So here it goes. So many ppl are getting into the DIY Lithium battery game. So what makes a lithium battery cell quality or not so quality. For a start it must test above its rated capacity if bought from a trusted source. 

How to test? Using the ZKE tech Battery load tester. I have purchased & shipped cells from quality suppliers & have not been disappointed yet. All have tested above specification on delivery & the cells have delivered close to 8MW of energy through the last year & they still doing very good duty in the field. 

These cells were CALB & EVE manufactured Grade A & tested to be the real deal. The batches were 100ah, 120ah & 235ah. They all tested on average at 105ah, 127ah & 240ah consistently during a full discharge & recharge at 40A. 

I am currently busy with a batch of allegedly 280ah EVE cells that I'm still busy capacity testing. So far 8 tested only 2 have made it above 280ah capacity. The rest are anywhere between 271ah & 276ah. Beware guys try not buy rubbish. Stick to a trusted source otherwise you may just burn your fingers or your wallet. When you capacity test there is absolutely no place to hide. Its a true reflection of what you have paid for. 

 

The battery will always behave as bad as the weakest cell. 

9 hours ago, Steve87 said:

So here it goes. So many ppl are getting into the DIY Lithium battery game. So what makes a lithium battery cell quality or not so quality. For a start it must test above its rated capacity if bought from a trusted source. 

How to test? Using the ZKE tech Battery load tester. I have purchased & shipped cells from quality suppliers & have not been disappointed yet. All have tested above specification on delivery & the cells have delivered close to 8MW of energy through the last year & they still doing very good duty in the field. 

These cells were CALB & EVE manufactured Grade A & tested to be the real deal. The batches were 100ah, 120ah & 235ah. They all tested on average at 105ah, 127ah & 240ah consistently during a full discharge & recharge at 40A. 

I am currently busy with a batch of allegedly 280ah EVE cells that I'm still busy capacity testing. So far 8 tested only 2 have made it above 280ah capacity. The rest are anywhere between 271ah & 276ah. Beware guys try not buy rubbish. Stick to a trusted source otherwise you may just burn your fingers or your wallet. When you capacity test there is absolutely no place to hide. Its a true reflection of what you have paid for. 

 

That is normal for the eve 280Ah. Most of them test closer to 270Ah. They are still eve cells though. Funny that it's only happening with the 280Ah cells though. The eve 304Ah are testing between 310-320Ah

Works nicely for top balancing as well👍🏻

58 minutes ago, Chris_S said:

That is normal for the eve 280Ah.

I'm sorry I disagree with you on this point. I have shipped the EVE 280ah before & not a single cell tested below 288ah. 

I think you guys are dealing with an inferior batch there or an inferior distributor that has taken your money for the 280ah cells & sold you Grade B. They are only Grade B for the reason of not making capacity. For no other reason. They are EVE indeed but not the quality that I have become accustomed to. 

Furthermore in my dealings with my supplier in China such a demonstration of inferior quality would warrant a new batched shipped out immediately. I have seen the guy who sold these say there is a 5 yr warranty with the supplier in China. Now what is the point of that warranty if on delivery the cell is below par on capacity. 

My humble apologies. I am very strict on quality control & that is the reason one invests in equipment of this nature. To be able to call out the problem & then deal with it. 

The 272ah Lishen cells are cheaper & for a reason they test around 276ah.  In my opinion you guys have accepted lower Grade B cells & are supporting the distributor by not raising the issue & dealing with it. 

If I pay for 280ah cells I want nothing less than 280ah in that cell otherwise I'm not happy. The same must surely be true if you buy a 8kW Sunsynk & at 7kW it trips from overload. Maybe I am missing something here or maybe not. 

It's always good to sell a product to a customer but then remove yourself from the situation when things are what they were made up to be. I have seen similar issues arise on the other oversees forum & it's funny because I see the same playing out here. 

It's not pleasant to be taken for a ride whether that was intentional or not. This is the nature of buying cells from a far away place. I would say throw the ball back in the court of the distributor. Get them to take responsibility for the Grade B. 

49 minutes ago, Steve87 said:

I'm sorry I disagree with you on this point. I have shipped the EVE 280ah before & not a single cell tested below 288ah. 

I think you guys are dealing with an inferior batch there or an inferior distributor that has taken your money for the 280ah cells & sold you Grade B. They are only Grade B for the reason of not making capacity. For no other reason. They are EVE indeed but not the quality that I have become accustomed to. 

Furthermore in my dealings with my supplier in China such a demonstration of inferior quality would warrant a new batched shipped out immediately. I have seen the guy who sold these say there is a 5 yr warranty with the supplier in China. Now what is the point of that warranty if on delivery the cell is below par on capacity. 

My humble apologies. I am very strict on quality control & that is the reason one invests in equipment of this nature. To be able to call out the problem & then deal with it. 

