Sixtysix 280ah Cells from Deligreen

[ArthurEld]

Mine were pretty flat when I received them and they still are pretty flat. I just noticed I could see a little more space near the corners.
I left my threaded rod a little long so I can cut it in half and make two rods for my smaller battery configuration.

edit- I'm charging 1 cell but it's compressed with 15 other cells in one row with no busbars.

 

[Steve_S]

I purchased a pre-assembled battery pack last year (The ShunBin Disaster). When I pulled the cells out of the casing they were very well bound with fibre strapping (like that used on binding pallets of boxes together). When I cut that strapping to release the cells, the cells expanded a little (fortunately, while being Used Cells they had obviously not been abused. Once I squeezed them gently to re-strap them into their new configuration hey were fine.

The ShunBin Pack sold on Amazon as New 24/400AH actually had 16X Used 175AH Cells... Hence the "ShunBin Disaster".

 

[ArthurEld]

I purchased a pre-assembled battery pack last year (The ShunBin Disaster). When I pulled the cells out of the casing they were very well bound with fibre strapping (like that used on binding pallets of boxes together). When I cut that strapping to release the cells, the cells expanded a little (fortunately, while being Used Cells they had obviously not been abused. Once I squeezed them gently to re-strap them into their new configuration hey were fine.

The ShunBin Pack sold on Amazon as New 24/400AH actually had 16X Used 175AH Cells... Hence the "ShunBin Disaster".

Didn't Amazon help you get your money back?

 

[Steve_S]

I wrote it all up, it's on here.
Amazon didn't help, shipped direct from vendor. I did eventually get a part refund for the AH discrepency which covered the cost of the first rebuild which included replacing the BMS that came with it, bus bars and wiring. Actually, changing that crappy BMS is what started the whole Chargery BMS thing here as that is when I started the threads after getting my Chargery and then started working with Jason to add Cold Temp support + other updates, including the development of the DCC's and now working with him in regards to the new BMS' with Active Balancing and more... due at end of year or early 2021.

Here is the painfully long thread, if youre totally bored

ShunBin Battery Packs: 12V/24V 100AH and up ! A Complete RIP-OFF ! AVOID

EDIT OCTOBER 2020 ! WARNING !!! ShunBin IS A RIP OFF ! The sell "Advertise 24V/400AH" What they sent was 24V/350AH with USED / ABUSED 175AH cells. I did not update this previously on Page 1, because I thought people would look through the thread. Now I learned some are not. PLEASE...

diysolarforum.com

 

[ArthurEld]

I'm doing a capacity test on one cell. It looks like it will take about 10 hours to finish the test on one cell.

This is the tester I am using but they aren't available anymore - https://www.aliexpress.com/item/32822564230.html
They must have updated them. I see some have bluetooth now.
I have another one on the way from China. I have 66 cells to test. It's twice as fast with two testers.

The tester draws 24A. I used 12 awg wire and a 30A fuse. The wires are getting warm.

I noticed the resistance value seems more in line with what others have reported. When I started the test the display showed .12 resistance. When I got to about 75Ah the value changed to .11. I don't even know if that resistance has anything to do with internal resistance. I still don't have the internal resistance tester I ordered.

I will record the info on my spreadsheet to see if I notice anything useful.

 

[Dhopewell]

I have no idea. But even if they did isn't it possible the cell would expand after being removed from the clamp? I also wonder what happens when the cells are discharged after expanding. Do they contract?

The ones I’ve had swell do not shrink. They can generate very high internal pressure from gas. One swelled so much I decided to experiment on it and put a small hole in since it didn’t vent. Based on the smell I think the gas is ethylene and the likely source decomposing ethylene carbonate electrolyte - a one way process. I’m still cycling it in a 1v pack as an experiment, and so far the cell continues to maintain voltage and charge.

