Chinese LFP cell manufacturers

[fafrd]

I picked up 8 90Ah LFP cells through AliExpress and got them wired up with an 8S LFP BMS to successfully make a 24V LFP Battery.

I got lucky - this was all before I discovered this site and the wealth of advice and expertise available here.

I’m now planning to build several 8S 280Ah LFP batteries using the 280Ah cells and am considering to purchase through Alibaba using the vendors recommended on this site rather than through AliExpress again.

I’ve seen Xuba and Haomi mentioned as two vendors from which members here have had good experience with but I am trying to understand the relationships before reaching out to them.

Am I correct that both Xuba and Haomi are ‘Trading Companies’ that do not manufacture these cells but rather purchase them in bulk from the manufacturer and then test, sort, and match them before selling in smaller quantities to individuals like us?

I understand that they may also do other light manufacturing such as tapping the aluminum screw posts, but I’m talking about manufacturing of the aluminum-sheathed LFP cell itself.

I’ve seen a few references to ‘EVE’ and datasheets for the ‘EVE LF280’ - is EVE the manufacturer of these 289Ah LFP cells distributed by Xuba and Haomi? If so, do we know whether Xuba and Haomi purchase direct from EVE or through a 3rd-party / broker?

If EVE is the manufaxturer of these 280Ah LFP cells, is there any way to purchase directly from them or do they limit their sales to large MOQ?

The 90Ah cells I purchased through AliExpress look identical to the LF105 pictured on EVE’s website but without any marking (save a QR code). I suspect they are EVE LF90 cells and am trying to understand whether there are multiple manufacturers making identical cells to these or merely multiple ‘trading companies’ reselling these EVE cells in small quantities.

It seems like purchasing through Xuba or Haomi is a safe way to navigate the mysteries of Alibaba and avoid the risk of ending up with B-Grade cells (using the advice from this board) but I’m still trying to understand the relationships back to the underlying manufacturer before deciding which way to go.

To the experts on this board who occasionally pop up with manufacturers datasheets or confident statements about which manufacturers are behind various cells pictured in a post:

1/ which is the recommended manufacturer to purchase the $70-80 280Ah LFP cells? EVE?

2/ what is the recommended channel to purchase small quantities (6-36 cells) of these cells to have confidence they will be Grade A and properly tested to spec, matched, and shipped?

I was willing to risk $360 on the 8 90Ah cells I purchased through AliExpress. They were very well packaged, within 1mV of each other, and while I have not yet performed a full discharge cycle test, I suspect they will prove to deliver close to the 90Ah promised.

Risking $400 just to learn is one thing, but before committing $1000s to new 14kWh and 28kWh batteries, I want to understand the relationships and the manufacturing flow...

 

[Steve_S]

XUBA & LUYAN are partnered Trading Companies. You will not deal directly with manufacturers unless you are buying large quantities (in the thousands). EVE is one of several companies and they are a fairly good company which has been around quite some time. A large portion of our membership has purchased from XUBA & LUYAN through our Rockstar Rep, Amy who really goes the distance.

At the prices we are getting these cells at, they are a good deal BUT they are Voltage Matched but not IR (Internal Resistance) matched by the cell. This is a long & arduous process which is actually quite costly, that is reflected in the pricing (usually doubles it). That having been said, the vast majority of the cells come in quite close to each other and perform within specs.

A POINT LOST ON MANY.
I'm gonna put this right here & upfront. Some people do not agree or like it but it is what it is. Keep in mind that these are Large Capacity cells, in the hundreds of amp-hours per cell. because of the size/volume/capacity these cells will drift at least 1% to 2% during their operational cycles which is normal. Even Li-IOn NMC 18650 will drift & fluctuate to an extent but their cell capacity is in mAh and so individually it's quite small. With smaller cells, it's easier to parallel cells into a pack due to the median average but when going Big Cell this becomes impractical because there is too much variability.

I started one of the big threads on XUBA, my experience & many others has been posted there. 99.5% people are happy and satisfied - there are always a couple who will never be happy regardless... maybe that is what makes them happy, to be unhappy... I dunno.

My recommendation: Build straight simple 24V/8S packs, each with an 8S BMS capable of handling the max load potential being called from your Inverter and properly parallel the packs into your bank to enable proper load & charge sharing. Excellent Doc on properly wiring your battery packs to a bank. https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf Remember that each pack should get a fuse as well.

NOTES on BMS'.
There are many to choose from depending on your "needs" and wants and how you want to setup your system. When you have multiple packs with BMS', the Inverter & SCC ( Solar Charge Controller) will have to be programmed to cutoff Charge / Discharge to the battery bank. This is the tricky part due to the variable ways Inverters & SCC's can be programmed to do things, so much depends on what equipment you have and what it is capable of doing & managing. Some folks want the BMS to tell the Inverter or SCC to cutoff when required and that is possible with some hardware but not all, this becomes even more quirky / problematic if there are multiple BMS's because one does not know what the other BMS' status is for their packs.. In a multiple BMS scenario, the typical configuration is that the battery packs are treated as independent and controls for cutoff are left to he Inverter/Charger & SCC with the BMS' doing their jobs "guarding" their cells on their own.

