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LTO "Grade A" Aliexpress Cells

Hello,

I want to share my YinLong LTO cells experiences here since I might be useful to anyone:

1) First it is important to know that Yinlong is owned by BYD which is an electrial vehicle producer. BYD is the one of biggest electric vehicle company world-wide beside Tesla. This year Tesla could sell more vehicles, but until 2019 BYD was world-wide #1 producer.

2) All Yinlong cells are used. No "brand new" cells exists! All new Yinlong cells are used for multiple years (up to 10 years) within electric vehicles like buses. Since the high c-rate of 10C you can load for example buses quickly at (end-)stations. Also, break/acceleration power of the buses is put on the LTO cells. From my opinion and what I have researched, you will never get/buy a complete new LTO cell from Yinlong. But for solar storage you do not need 10C at all. Please notice, I never was able to do a 10C test, but I do see my LTO cells have a higher impedance, but this is not a problem for me at all. Image of one aliexpress seller:
View attachment 30435

3) Once the impedance of the LTO cells within the electric vehicles are getting to high, the cells are removed from the electric vehicles and get rewrapped with the blue heatshrink design we know from Yinlong LTO cell. Under the heatshrink - and while used in electric vehicles - the cells looks as follows (images not from myself, found on the net):
View attachment 30427View attachment 30426

4) The capacity and impedance of the used cells is checked and this results how the are labelled/wrapped. Therefore, we do have 30/35/40/45 ah in 66160 format. By the way, within the past Yinlong also produced 55ah LTO cells in 66260 format, but they are not build anymore. We do have different cell grades: A/A-/B/C. Once a seller have posted an image about the cell grade for 40ah cells:
View attachment 30428
I can confirm on my orders (40ah only) on aliexpress, the cells are categorized with this parameters.

5) If built a 6s5p bank and have ordered 36 LTO cells at aliexpress. I have done three different orders to different times. From my experience I have gotten the most weak cells on special actions like "Single days" or "Black Friday" sales. Usually, you buy packs of 6 cells (6,12,18,24,30,36, etc) and from my experiences so far (get a lot more cells the next days...): From 6 cells, 5 cells are as promised (for example over 40ah) and at least 1 cells is way too low. I have checked/tested every single cell and listed them as follows:

View attachment 30431
View attachment 30430

The first order (#1-#12) was not on a sale and they are pretty average. The second order (#13-#24) was a "Black Friday" sale on the cells are bad quality (4 cells below 40ah). Then I complained about the cells and the seller send me the third order (#25-#36) for the halve price. While other orders are mixed in cell grades, the third order was all "Grade A" cells.

Capacity test parameters: Load to 2,6V, Cuttof at 0,5A - Unload to 1,9V, 8 Ampere discharge / This means there is some little unleft capacity which should not matter.

6) The weight of each cell is important, BUT also light weight cells can offer the capacity. I do think, they sellers at aliexpress do not know much about the cell quality they are selling. I do think the packs are packed by weight. My packs of 6 cells are all 7,175kg and 7,295kg - no matter which grade. Additionally, I do not think the sellers have the time to test the capacity of each cell there are selling. But I must add, that one ordered box someone noted by hand ">38"...

7) The cells can be balanced all ways. I have bottom-balance them, top-balance them and they are quite stable. However, due the different impedance of each cell, over (long time) they will drift. From my experience the cell drift is small, even due the different impedances. Currently, I am using an QBBM active balancer and I am quite happy with it, just works.

8) Discharge efficiency is good! Nothing to worry about. Also self-discharge is nothing to worry about.

9) The cells are very robust. I have revived cells with 0,5V or lower with full capacity. They are working on my bank as this never happens. They are happy within a very wide temperature range.

10) My usage range of these cells is between 2,0V - 2,5V. It is possible to use a higher range, but this works very stable and accurate for me and I got more than 85% of the capacity.

11) One of the most annoying things are the aluminium screw threads. Be aware if you use any sort of loctite, it might be possible you will never ever getting be able to untighten the screw anymore. Even without loctite etc., some you will destroy the screw thread on thighting. I have lost one cell since I was not be able to remove the screw anymore.

12) You can build quite cool - no amazing battery packs with Yinlong LTO cells - but from my opinion you need to check every single cells capacity and loading behavior. I can remember a cell which was really hard used and have bumpy charge/discharge curves, instead of the usual smooth ones.

13) Never buy cells from GTK manufacturer. While I never ordered ones, there capacity seems all to be lower as promised. Also, they are way cheaper then Yinlong cells. I would advice to avoid them!

14) I do not have evidences that the cells are all used. Surely, no one will tell you this, every seller only sell "brand new" Grade A++ cells. But it seems so obvious that these cells are used and rewrapped!