 

[Gazoo]

The ones I’ve had swell do not shrink. They can generate very high internal pressure from gas. One swelled so much I decided to experiment on it and put a small hole in since it didn’t vent. Based on the smell I think the gas is ethylene and the likely source decomposing ethylene carbonate electrolyte - a one way process. I’m still cycling it in a 1v pack as an experiment, and so far the cell continues to maintain voltage and charge.

That's what I thought. EVE says 2mm expansion is normal. I am pretty sure one of my cell is a little more than that and they were delivered that way. I was able to arrange them so I could make a square pack with 8 cells. The ends where I will mount the plywood are fairly even so I think I will be ok.

 

[ArthurEld]

There was a hurricane getting kind of close to us so I decided to charge up more of my cells.

I bought a 3000W 12V inverter from Harbor Freight. I've got battery backup!

I think my cells could keep us going for a week in the state of charge I got them from China. I need to charge them for top balance anyway.

It's been downgraded to a tropical storm. We're at 65 feet elevation, my house is cinder block and I have hurricane windows and doors.

I can return the inverter. But I will research and buy a different one. It's good to have portable power.

 

[ArthurEld]

We survived the storm without incident. So, I will return the unused inverter.

Since I started charging more cells, I will top balance another 16 and assemble a 48V battery.
Then I'll discharge the battery to check the capacity. Then I'll charge it to see how the cells stay together.
I will use my BMS and battery meter to see what I can find out. I won't use balancing.

I've been using my Mean Well 3.3V 120A power supply for charging cells parallel. There is only one adjustment screw on the Mean Well.
I back the screw out so it won't start charging when I turn on the power. There's no power switch on the Mean Well so I use a power strip.
I connect a clamp meter and voltmeter and adjust the screw until I'm charging at 50A. I watch the volts but I know it is lower than my target.
If I set the volts to my target, it will charge at 120A. I am not in that much of a hurry.
I keep adjusting the voltage to stay between 40A and 50A. But I watch the voltage on the output screws as I am adjusting and when I get to 3.61V I stop adjusting the screw. Since I am in CV mode the amps are dropping as I approach the target. The volts are also rising quickly because there's hardly any amp hours left to use. I keep checking the battery until it reads 3.6V then I turn off the power supply. Since I am so close to 3.61V the power supply is only putting out 2A when I turn it off.

 

[michael d]

You know... I'm gonna just be blunt about it. Undersizing is very easy to do. Being "cheap" and bodging thing (squeezing copper pipe, seriously ?) is certainly NOT the way to buy a solid & reliable system. Cheap is NOT Equal to Frugal !
Wanna build a 1000HP Corvette and put Brakes from a 1976 Chevette on it with Bicycle tires ?
Oversizing a little over is generally a good idea because Things Happen, often unexpectedly and then sometimes just evolution because needs / wants change.

I always told people that if you figure everything out and decide that a 4Kw Inverter (excl, surge) would be OK I would suggest get the Next Size up but guess what, I'd get CRapped on for it. Then a year later Mr Smarty is upgrading their Inverter.... I don't tell folks anymore cause I don't need to be crapped on for common sense.

I first built to run with 3KW Inverter with Big Lead Battery Bank, 12 months later I was upgrading to 4KW Inverter... Replaced ALL my 2/0 with 4/0 ($$$ ouch ) new breakers, fuses (more $$$ ouch) then to incorporate Lithium (LFP) another year afterwards... more $$$
BOS = Lots of cash and if you built to one spec at first, the odds are you will be upgrading something later. BTW, just about everyone who goes solar does upgrade some things within 12-36 months to increased need or just under planned at the start.

As the 500A Charge / Discharge.... the 280AH cells are C1 (280A) max output rate (for the commodity cells) and they are recommended to not exceed .5C

I read that long thread between you and Smoothjoey... made my brain hurt.... be careful about getting caught up in minutia.

Please do yourself a favour, remember these are Commodity Cells and not fully matched & batched Premium cells. Ensure your expectations match what you bought.