XUBA STORE: https://szxuba.en.alibaba.com/productgrouplist-815258587/Lithium_Battery.html
LUYUAN Store: https://szluyuan.en.alibaba.com/?spm=a2756.trade-order-list.0.0.110d76e9kv6ApB

Hope that helps, Good Luck.

 

[fafrd]

XUBA & LUYAN are partnered Trading Companies. You will not deal directly with manufacturers unless you are buying large quantities (in the thousands). EVE is one of several companies and they are a fairly good company which has been around quite some time. A large portion of our membership has purchased from XUBA & LUYAN through our Rockstar Rep, Amy who really goes the distance.

I believe I found an EVE store on Alibaba which will sell down to MOQ of 1. The point is that the cost per cell is over $200, ~3X the price of these 280Ah cells available through ‘Trading Companies’ such as Xuba.

At the prices we are getting these cells at, they are a good deal BUT they are Voltage Matched but not IR (Internal Resistance) matched by the cell. This is a long & arduous process which is actually quite costly, that is reflected in the pricing (usually doubles it). That having been said, the vast majority of the cells come in quite close to each other and perform within specs.

A POINT LOST ON MANY.
I'm gonna put this right here & upfront. Some people do not agree or like it but it is what it is. Keep in mind that these are Large Capacity cells, in the hundreds of amp-hours per cell. because of the size/volume/capacity these cells will drift at least 1% to 2% during their operational cycles which is normal. Even Li-IOn NMC 18650 will drift & fluctuate to an extent but their cell capacity is in mAh and so individually it's quite small. With smaller cells, it's easier to parallel cells into a pack due to the median average but when going Big Cell this becomes impractical because there is too much variability.

The 8S BMS I have used does not offer any monitoring, but I’m thinking of adding an 8S monitor precisely to keep an eye on drift and matching over time / with use.

I’m not crazy about the idea of burning power on a monitor for the 99.9% of the time it is not being used, so would ideally like a 9-pin cable on each of my 8S batteries that can be connected to the 8S monitor only when I want to check the battery.

I’ve also seen some wireless 8S monitors which would allow the battery to be monitored remotely like I monitor my solar panels.

Do most DIYers here include a way to mi itor thrir cells/batteries and it there a recommended supplier/product for either plug-in as-needed monitoring or wireless monitoring?

I started one of the big threads on XUBA, my experience & many others has been posted there. 99.5% people are happy and satisfied - there are always a couple who will never be happy regardless... maybe that is what makes them happy, to be unhappy... I dunno.

My recommendation: Build straight simple 24V/8S packs, each with an 8S BMS capable of handling the max load potential being called from your Inverter and properly parallel the packs into your bank to enable proper load & charge sharing. Excellent Doc on properly wiring your battery packs to a bank. https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf Remember that each pack should get a fuse as well.

NOTES on BMS'.
There are many to choose from depending on your "needs" and wants and how you want to setup your system. When you have multiple packs with BMS', the Inverter & SCC ( Solar Charge Controller) will have to be programmed to cutoff Charge / Discharge to the battery bank. This is the tricky part due to the variable ways Inverters & SCC's can be programmed to do things, so much depends on what equipment you have and what it is capable of doing & managing. Some folks want the BMS to tell the Inverter or SCC to cutoff when required and that is possible with some hardware but not all, this becomes even more quirky / problematic if there are multiple BMS's because one does not know what the other BMS' status is for their packs.. In a multiple BMS scenario, the typical configuration is that the battery packs are treated as independent and controls for cutoff are left to he Inverter/Charger & SCC with the BMS' doing their jobs "guarding" their cells on their own.

XUBA STORE: https://szxuba.en.alibaba.com/productgrouplist-815258587/Lithium_Battery.html
LUYUAN Store: https://szluyuan.en.alibaba.com/?spm=a2756.trade-order-list.0.0.110d76e9kv6ApB

Hope that helps, Good Luck.

Yes, that is exactly my plan (multiple 24V 8S batteries connected in parallel, each with their own BMS).

I’m relying on my MPPT/SCC to protect against overcharging and the low-voltage cut-off of my inverter to protect against overdischarge, so BMS is there primarily for balancing as well as fail-safe against shorts or other failures.

I’ve read the threads about the possibility of damaging MPPT controllers (arcing?) when the BMS abruptly cuts off charging (from a failing cell that is overcharged, for example) but it seems to me that this should never be possible with more than one battery in parallel.

Even if a cell in one battery fails and that BMSs overcharge protection kicks in, that just means all of the SCCs current will be directed to the second battery and the SCC should be fine.

I’m prepared to take the risk that I will not have two batteries fail from bad cells before I notice the first failure and would prefer to invest in a second battery rather than investing in high-current switches, control electrinics and wiring, etc...

Is this understanding correct? If I am relying on MPPT/SCC to control charge cut-off, will having two batteries in parallel essentially mean that I don’t need to really be bothered about additional protection for the SCC?