Shenzhen Basen 280AH Issue

[Gazoo]

In this case, the weakest cell becomes even weaker, because more discharged than the other cells.

Not if the cells are kept between the knees. I only have a 5mv to 10mv difference while charging and discharging.

The question is, how strong should this DC-DC per cell be,
to handle most of cells in most situations?

That would be my question too. What would it take to keep them equalized, 5 amps, 10 amps....I don't know.

 

[Marinepower]

That is possible but there is no way of knowing that for sure. I think lately there have been more orders and therefore more capacity testing. Had I tested each cell I have no doubt I would have been able to achieve a greater average capacity. Another point is most keep their cells between the knees to "prolong" life anyways. So in the end, most don't charge and discharge fully and are using 80% capacity. Everyone is welcome to order directly from EVE and pay the price for binned and matched cells. I have been able to get 272ah's out of my pack and I am satisfied for what I paid for them in the group buy.

Gazoo, it just occurred to me that as there was a shortage of these eve 280 cells due to their popularity, its possible that the suppliers are reaching further down the quality scale to meet supply. But as you say, if there are more recent customers, maybe we hear more problems user are having but the overall % or problem cells remains the same.

I don't care about the total capacity of the cells as much as the cells remaining in balance over time. So their capacity relative to each other in the same series bank is my priority.

Anyways, my cells are en-route from China so only one way to find out. Mine are also supplied from Basen, so relevant to this thread. I'll report back when they arrive and I have had a chance to test.

 

[Gazoo]

I don't care about the total capacity of the cells as much as the cells remaining in balance over time. So their capacity relative to each other in the same series bank is my priority.

Wouldn't the cells remain in balance if the IR of the cells is relatively close? I have to trust Basen's testing. I don't have an IR tester.

 

[Marinepower]

Wouldn't the cells remain in balance if the IR of the cells is relatively close? I have to trust Basen's testing. I don't have an IR tester.

I'm not an expert but i thought that IR and cell capacity are related/correlated?

 

[Honuz]

That is possible but there is no way of knowing that for sure. I think lately there have been more orders and therefore more capacity testing. Had I tested each cell I have no doubt I would have been able to achieve a greater average capacity. Another point is most keep their cells between the knees to "prolong" life anyways. So in the end, most don't charge and discharge fully and are using 80% capacity. Everyone is welcome to order directly from EVE and pay the price for binned and matched cells. I have been able to get 272ah's out of my pack and I am satisfied for what I paid for them in the group buy.

Now we will have some "I swap my 272ah and 20$ for a 278ah cell to match the rest of my pack"....?

 

[TGPB]

I have been going round and round with the seller to get 1 cell replaced....not impressed with their customer service.

 

[TGPB]

Seller is suggesting I get an active balancer to remedy the issue. I'm concerned this is just masking a cell with issues and it will bite me down the road

 

[Gazoo]

View attachment 26638
After doing the parallel balance charging on the first 4 cells I decided to put a load test on the cells. Here are the results. All 8 cells arrived at 3.29v each. I broke them up into 2 x 4 cell groups. I Top balance charged the first battery to 3.40v then finished it off at 3.65v I then put it together in a 12v configuration, connected the BMS. I then hooked up my voltage sensing relay to make sure it would come on at 12.0v. I put a 180w load on the batteries and set the BMS to shut down at 2.5 v. It was at 12.3 volts when I left it for about an hour. I came back and the BMS had shut it down.

I'm currently testing the 2nd battery.

280AH Battery

My 8 cells connected in series look vey similar to your 4 cells. If you got 277ah's you did good. I got 272ah's and I can live with that.

 

[Steve_S]

I have to chime in. RED FLAG ! Vendor is a putz. No Balancer, BMS or device, in general, can fix a dud battery cell.
Also your "expectations" may be slightly tainted.

have a gander at this, may answer some things:
STATUS of ESS/Storage Cells being purchased. (commodity cells) (diysolarforum.com)

 

[TGPB]

I have to chime in. RED FLAG ! Vendor is a putz. No Balancer, BMS or device, in general, can fix a dud battery cell.
Also your "expectations" may be slightly tainted.

have a gander at this, may answer some things:
STATUS of ESS/Storage Cells being purchased. (commodity cells) (diysolarforum.com)

Good read. I was shooting for 3.0 to 3.4 in my range. The one cell takes off before they get to 3.4. That's my issue.

 

[Steve_S]

Well to put it simply.
The only option left to try is to manually cycle it Bottom to Top balance and trickle it up to full, cross finger and hope for the best.

