Ordered 8 EVE "new" 280Ah cells from Shenzhen Luyuan

Pyrofx

Flux capacitor builder
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Jul 27, 2020
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Oatman Az
Im here to tell you . The trucks are coming out all night long. And BNSF is also giving anyone that will come into the yard on Saturday or Saturday a 50 dollar discount on load charge.

This is one of those cases of read what you want , but every other day I drop of and pick up a train. 250 containers in . 350 out.

About 15 itrains n a 24 hour period.

Greg
 

Stepandwolf

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Nov 14, 2020
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Further research indicates that under normal conditions, trucks cannot pick up containers past business hours. They are now planning to allow trucks in the yards 24/7. But, experts say that this is a 'nothingburger' due to the fact that there is no place to deliver the containers in the middle of the night, so it's unlikely many trucks will pick up after hours anyway. :(
Wonder how many are local deliveries vs. long haul? And if they are just hauling them to the railyard, they might be open..
 

Solar Steve

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Well, it took a very long time, but I finally received my 8 "new" 280 Ah EVE cells from Amy at Shenzhen Luyuan. All cells arrived well packed and in excellent mechanical shape, I will now start top balancing and putting together a battery for capacity testing. I am very happy with the company, Amy always gave me a good response in 24 hours or less to any of my questions. If I decide to order more I will start here, they are worth the premium.

Timeline for my shipment was as follows:

Payment cleared with Shenzhen Lyuyan: 7/9/21
Order sent out by Amy, she also sent me pictures of the shipment and a summary of the cell properties: 7/17/21
Received by FedEx in California and tracking number active: 10/11/21
Delivery to my door: 10/15/21

I'm sure the extra shipping time has to do with the current long backlog at the ports.

The only thing I'd like to see improved is a change to the studs welded onto the terminals; as many others have mentioned they really cut down on the contact area. Anyone have comments on how best to deal with this? I'm thinking of adding some aluminum washers with a tight tolerance clearance hole, this will at least get me full available contact to the stud while allowing slotted busbars that can tolerate a bit of misalignment, but of course this adds yet another metal to metal interface.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
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Do not use washers or such, you want direct contact to the terminal with the busbars. Try to not use more than One Ring Terminal on the cells, so if you have a BMS & an external Balancer for instance it's best to not have each wired to separate ring terminals. People do it, it works but sometimes it can create problems.
 

Just John

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Do not use washers or such, you want direct contact to the terminal with the busbars. Try to not use more than One Ring Terminal on the cells, so if you have a BMS & an external Balancer for instance it's best to not have each wired to separate ring terminals. People do it, it works but sometimes it can create problems.
I agree it is best to combine into a single ring terminal for any extra connections. I found this the hard way. Yes, you can get multiple to work, but it is best to combine.
 

Short_Shot

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I don't see the contact area as an issue. I believe the resistance in what is essentially zero distance to be minimal if you have good contact, use a conductive paste and use adequate torque. There are limits to what is an adequate surface area but I think any heat created by this joint will be quickly dissipated and in the end when it comes to conductors our primary concern is heat build up, is it not? I am a proponent of using a separate tapped connection to join the BMS sensing wire to the bus bar to allow the torque of the bus bar nuts to be applied consistently and to allow the serrated nuts to bite the bus bar and not the small ring terminal of the sensing wire.
You can believe it all you want but there are devices which can measure it.

If there's any heat at all (rather, any more heat than the cable itself) then it's a bad connection.
 

MrPhoton

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Apr 19, 2021
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33
Well, it took a very long time, but I finally received my 8 "new" 280 Ah EVE cells from Amy at Shenzhen Luyuan. All cells arrived well packed and in excellent mechanical shape, I will now start top balancing and putting together a battery for capacity testing. I am very happy with the company, Amy always gave me a good response in 24 hours or less to any of my questions. If I decide to order more I will start here, they are worth the premium.

Timeline for my shipment was as follows:

Payment cleared with Shenzhen Lyuyan: 7/9/21
Order sent out by Amy, she also sent me pictures of the shipment and a summary of the cell properties: 7/17/21
Received by FedEx in California and tracking number active: 10/11/21
Delivery to my door: 10/15/21

I'm sure the extra shipping time has to do with the current long backlog at the ports.

