Just received 68 x EVE 280ah from Shenzhen Luyuan

davelondon

Solar Enthusiast
I just received my shipment of 68 x EVE 280ah cells from Shenzhen Luyuan. I've been dealing with Amy Wan, who has been very helpful throughout the process. Here's the product page. From the factory these cells have flat terminals, so they welded studs on for me and supplied busbars. The cells worked out $114 USD each, and the shipping to the UK was about $2200 USD.

The Alibaba system was confusing at times, with several mystery emails saying the contract had been changed with no other information, however the batteries arrived yesterday, exactly three months after I transferred the funds:

Funds transferred: 2021-03-02
Package arrived in the UK: 2021-06-02

While I was negotiating the Amy, there was a report from another diysolarforum user of poorly packaged cells... I stressed the importance of better packaging, and they've really pulled out all the stops on this shipment. Two cells per box, double cardboard boxes and plenty of foam. Each box is completely covered in clear tape, and plastic corner protections on all the boxes. Magnificent. It's going to take me all day to get them out of the boxes!

I've only opened one box so far, and the cells are immaculate. Totally brand new. Over the next few days I'll be opening all the rest, setting them up in parallel and top-balancing. I'll get back to you with my findings, but I'm not expecting any problems considering the condition of the cells I've opened today.
 

Attachments

  • 27204AF7-57D1-4A0F-9C5C-D9610EB4E1E2.JPG
    27204AF7-57D1-4A0F-9C5C-D9610EB4E1E2.JPG
    1.5 MB · Views: 182
  • BE704429-3692-4419-A1F0-8F3034A67305.JPG
    BE704429-3692-4419-A1F0-8F3034A67305.JPG
    665.3 KB · Views: 164
  • C9CEF578-7B4A-4D2B-8C96-D4A56C373701.JPG
    C9CEF578-7B4A-4D2B-8C96-D4A56C373701.JPG
    675.9 KB · Views: 184
  • D1B07464-AC85-4B9F-83E9-BBC0C7FCF04B.JPG
    D1B07464-AC85-4B9F-83E9-BBC0C7FCF04B.JPG
    675.3 KB · Views: 192
  • E35FB3D9-41F5-473D-8E61-F221BDA6F9B6.JPG
    E35FB3D9-41F5-473D-8E61-F221BDA6F9B6.JPG
    843.5 KB · Views: 195

squowse

Solar Enthusiast
Shame about the reduced contact area on the terminals. I suppose if it's the same size or bigger than the busbar/cable lug then it makes no difference?
 

Just John

Photon Sorcerer
I just received my shipment of 68 x EVE 280ah cells from Shenzhen Luyuan. I've been dealing with Amy Wan, who has been very helpful throughout the process. Here's the product page. From the factory these cells have flat terminals, so they welded studs on for me and supplied busbars. The cells worked out $114 USD each, and the shipping to the UK was about $2200 USD.

The Alibaba system was confusing at times, with several mystery emails saying the contract had been changed with no other information, however the batteries arrived yesterday, exactly three months after I transferred the funds:

Funds transferred: 2021-03-02
Package arrived in the UK: 2021-06-02

While I was negotiating the Amy, there was a report from another diysolarforum user of poorly packaged cells... I stressed the importance of better packaging, and they've really pulled out all the stops on this shipment. Two cells per box, double cardboard boxes and plenty of foam. Each box is completely covered in clear tape, and plastic corner protections on all the boxes. Magnificent. It's going to take me all day to get them out of the boxes!

I've only opened one box so far, and the cells are immaculate. Totally brand new. Over the next few days I'll be opening all the rest, setting them up in parallel and top-balancing. I'll get back to you with my findings, but I'm not expecting any problems considering the condition of the cells I've opened today.
Those are the grade A cells, did you get the test reports with those? I know a few months back she couldn't get them, now she sends you a website with a login and password and you can pull the factory test reports.

Those are packaged better than the ones I bought from her last year, but that was also before she started her own company. Amy has worked hard for her reputation.
 

davelondon

Solar Enthusiast
Yes, expensive shipping to the UK is frustrating. Didn't receive any test reports with the cells.

I've unpacked 32 of the cells and they're all equally immaculate. All cells were 3.295 or 3.296 volts. They only included 1 bus bar per cell, which is not enough to connect them all in parallel, so I'm going to top balance them in two groups of 32 cells. Currently charging at 7 amps with a cheap 10A desktop charger.

B5C264CA-590E-4D3E-BE65-B51829AB9EEB.JPG
 

squowse

Solar Enthusiast
Wow - that'll take a while. I was expecting double busbars as well but i didn't mention it so can't really complain.
 

davelondon

Solar Enthusiast
Yeah I have none of the other electrical kit yet so happy to have them too balancing for a few weeks.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
10 hours per cell from 3.2 to 3.65 Saturation and that is with my Tekpower TP1540E that put out 40A.
I started Top Charging the cells in lots of 4 to 3.65, then top balanced as a string of 8 (I run 24V) to full saturation (meaning taking <1.5A), then allowed to settle in Parallel for 3 days and then re Top Balance and allowed to settle before assembly.
 

mrzed001

Voice of reason
Yeah I have none of the other electrical kit yet so happy to have them too balancing for a few weeks.