Just a tidbit of personal info. I was an Core IT System Engineer (Military & Gov) and involved in fault tolerance & failover systems, which encompassed literally every aspect and potential scenarios... Triple Redundancy = Critical life ! Hence where I gained my "hard wired programming" of "Do it right the 1st Time." There is not much room for "just good enough". As I am Offgrid, Rural & Remote and can be subjected to "extreme" weather (1 foot + snowfalls) to twisters in summer ++ I have to depend on my system because I could be property bound for periods... dependability, reliability & safe are essential and approached as such.

yes, I am working toward the redundant system. I had a power outage 1x for 3 days and used a kerosene heater to keep from freezing. the kerosene heater backfired in the middle of the night when we were all under blankets trying to stay somewhat warm. it blacked everything in the house with soot and essentially all of the clothes were ruined even by going to the dry clearers with the specialty cleanup crew. $10000 dollars damage. had insurance but I prefer to not be without power and learn from my dumb mistakes of 30 years past.

 

[ArthurEld]

Here's the Mean Well connected to 9 cells in parallel. I have 16 on the workbench and you can see the capacity tester going.
This power supply needs six 6 awg cables because it's 120A and the connectors are small. I have never noticed anything to get warm.
The fuse is 125A but I only use 50A from the power supply.

 

[ArthurEld]

I still haven't found much difference between cells. The capacity varies +/- 3Ah.
The resistance doesn't very much at all. I find one that is .01 different now and then. But usually if I go back and check it later it's the same as the rest.

My test equipment is cheap from China so I don't even know if I can trust the results.
So far I burned up a couple battery meters and a capacity tester. I don't even know why the battery meters burned up.
I destroyed a capacity tester because I wasn't thinking when I connected it to my 48V battery and I cranked up the amps.
Since it can only handle 185W I really can't use much more than 3A.
Good thing this stuff is cheap. I just toss it in the trash.

I have my BMS and the other capacity tester connected to a 48V battery pack that I top balanced.
I don't expect to find anything significant. I'm taking it down until one cell trips my BMS UVP at 2.5V

So far I am happy with the cells and happy with the learning process. Happy I haven't made any expensive mistakes.
And I am happy I haven't found anything wrong with my cells other than possibly a little missing capacity. Many people say 1 or 2% of missing capacity is acceptable for these cells. I have thought about it a lot and decided I am ok with that. I can't even consider my tests as proof of anything. But I'm getting used to the BMS, cells and test equipment.

My other 3 batteries will get much less testing. My BMSs will tell me if something is wrong.

 

[Steve_S]

Considering that these 280AH cells cost almost the same as 200AH cells and you can certainly get 250AH out of them with not much effort, they are still a GREAT DEAL, and if you consider that taking 10% off (5% top & bottom) that is 252AH, or for those taking 20% off (10% bottom & top reserved) is 224AH. So "Technically" with a conservative 10% margin you are getting the full deal anyway with 252AH usable.

CATL 202AH = $76,
Lishen 272AH = $73,
EVE 280AH = $80
- 120AH = $36 and 105AH = $35
* Depending on vendor (these are Luyuan prices)

 

[ArthurEld]

Considering that these 280AH cells cost almost the same as 200AH cells and you can certainly get 250AH out of them with not much effort, they are still a GREAT DEAL, and if you consider that taking 10% off (5% top & bottom) that is 252AH, or for those taking 20% off (10% bottom & top reserved) is 224AH. So "Technically" with a conservative 10% margin you are getting the full deal anyway with 252AH usable.

CATL 202AH = $76,
Lishen 272AH = $73,
EVE 280AH = $80
- 120AH = $36 and 105AH = $35
* Depending on vendor (these are Luyuan prices)

I agree Steve. I knew this was a great deal and I haven't been able to find anything wrong.
I tried hard to find something wrong. Deligreen is one of the top sellers and I am confident they would fix any problems to my satisfaction.

