BYD , CATL & Sinopoly , Winston LFE Cells


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Engineer34

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Feb 5, 2020
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At DIY community i am hearing about Sinopoly and Thundersky and Winston etc.

But in key players of LFE we only read about CATL , BYDetc.

I had an old image in my mind Winston is amazing with its Yttrium cathodeetc with unbeatable 2000+cycles etc.

So why we don't hear about those Sinopoly , Thundersky , Winston in top battery producers ?
Are they small scale or are they only famous for DIY or are they old history now ?
 

CUDAcores89

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Dec 30, 2016
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Engineer34 said:
At DIY community i am hearing about Sinopoly and Thundersky and Winston etc.

But in key players of LFE we only read about CATL , BYDetc.

I had an old image in my mind Winston is amazing with its Yttrium cathodeetc with unbeatable 2000+cycles etc.

So why we don't hear about those Sinopoly , Thundersky , Winston in top battery producers ?
Are they small scale or are they only famous for DIY or are they old history now ?
The reaosn we don't hear about them so much is because as you have said - they are a small scale cell producer. I havew only ever seen their cells once, and that was from my local scrap yard. Nobody uses them because they are diffucult to find used, and when they are found used they end up costing more than plain jane 18650 laptop packs.

The DIY powerwall community uses 18650 cells because they are mass produced in the millions, their formula is relaible, and they can be found almost anywhere in the world locally with the right sourcing. The Pirsmatic style lifepo4 cells you are referring to? Not so much.
 

Engineer34

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I was also curious about the economical view of 18650 as well. These prismatic batteries promise like 2000-3000cycles.
But how many cycles can 18650 salvaged from batteries can offer ?

I checked some new 18650 has 500 cycle life, can not imagine salvaged cells cycle life. If so why everybody use 18650 ?
It should be 4 times cheaper then prismatic new cells. Right ? Can anybody give some figures in order me to understand ?
 

OffGridInTheCity

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Dec 15, 2018
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Engineer34 said:
I was also curious about the economical view of 18650 as well. These prismatic batteries promise like 2000-3000cycles.
But how many cycles can 18650 salvaged from batteries can offer ?

I checked some new 18650 has 500 cycle life, can not imagine salvaged cells cycle life. If so why everybody use 18650 ?
It should be 4 times cheaper then prismatic new cells. Right ? Can anybody give some figures in order me to understand ?
18650 (lithium-ion) can definitely last longer than 500days in a solar DIY system... but I agree its a question of how long that is interesting to me.
Here's a thread by @Generic - https://secondlifestorage.com/showthread.php?tid=6868 - whose's cycling some 18650s @ 100% DOD to see what happens - he's reached the 1,200cycle mark recently and a couple of the cells still have 75% of the starting capacity.

There's also the famous Battery University page -https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries - showing that 1,000(s) of cycles are possible at low DOD %(s). My oldest 18650 14s120p battery is now 2yrs old with 603 cycles at average DOD of 44%and going strong. ButI need 7,000 cycles to break even, so it will be a while yet before I have serious data.... :)

One thing about 18650(s) is that they are 'many small units' (as apposed to a prismatics bank that would likely be fewer/larger units) and it might be that as my battery bank ages it will die in groups of cells here and there rather than 1,000(s) of cells all at once - so I may have a chance to extend the life by ongoing cell maintenance... which is why I designed my packs to be serviceable.
 

Generic

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Google "Cycle Test LiFePo4." There's some good information there. One paper by a Czech researcher tested Winston LiFePo4 cells. 100% depth of discharge at C/4 yielded 950 cycles to 80%. The LG and ASO cells I'm testing are also at 100% depth of discharge, and I'm testing at twice the current, C/2, which is stressing the cells more than the LiFePo4 cells in the Czech test. My cells were also about 8 years old at the start of the test. The cells hit around 80% of original capacity after about 1,000 cycles, even though the LG cell was supposed to hit that at 300 cycles according to it's data sheet. There's a bunch of people running laptop cells for 4+ years with minimal degradation. TBH, I'm not really understanding the hype around LiFePo4 cells.
 

Engineer34

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For me i have the opposite image/idea. LifePo4 cells are safe and long life in the genetics.
18650 has short life 250 to 700 cycle. There is Cell Database here.