Maybe you should set it to 3,5-3,55V
The cells are in different %
All charging the same, some will be full way before other.
And that cells do not like if you float them in 3,65V.
The best balance method is 3 steps: 3,45V - 3,55V - 3,65V
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
BTW: I run 24V/1190AH/30.1kWh of LFP, 3x280AH + 1x350AH in one battery bank.
Using Midnite Solar Classic-200 SCC, Samlex EVO 4024 Inverter/Charger.
After a LOT of testing including Hard Thrash tests I've worked out a charge profile that works very well.
As I am 24V, ÷ by 2 for 12V or X2 for 48V.

Profile on my Classic and identical on Inverter/Charger.
Absorb: 28.2 for 15 minutes
Equalize: OFF
Float 27.9V
MIn Volts: 22.0 Max Volts: 28.7
Rebulk Voltage: 27.7
End Amps: 14A (calculated as 0.05 of C-Rate to largest pack. 280AH X 0.05 = 14A.)

This get's the bank charged to full with high amps (Constant Current) and then float (Constant Voltage) tops off so the cells are on average between 3.475-3.500. I am running 7/24/365 so float is used up by the Inverter + provides whatever the packs will take to top off.

NOTE: ALL LFP cells will NOT stay at 3.6x Volts, regardless of how long you charge to that point and how deeply you saturate the cells. They will ALWAYS settle to 3.5-3.55 within an hour or so after charging is terminated. The Nominal Voltage is 3.200 and the primary voltage curve is 3.000-3.450 Above or Below that range is only about 8% of the total pack capacity and NOT significant. In fact this is the normal area we reserve for longevity & max cycles anyway.

See this chart (also in my Signature)
lfp-voltage-chart-jpg.27632
 

davelondon

Solar Enthusiast
I finished unpacking all the cells. All were in perfect condition and 3.296V.

Probably a good idea to top balance in stages, so the first batch aren't left fully charged for weeks.
 

davelondon

Solar Enthusiast
One slightly worrying thing is that this power supply doesn't lock onto a specific voltage... it wanders around seemingly pretty randomly... I've been watching it for a couple of hours, and it's got ~0.05V away from what I set... both upwards and downwards.

I'm planning on leaving this setup for several days at a time, and I'm not certain that it won't wander up over 3.65V... Hmmm... Are they all like that? Or do the better PSUs lock solid onto a specific voltage?
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
All power supplies with CC/CV Constant Current/Constant Voltage will float as the process continues.
Typically the wires are on the Thin side and the alligator clips are EVIL (line losses). Usually we suggest upgrading the wire leads and replace those dumb clips with proper Ring Terminals.
A TRICK: Often it is easier to set the power before connecting the cells. Set it, & verify it is at < 3.650V with a good DMM/DVOM, then connect it to the cell string (with the charger OFF).
Some higher-end chargers actually have a Voltage Sense lead separate from the charge leads to read the voltage at the "end of the wire" rather than at the back of the charger which can be derated due to wire inefficiency or poor sizing.

When charging the PS will display what it thinks is the current Voltage & Amperage going into the cells. The voltage will take a LONG time to change as it goes up but it will, this is the Ultimate Patience Test on a person ! As the charge in the cells increase you will see it eventually. The more cells in the series being charged the longer & more painful it will be to wait & watch. Long Movies & Popcorn are in order while you wait.

Stored @ Charge:
That is OKAY as they will NOT remain static in any case, the cells will naturally & slowly discharge over time. I've tested this in various ways, it takes about 3 months to go from 3.500 to 3.330 Volts, done this with 2 full sets of cells and this is within factory spec. Once they are Top Charged (All cells to 3.6v and saturated) they can sit and discharge naturally while you do the rest without issues. Once you have Top Charged all the cells, then set them in parallel and Top Balance, allow to settle in Parallel for a couple of days, then redo it again (it will be much quicker, believe it or not) and then your ready to assemble your full packs.

Remember that when assembling your battery packs, to bind the cells together.
When Top Charging & Top Balancing, it is RECOMMENDED to place the cells into a Clamp to prevent any possible expansion during charge.
* These LFP cells DO expand & contract a bit during charge & discharge, this is NORMAL but must be addressed as over time if not clamped together there can be cumulative damage.

IF you intend to store LFP cells for a long time, do as the Manufacturers do and that is to store them at 50% SOC or 3.200V per cell and keep them at comfortable temps and they'll last ages.
 

davelondon

Solar Enthusiast
Yeah I'm planning to clamp them together in their final configuration, but not when I'm top balancing them... I figured because they are being charged very slowly, the expansion will be minimal? hmm
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Lessons Learned have been shared.
Horses can choose to drink or not, it's entirely up to them.
 

ghostwriter66

"Here - Hold my Beer"
Yeah I'm planning to clamp them together in their final configuration, but not when I'm top balancing them... I figured because they are being charged very slowly, the expansion will be minimal? hmm
when you clamp them I personally recommend doing it at the 50% mark - to me that seems to be the proper space -- not too tight if its full and not too loose when its empty .... probably some PHD paper out there that agrees with this but seems to make sense in my mind ...
 

GSXR1000

Solar Addict
Shame about the reduced contact area on the terminals. I suppose if it's the same size or bigger than the busbar/cable lug then it makes no difference?
with a pack that large.. the current per cell will be small I bet. especially if 48v
 
Top