Here's a few screen captures I made from my BMS. Still no balancing. I just want to see how the battery pack behaves.
And of course I will get another capacity reading. And see which cell hits 2.5V first.
I have 3.5 days until its done.

 

[ArthurEld]

I am surprised how well the cells stay together. I top balanced the whole battery to 3.65V this time.
Since they diverge so bad up there I was afraid they would move apart when I got out of the knee.
But that is not the case they came together and stayed together. So far my delta value has been .006 and .004.

 

[Gazoo]

The Delta you see is mostly what I have been seeing too although I have noticed a difference of 0.020 at various states of charge while charging and discharging. But they always come back to less than 0.010. I haven't kept very good track of where this happens.

Watch what happens when you get close to 3 volts. That is when mine start to drift. When my lowest cell is 2.5 volts my highest cell is 3.00 volts. If you do better than we can assume your cells are better matched. At the top when fully charged I see a Delta of 0.083. That's nothing considering how fast the voltages go up at the end of the charge. Please keep us updated and let us know what your total capacity is when you finish, and your Delta when the BMS cuts off. Thanks.

 

[ArthurEld]

I plan to post my results Gazoo.

My first screen shot of the BMS is fully charged but I just did a top balance. The delta was .012.
You probably mean after you did a cycle then you had .083 delta.

I would think the divergence wouldn't be as bad at the bottom knee because it isn't so vertical.
Since we top balanced I'm sure they will become unbalanced at the bottom.
My capacity range is probably something like 272Ah to 280Ah so I expect my capacity will be the same as yours.
And as you said, that is 3% out of spec.
If I get something else I will assume the cheap capacity tester wasn't accurate.

My active balancer might give me the full capacity at least in the area it operates. It is supposed to boost the low ones until it gets to full charge.
And it is supposed to add capacity to the low ones on the bottom too.

I'd have to turn on active balance and set my charge and discharge limits to 3.65V and 2.5V to see if I could get the full 280Ah. So many tests!

 

[Gazoo]

You probably mean after you did a cycle then you had .083 delta.

Yes. I don't recall what the Delta was initially. And my cells sat for a couple days before I hooked up the BMS.

My active balancer might give me the full capacity at least in the area it operates. It is supposed to boost the low ones until it gets to full charge.
And it is supposed to add capacity to the low ones on the bottom too.

In the upper area I doubt the balancer will help boost capacity. There is so little voltage difference and the voltages move very quickly in that area of the charge. I set my BMS to balance to 0.015 in the upper area. It only took a couple of hours. And my BMS uses passive balancing. I didn't gain anything.

I don't understand how it can add capacity in the lower area. It's taking current from the high cells and putting it into the lower cells. Also I would be concerned about balancing at the bottom. I think it's possible that's going to screw up the top balancing. I am looking forward to your results to verify.

 

[ArthurEld]

Yes. I don't recall what the Delta was initially. And my cells sat for a couple days before I hooked up the BMS.

In the upper area I doubt the balancer will help boost capacity. There is so little voltage difference and the voltages move very quickly in that area of the charge. I set my BMS to balance to 0.015 in the upper area. It only took a couple of hours. And my BMS uses passive balancing. I didn't gain anything.

I don't understand how it can add capacity in the lower area. It's taking current from the high cells and putting it into the lower cells. Also I would be concerned about balancing at the bottom. I think it's possible that's going to screw up the top balancing. I am looking forward to your results to verify.

I think the active balancer just makes them even so they all hit the limit at the same time. And I think the capacity will be the same as the highest capacity cell. Or close to it.

I will try to do some tests.

But I need an inverter. I don't like wasting so much electricity. And what I am doing is too slow.
I've been avoiding buying a small one because I am getting close to buying a big inverter and I could probably use that to charge my batteries and use the energy when I need to discharge. I should be able to use batteries to charge batteries.

I'll get there someday

 

[ArthurEld]

The active balancer probably won't effect capacity unless the charge discharge limits are close to the BMS limits.