Also LG and Winston compare is not so logical. LG is premium. You can compare with premium
LFE producers like A123 or Microvast etc. They have premium cells 5000 cycle.

At your tests LG could perform better because of less stress , constant regular charge discharge. So
results surprised you. And other cells disappointed. That does not mean good quality LifePo4 will not do
battery then LG s performance there.Also LG cells are pretty expensive , famous to degrade on high
voltage with impedance (Australian Battery Tests ).

I also have the image if you use LifePo4 in low charge discharge rates 1/6C etc , it almost never loose
balance. So for some applications you can avoid to use BMS. ( Indoor with voltage controlled chargers).
Don't think anybody would dare to do big set ups with 18650 NMC, NCA etc. Right ?
 

Jejochen

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as in my region, Belgium, it is very hard to find free 18650 cells as there are laws here that state every battery must be recycled by a recylcling center that is not allowed to sell or give them away. So, i had to pay anyway for cells, i found it more attractive to pay a bit more and have new lifepo4 cells. They don't explode, are easier to setup (no soldering/welding fuses and busbars,...), and the prismatic cells are easier to store due to their shape. I have 30 kWh system running now for test, it works flawless so i am gonna double my capacity. I can recommend it to everyone. My system is in my house, with my wife and kids, so safety was a primary goal. As the cells don't explode or so, it was an obvious choice. i would only take 18650 cells if i had time to waste, got em for free, and could store them outside my house.
 

Engineer34

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For me i even don't want to go with 18650 again , even i will get them free.
( I support guys here with all my heart that they are giving a second life chance to those
cells before recycling but I don't have that much free time , don't want that NMC risk etc)

Jejochen , do you have photos of your set up ?
Do you wanna share inverter , BMS and also where did you buy those LFE cells ?

I am in Utrecht and i have a friend to get lots of Pouch LFE batteries , but somehow Prismatic
sounds little more safe , rigid etc.
 

Jejochen

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Engineer34 said:
For me i even don't want to go with 18650 again , even i will get them free.
( I support guys here with all my heart that they are giving a second life chance to those
cells before recycling but I don't have that much free time , don't want that NMC risk etc)

Jejochen , do you have photos of your set up ?
Do you wanna share inverter , BMS and also where did you buy those LFE cells ?

I am in Utrecht and i have a friend to get lots of Pouch LFE batteries , but somehow Prismatic
sounds little more safe , rigid etc.

inverters victron multiplus 2 in 3 phase, batrium bms. the wires will be cleaned up a bit more. This was a test for the cells wich performed flawless. the company sells them for 200 Ah, but i tested them at 206 Ah. I gathered some enthousiasts and together we ordered 165 cells wich are on their way as we speak. With my part of 48 cells i will double the capacity, and the cabinet will be full :)


image_qgryjb.jpg


image_eercai.jpg


.
 

Engineer34

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Feb 5, 2020
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How much was those cells cost include delivery etc?
Are you cycling regularly or only for Back up , then
are they good for self discharge and IR ?
 

Jejochen

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These cells costed me about a 4400 dollars (48 cells), but i should check to be exact. The cells are cycled each day with sunpower i have to much, and it is used at night.
The 96 cells are for sale by the way, i want to replace my 200 ah cells with 280 ah cells...
 

Crimp Daddy

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Engineer34 said:
If so why everybody use 18650 ?
It should be 4 times cheaper then prismatic new cells. Right ? Can anybody give some figures in order me to understand ?

Because many people get the cells for free...

I only use 18650 for small projects, like portable power pack.

For anything larger, I use cells from electric cars. They are still substantially cheaper than new LiFePO4 and still have excellent cycle life because we control the DoD/SoC. Couple that with the low power demands when compared to EV, and the cells can last a long time.

There have also been issues with some of the prismatic LiFePO4 suppliers, like CALB. They are known to put out inconsistent product, at least this is what I am told by people who have had experience with it in the past.
 

Engineer34

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Jejochen , can you PM me your cells ?


Crimp Daddy
What kind of EV cells you use that cheaper then LFE ?

Jejochen just mentioned up he bought New cells for less then
USD150kWh. Can you share more about your cells ? Is it safe , what kind of BMS , inverter you use ?
 
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