15) I do like them, I am really happy with them. Works perfectly for me on 12V, as on 24V. While this only based on my own opinion I hope this information is helpful for anyone!

Bye
Tobi
I just saw this post and I agree with moth things he said. the one thing to point out is that he said he has "revived cells " from .5v this should be true and is only these cells can be 100% discharged without damage. This is a huge benefit if you have a remote system that could go down.

The threads are very fragile. One batch sent me nuts and I used those nuts but ruined 4 cells because the milling was not good on the nuts and they bound up. once this happenes the terminal gets ruined. I never had a binding problem with nuts purchased here at the hardware store. I did have a binding problem once when i drilled and tapped my own connector.

I buy nothing from ali express only alibaba directly and have found that a good dealer will provide similar full capacity cells.

I do no active balancing but allow the chargery to stop charging once any cell reaches 2.65v. I have used this method for about 3 months and the difference runs about 35mv between 12 cells in series.
 
It is possible that EVE cells are about 290Ah-300Ah from the factory.
And after 2 or 3 years of use they are in the 270Ah-280Ah range.
Speculating of course.
The worst thing about that theory is that it would mean the cute Chinese girls were lying to me.
 
What makes you trust OSN or Kokpower? Or maybe a better question, how did you first come to trust them before you had experience with them?
Hello. I looked at the number of years they were in business and the quality of detail of the web page and the pictures. If there was any discrepancy of thread quality or stated capacity differences in the page, I crossed off them off from buying them. Then I give them a test buy. If the batteries don't measure up on appearance , capacity, thread quality, resistance , and internal shorts, I would not use them again. I have been buying LTOs for @ 7 years . My first buy of Yinlong cells of 6 pcs were 30ah re wraps and 2 pcs had shorts that dropped .5v over two months. Tested them (played with) for about 2 years . I used 5% phosphorous copper to connect them , thinking that copper is good , Not , phosphorus copper is less than aluminum.

My background is 49 years in the machine shop area , Building computers since the 286's and overall battery nut since the age of 5 , James Bond Battery car.
 
I would be very interested if anyone finds true grade A 45ah cells. I'm looking to buy some for an ebike project.

It would be nice to know if these are truly all heavily used cells. Is it possible the 45 ah cells are the real deal, or are even they used? If that's the case i wonder that the original capacity is before they go into buses, 50ah+? It's frustrating not being able to find a reliable source for actual brand new LTO, from any manufacturer.

I guess this is their official website? As you can see they list 35, 40, and 45 ah cylindrical cells. Not sure if that helps explain anything.
 
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What are you test parameters to identify "used" cells and to measure 40+ Ah ?

I have a bunch of 50 cells here and they all are clearly above 40 Ah (up to 43) ... I do my tests between 1.6 and 2.75 Volt and discharge with 10 A.
Is that representative ?
 
I've got 6 orders with them all LTO based packs. I have had zero trouble with LTO based packs and GTK.
 
Wonder if anyone in the forum actually get the real grade A 45AH cells before? There is a lot different generation of Yinlong LTO cells out there.
45AH <= 1.25kg
40AH <= 1.22kg
I orderd from Aliexpress store "oye Store" and at first I got grade B cells (2016), rated for 12Nm...and torquing them down with 12Nm, one stud came off the cell...then I got a replacement cell. The new cell (2019) is rated for 7Nm...seems like they figured, that 12Nm is too much. Also, everything is written in red color on the new cells positive pole. The new cell actually pulled 45Ah...very impressive. But it also has been used before (scratches on the terminals).

Do never buy LTO cells from Shenzhen Yidong Technology Co., Ltd. from Alibaba. They ship grade B cells and do not refund you and claim, that everything is alright. I bought 132 cells for USD 5570.60 and 7 cells had a high internal resistance / impedance of 1mΩ to 10mΩ. Half of the cells arrived with less then 0.5V. People of trade assurance do not understand the graphs and the tests...they require a 3d party inspection by TÜV Reinland in Shenzhen....and guess who pays for that.
 

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I have the same issue with my LTO cells i have 110 40ah grade b LTO cell in two strings of 55.
from 2.18v/cell to 2.50volt per cell I have 23.5 Ah from 40 rated, but it not lost capacity after 2Mwh of energy passed troug them (110 cells) i know from some time the story about used and re wrapped cells.
Perhaps new cells are too expansive.
Some how it make me turn my attention on a larger capacity LFP bank.
 