The 272ah Lishen cells are cheaper & for a reason they test around 276ah.  In my opinion you guys have accepted lower Grade B cells & are supporting the distributor by not raising the issue & dealing with it. 

If I pay for 280ah cells I want nothing less than 280ah in that cell otherwise I'm not happy. The same must surely be true if you buy a 8kW Sunsynk & at 7kW it trips from overload. Maybe I am missing something here or maybe not. 

It's always good to sell a product to a customer but then remove yourself from the situation when things are what they were made up to be. I have seen similar issues arise on the other oversees forum & it's funny because I see the same playing out here. 

It's not pleasant to be taken for a ride whether that was intentional or not. This is the nature of buying cells from a far away place. I would say throw the ball back in the court of the distributor. Get them to take responsibility for the Grade B. 

I hear you. If look you have a look over on diysolarforum.com you will see that this has been going on with the 280Ah cells for a while. I can't say why it is. Could be that they are harder to get now in China. I have no idea. That's why people are moving over to the 304Ah cells. 

Sure there might still be batches around that will test over 280Ah but I think that is a scarcity now on that specific cell. 

17 hours ago, Steve87 said:

So many ppl are getting into the DIY Lithium battery game

Is it cheaper to do say 15cell EVE batt with BMS 100Ah compared to just a pylontech 100Ah?

Or is it more expensive, and if so, then what are the benefits to this DIY?

Apologies if off topic.

@Steve87 i would have to agree with you on this, just one thing if it's A Grade cell the supplier would have done and initial capacity test to verify the capacity and protect themselves if and issue were to arise due to capacity testing. Why pay A Grade price when it's not. 

 

Edited March 14, 20232 yr by Raj35

1 hour ago, Raj35 said:

@Steve87 i would have to agree with you on this, just one thing if it's A Grade cell the supplier would have done and initial capacity test to verify the capacity and protect themselves if and issue were to arise due to capacity testing. Why pay A Grade price when it's not. 

 

I think Steve has already dealt with that. 

I'm diabetic. I have learned to be very wary of branding re sugar content and of promises made by restaurants. Many years ago I was what would these days be called a "lacto vegetarian". I learned to read lists of ingredients very, very carefully. 

It's very easy to advertise something as doing this or that. Steve is testing those claims, because at the end of the day it's his reputation that will stand or fall on those cells, not the guy he imported them from.

280Ah or 274Ah or even 270Ah much of a nothingness to me - come on its less than 5% difference.

Might be the case for you. Less than 5% but the difference in dollar terms is significant. Imagine if you could buy a cell of the exact same testing capacity of these for $10 - $15 less per unit cell. That adds up X 16 cells or whatever quantity you bought. 

I fully share your point of view the cells are still usable & very much so. But don't sell me or a client a product that you call Grade A at the Grade A price when it's not. 

Sort of becomes the same as some installers that quote a 545W mono JA solar panel & install a 400W Tier B panel. It's just not fully transparent is it. 

I'd much rather buy the Grade B knowingly so & then have less expectations & accept those shortcomings happily. 

But I'm not so sure anymore I think maybe some ppl don't mind this sort of thing unfortunately it's not in my taste. 

10 hours ago, Steve87 said:

Might be the case for you. Less than 5% but the difference in dollar terms is significant. Imagine if you could buy a cell of the exact same testing capacity of these for $10 - $15 less per unit cell. That adds up X 16 cells or whatever quantity you bought. 

I fully share your point of view the cells are still usable & very much so. But don't sell me or a client a product that you call Grade A at the Grade A price when it's not. 

Sort of becomes the same as some installers that quote a 545W mono JA solar panel & install a 400W Tier B panel. It's just not fully transparent is it. 

I'd much rather buy the Grade B knowingly so & then have less expectations & accept those shortcomings happily. 

But I'm not so sure anymore I think maybe some ppl don't mind this sort of thing unfortunately it's not in my taste. 

Actually what constitutes grade A and B these days? There really is no official grading like this. Best cells go to EV's lower quality goes to storage grade. A genuine what you would call A grade is new cells directly from a company like eve. At a much higher price

Best I have seen some suppliers do is refund a few % for the missing capacity. Definitely not $10-$15 per cell

1 hour ago, Chris_S said:

Best I have seen some suppliers do is refund a few % for the missing capacity. Definitely not $10-$15 per cell

Get pricing for the 272ah Lishens. Price difference is that.

@Steve87, here is a video for you:

 

Watched it already. A big aspect of what Andy misses here is the price paid for each. I wont spend money on below to par cells when cheaper spec 272ah tests to the same capacity & costs less. That's just my opinion. Andy as well as others are more than entitled to their own opinion & can draw their own conclusions based not on this video but from experience. 

But got to give it to Andy he is a Pioneer in this battery testing, building game. A few more Spats to him for sure.