Come Mid-Late December some folks are going to be having kinipshin's... Ohhh Boy....
January will see much changes at some vendors, pricing and quality graded level cells and "real" Matched, Batched & Binned, qualified & guaranteed" cells. Backed by Manufacturer. The floggers are about to get a flogging. Gonna be fun to watch this.
That is as much hint I can leak.... aside from watch CATL, CALB, BYD & EVE...

 

[TGPB]

Well to put it simply.
The only option left to try is to manually cycle it Bottom to Top balance and trickle it up to full, cross finger and hope for the best.

Come Mid-Late December some folks are going to be having kinipshin's... Ohhh Boy....
January will see much changes at some vendors, pricing and quality graded level cells and "real" Matched, Batched & Binned, qualified & guaranteed" cells. Backed by Manufacturer. The floggers are about to get a flogging. Gonna be fun to watch this.
That is as much hint I can leak.... aside from watch CATL, CALB, BYD & EVE...

I was going to get some more cells....should I get them now or wait?

 

[Ampster]

I was going to get some more cells....should I get them now or wait?

I think it depends on your expectations If you want perfect cell matching then I would wait.Or I would buy CALB cells at $300 per kWh which will be perfecly matched. If you are like me and you can live with some imperfections you could order anytime. My expectations were that I I was getting cells for approximately $120 per kWh and I was going to use them to about 80 percent of the stated capacity. Therefore I was purchasing cells at a price of $150 per kWh of useable capacity. For the most part that has been what has happened.

My system is on grid but my original purchase was to reduce my consumption by setting by system to Self Consumption mode. With Cold weather my off the grid consumption has gone up as the solar insolation has gone down and I am pushing my pack harder than I had originally anticipated. I could blame the cells for not being able to deliver more capacity but I want long life and do not want to push them further. Therefore I have decided to buy more cells to increase my pack by 14 kWhr. I will still only run them to about 90 percent and take them down to maybe 20 percent.

Bottom line it is all about value, and it always depends on where you are standing. I came from a mode of running load shifting for a few hours a day on used Nissan Leaf cells to being 80 percent off grid for most of my usage.

 

[Steve_S]

I was going to get some more cells....should I get them now or wait?

Like our friend Ampster says, it's your call.
So I'll toss this log into the Ponderance Fire...
You can buy 280 Commodity cells, live within the 3.2-3.4V curve (where most of the juice is) $80 a cell.
Or you could buy 280 Matched & Binned giving you 2.800 to 3.550 and no runners for $120 per cell ?
There is llittle below 3.0 as it is a cliff fall from that point.
Above 3.500 again is also minimal as that the upper Hockey Stick. Charge to 3.65 till Amps taken = 0, within an hour the LFP will settle around 3.555 +/- a bit anyways (it's the chemistry).

Your wallet, your choice, there are pros & cons of course... Runner cells are a PAIN IN THE U-Know ! The diverge, trigger LVD or HVD while the others may be fairly apart... Commodity cells seem to be consistent in that they can diverge by 1mv per AH capacity. So a 280AH cells diverge to 280MV. This makes Perfectionists & nitpickers insane... some of that is evidenced here in the forums. OCD takes many forms LMAO, especially these days with everyone so On Edge.

 

[TGPB]

I had intentions of running my cells in the 3.0-3.4 range. I'm still hoping to make this happen if I can overcome this one cell that is mucking that plan up. I have ordered Heltec 3S 4S Active Balancer to see if it will solve my problem.

​

 

[leblancexplores]

I am seeing a lot of post lately of forum users having capacity issues or balancing issues with these EVE 280 cells. I wonder if the quality of the grey market cells is declining because of shortages? I recently (October) ordered 4 cells which are on their way, so I have will have to test them carefully when they arrive. Maybe $80 for 280 amp hours is just too good to be true...?

Dang I lucked out and got ETL cells. I can’t recommend them, enough. At .2 discharge I get 304Ah from a 280Ah pack.

 

[leblancexplores]

I had intentions of running my cells in the 3.0-3.4 range. I'm still hoping to make this happen if I can overcome this one cell that is mucking that plan up. I have ordered Heltec 3S 4S Active Balancer to see if it will solve my problem.

​

I started researching these and everyone said most if not all active balances are crap.

 

[leblancexplores]

I had intentions of running my cells in the 3.0-3.4 range. I'm still hoping to make this happen if I can overcome this one cell that is mucking that plan up. I have ordered Heltec 3S 4S Active Balancer to see if it will solve my problem.

​

Hah did you see the review?