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Quality controll
When purchasing those cells, it is good to have a meter to measure the impedance / internal resistance of those cells.
If the impedance is below 0.5mΩ or at least below 1mΩ, you should be good to go. You could get such a meter to measure the internal resistance:

Report: 40Ah grade B cells 66160H
I wrote a report about those LTO cells with high internal resistance (see attachment). And I also compare them with a grade A 40Ah LTO cell. Furthermore, you can find the Yinlong datasheets with all technical information of the 40Ah LTO cells.

Balancer
You could use such a programmable Active balancer, that you can set to balance above a voltage of 2.45V/cell:
They have a bug in the software...so it balances all the damn time...so you have to switch the B+ wire on at a voltage over 2.4/cell...that is annoying, but shunts like the Victron BMV-700 can do that. With the BMV-700, you can also switch active balancing on at a high SOC.
IMG_20211025_231935.jpg

Battery pack
I also use 110 grade B 40Ah LTO cells in a 22S 5P configuration with 50.6V nominal pack voltage.

40Ah LTO 22S 5P.jpg

BMS
As Battery Management System I use the 250A version of the 22S LTO BMS:
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Usable Voltage range
You can use those cells from 2.9V to 1.5V to get the maximum out of them. But you should not absorb at 2.9V...so for most applications, it is best to use 2.5V to 2.6V as a end of charge voltage.
And for end of discharge voltage, 1.6V to 1.8V should do the job and you can still get about 99% or 98% of the capacity at 1C discharge rate (40A).
 

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The only person I know who had found a reliable source of good LTO cells was Craig .... and he seems to have abandoned this forum for some reason. His name is no longer available to tag.

He sells LTO cells on Ebay, but I don't know what his name is on there.
 
Hello,
I searched through the forum for the AliExpress / Alibaba sellers that most probably sells true grade A and new (not re-labelled) YinLong 45Ah 66160 cells... and I found this thread :).

Can we trust OSN Power and/or KOK Power (KOK's Alibaba)?
Do you know other AliExpress / Alibaba sellers that truly sells 45Ah YL cells with internal impedance <= 0.5mΩ or <= 1mΩ?
A word of warning about your question, there are many smart and informed people on this forum, but at the same time there is a ton of misinfo on this forum about grade A cells, many people accept what sellers or other forum members say uncritically, and many people are predisposed to wanting to believe that the cells they bought are grade A. Beyond that, its a hard thing for consumers to know with any certainty when buying off the grey market. So if you do get recommendations, still do your own due diligence, and remember that price is one of the best indicators. That said,

I've heard GWL, which is an EU based company I believe, sells grade A, LTO cells, but I'm not sure if they ship outside of the EU and if they do what the cost would be. I believe this company has a good reputation and has been around for a while, but I don't have personal experience or any depth of knowledge about them. Here is the link
 
Hello,
I searched through the forum for the AliExpress / Alibaba sellers that most probably sells true grade A and new (not re-labelled) YinLong 45Ah 66160 cells... and I found this thread :).

Can we trust OSN Power and/or KOK Power (KOK's Alibaba)?
Do you know other AliExpress / Alibaba sellers that truly sells 45Ah YL cells with internal impedance <= 0.5mΩ or <= 1mΩ?
Yes, in Europe, GWL delivers good quality...I have good experiences with them. But the prices are high.

I am in contact with Mrs. Luz Zhang from Yinlong Energy Co., Ltd.:
They produce LTO cells since 2009 and you can get grade A cells.

Right now they offer 40Ah and 45.5Ah LTO cells with the 66160 form factor.
She also told me, that they intend to produce 50Ah cells in future.
 
For solar system pouch LTO is enough or even prismatic, LTO is far more better than other lithium but is expansive.
I am interested what capacity is between 2.18 to 2.50 for a 40 ah 66160 LTO Yinlong cell, I found 23ah for my grade b cells.
 
For solar system pouch LTO is enough or even prismatic, LTO is far more better than other lithium but is expansive.
I am interested what capacity is between 2.18 to 2.50 for a 40 ah 66160 LTO Yinlong cell, I found 23ah for my grade b cells.
With a 5A discharge per cell, you should get about 65% of the capacity.
[5A discharge is 0.125C or C/8]

With a 40A discharge per cell, you should get about 50% of the capacity.
[40A discharge is 1C or C/1]

But be aware, that the result is highly dependent on your internal resistance. If the internal resistance is high, you get less out of the cells.
Why do you only want to go down to 2.18V/cell?

So yes...I can absolutely reproduce your 23Ah result from 2.5V to 2.18V discharge.
 
I have an order with Yinlong on Alibaba. I'll let you guys know how it goes. It's not cheap compared to lfp, but the temp and c ratings are crazy.

BTW I got like 4 different versions of the spec sheet with different pulse/10 second ratings for the 66160h 40ah cells. Anywhere from 400 to 800.

Also, battery hookup has some lto cells right now.
 
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