless, now you have to go and find a replacement.

That being said my Basen 8s is not as bad as my XUBA 8s which has 2 weakcells, they do not like being discharged harder than 70 amps, which I need from time to time.

The luyuan cell setup has no issues at all, I can amp out my overkill 120 bms and they don't care.

In my 8s setups, if 7 of my cells are 280, but 1 is 258, guess what my entire pack is now a 258 doesn't matter what the other cells are.

So you'll need to have 1-2 cells extra.

I can not stand this, time wasting, anger inducing, life shortening grade B stress...

 

[TomC4306]

Have you tried doing a discharge test with your PSU stunt doubling for a battery?

What?

 

[John Frum]

.

 

[sunshine_eggo]

I can not stand this, time wasting, anger inducing, life shortening grade B stress...

Maybe this isn't for you?

 

[Alkaline]

Maybe this isn't for you?

You are right it isn't and I won't be DIY any thing in the future... Next purchase will be some generic retail batteries (chins, ampere time, redodo) and I won't care if its grade B, if It dies in 2-3 years, I'll just get a new one.

 

[BradCagle]

You are right it isn't and I won't be DIY any thing in the future... Next purchase will be some generic retail batteries (chins, ampere time, redodo) and I won't care if its grade B, if It dies in 2-3 years, I'll just get a new one.

Checkout the Timeusb, their 12.8v 100Ah pro is only $269
I did a review, capacity test, and teardown. It's good

 

[Alkaline]

Dear customer, I’m Sunny from Basengreen after-sales services department. Please let me know if I can answer any questions or forward your issue to our after-sales services team.

You can also email to info@basengroup.com, we’ll be very happy to help!

Oh how nice, I think I must have emailed them 10 TIMES and no response ever!

What is going on here? Just got ZKE-40

Who are you talking to? I'm just going to assume its me. I won't bother you again. Sorry, I was just a groggy in the morning... I don't know how to do the things you were asking and assumed I had to buy more stuff and well I just lost it. ? If anyone can make a write up on to do the stuff you...

diysolarforum.com

in 2021 January I purchased 8 EVE280N cells from Alex Chen, he claimed they were grade A perfect grade. Only reason I bought them because Lithiumsolar had done a review on them and was getting 282 or so. BUT The ones I got all were around 265 with 1 or 2 in the mid 70s. Alex Chen never responded to any of my chats and then finally after many attempts I got connected to Vicky who said Alex Chen has been promoted. Nice organizational structure you have there the bigger the charlatan the higher up they go.

btw, I"m assuming Basen and Basengreen are the same company, if not then ignore this. But you did respond to this thread so maybe you do have some connection to Basen.

So do I get 8 replacement cells?

 

[elen467]

Oh how nice, I think I must have emailed them 10 TIMES and no response ever!

What is going on here? Just got ZKE-40

Who are you talking to? I'm just going to assume its me. I won't bother you again. Sorry, I was just a groggy in the morning... I don't know how to do the things you were asking and assumed I had to buy more stuff and well I just lost it. ? If anyone can make a write up on to do the stuff you...

diysolarforum.com

in 2021 January I purchased 8 EVE280N cells from Alex Chen, he claimed they were grade A perfect grade. Only reason I bought them because Lithiumsolar had done a review on them and was getting 282 or so. BUT The ones I got all were around 265 with 1 or 2 in the mid 70s. Alex Chen never responded to any of my chats and then finally after many attempts I got connected to Vicky who said Alex Chen has been promoted. Nice organizational structure you have there the bigger the charlatan the higher up they go.

btw, I"m assuming Basen and Basengreen are the same company, if not then ignore this. But you did respond to this thread so maybe you do have some connection to Basen.

So do I get 8 replacement cells?

Dear Sir, sorry for the late reply, I was banned after my post last week and cannot reply to you. Could you please send us your order number ( 2021.01 order) by email? Then I’ll report to my leader to see how we can solve the problem for you ASAP.I sincerely apologize for your negative experiences and any inconvenience. Have a great day!

 

[Marinepower]

Oh how nice, I think I must have emailed them 10 TIMES and no response ever!

What is going on here? Just got ZKE-40

Who are you talking to? I'm just going to assume its me. I won't bother you again. Sorry, I was just a groggy in the morning... I don't know how to do the things you were asking and assumed I had to buy more stuff and well I just lost it. ? If anyone can make a write up on to do the stuff you...

diysolarforum.com

in 2021 January I purchased 8 EVE280N cells from Alex Chen, he claimed they were grade A perfect grade. Only reason I bought them because Lithiumsolar had done a review on them and was getting 282 or so. BUT The ones I got all were around 265 with 1 or 2 in the mid 70s. Alex Chen never responded to any of my chats and then finally after many attempts I got connected to Vicky who said Alex Chen has been promoted. Nice organizational structure you have there the bigger the charlatan the higher up they go.

btw, I"m assuming Basen and Basengreen are the same company, if not then ignore this. But you did respond to this thread so maybe you do have some connection to Basen.

So do I get 8 replacement cells?

I bought some EVE 280s from Alex while at Basen around the same time as you. They also tested out around 273 amp hours but they didn't have any major voltage drop when loaded and have stayed well balanced ( except some for annoying bus bar resistance issues, which are not the cell's fault ). So for me, that was a win.

BTW - i'm pretty sure that Alex Chen is a woman ( and not a 'he').

 

[Bud Martin]

Alex is a dude.

 

[rodrick]

Come on guy now days we’re not supposed to know it’s a surprise

 

[RCinFLA]

You can verify accuracy of zke by using a good shunt/battery monitor to verify load current (clamp-on meters are poor accuracy).

A good DVM can verify cell voltage. Make sure to take it on cell terminals.

I think you can trust the time accuracy but you can check that too if you want with an independent timer.

Curves look normal, just a little short on AH. It would help if you included a full charge cycle from xke after discharge. An approximate OCV can be determined by half the voltage between discharge and charge curves.

A better way to get OCV is allow three 5 minute rest periods to allow cell to recover to unloaded rested equilibrium voltage which generally takes about 5 minutes. Then about 3 minutes after load started again measure the voltage drop of rested OCV to 40A load after 3 minutes.

About 75%, 50%, and 25% SoC are good spots to include the 5 minute rest periods. Double check the rested voltage fully levels out in the five minute rest period. It might take a little longer at 25% state of charge. The xke will not include the rest periods of zero current in AH or wH calculation.

 

[RCinFLA]

Following up with a full recharge at same current (40A) done for discharge also provides other useful information.

Compare total wH for full discharge to total wH for full charge. The greater the percentage difference the more internal losses of cell. 96-97% wH recharge efficiency is about normal for a 280 AH at 40A discharge and recharge round trip. wH efficiency will be less than AH in versus AH out round trip efficiency due to the cell voltage vs SoC involved with wH calculations. A used cell will show up more wH round trip loss due to greater terminal voltage slump during discharge and voltage bump up during charging under cell current.

LFP cells have very similar discharge vs charge overpotential slump/bump for same discharge and recharge current.

ZKE-40 takes each voltage sample, multiplied by test current, and weights its time increment (watt-secs) to sum up total wH's.