The only thing I'd like to see improved is a change to the studs welded onto the terminals; as many others have mentioned they really cut down on the contact area. Anyone have comments on how best to deal with this? I'm thinking of adding some aluminum washers with a tight tolerance clearance hole, this will at least get me full available contact to the stud while allowing slotted busbars that can tolerate a bit of misalignment, but of course this adds yet another metal to metal interface.
Sounds like our Batteries were cousins... having likely shared the same ship.
 

Short_Shot

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So why would you double it by adding another terminal?

Or triple it with yet another.

Unrelated question:
I don't have that tester but can it measure straight dc resistance rather than just the AC impedance?

I really need to get one of them one of these days.
 

Dinky

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Jun 14, 2021
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With my YR1035+ milliohm tester I don't get a different reading on top of the bus bar than I do when testing straight onto the terminal. That is when testing through the cell. When I test between the terminal and the top of the bus bar, I get readings of .01 to .04 milliohms. That is pretty miniscule. I get .06 from one end of the bus bar to the other end when testing on top of the bus bar. I get .10 through the bus bar when testing at the aluminum terminals beneath the bus bar. I'm not concerned about .02 milliohms through this connection. I'm actually pleased with it. I try to test everything because a lot of the information available is mixed with opinion that gets passed around and takes on a mantle of authority.

What are the results that you get? I only tested 8 different connections but the results were consistent. I use carbon conductive past and torque the nuts to 5 NM.

I will test again when I install the new inverter this afternoon and start load testing my solar generator expansion. It may be different then. If it is I will update to this thread.
Ray,
I found your youtube channel and was so happy to have found it. Love the approach you use in your quest for relevance. Thank you so much! I'll be watching all of your content.
Kind Regards,
Steve
 

Solar Steve

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Jun 5, 2021
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Very happy with the matching of cells from Shenzhen Luyuan. I assembled a first pack of 4 cells, added a BMS and started top balancing with a bench supply to charge the pack, using the BMS to cut off when the first cell reached 3.65V. Initial balance as received was very good, as shown by the plots below (second is just a closeup of the knee). After this I connected the cells in parallel for a final balance, this took less than an hour as the cells were only different by a maximum of 2 A-h.

On discharge the difference in on state resistance is negligible. Finishing the capacity test now, but in general these cells look much cleaner and better compared to the generic EVE cells I bought from a local seller on eBay.

1634911512493.png
1634911567539.png
 

Yurtdweller

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USA
According to the sheet Amy sent on cell statistics, mine are all within a very narrow IR reading, and a pretty small range of capacity, with all testing over 280, and charged at 3.296, or thereabouts, at time of shipping. Since I'm off-grid, and currently only have a 100ah LiFePo4 pack, I'm considering configuring my first batch as 12v pack, and charging with my solar up to 3.5, then top balancing. Btw, what test rig generated the graphs? I'm considering getting one of these rigs. I have some friends that want me to build them some packs if mine work out well, and I'd like to really test my builds well, if I plan to sell them. Also, I'm planning to build four packs@12v, with different build methods, and I'd like detailed testing for that reason, too.
 

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Just John

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According to the sheet Amy sent on cell statistics, mine are all within a very narrow IR reading, and a pretty small range of capacity, with all testing over 280, and charged at 3.296, or thereabouts, at time of shipping. Since I'm off-grid, and currently only have a 100ah LiFePo4 pack, I'm considering configuring my first batch as 12v pack, and charging with my solar up to 3.5, then top balancing. Btw, what test rig generated the graphs? I'm considering getting one of these rigs. I have some friends that want me to build them some packs if mine work out well, and I'd like to really test my builds well, if I plan to sell them. Also, I'm planning to build four packs@12v, with different build methods, and I'd like detailed testing for that reason, too.

Tester that will graph (it will charge, discharge, and then you set it to charge up for a top balance):


This is the one Will uses (I haven't tried it, but it will only discharge):

 

Just John

Photon Sorcerer
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Aug 15, 2020
Messages
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According to the sheet Amy sent on cell statistics, mine are all within a very narrow IR reading, and a pretty small range of capacity, with all testing over 280, and charged at 3.296, or thereabouts, at time of shipping. Since I'm off-grid, and currently only have a 100ah LiFePo4 pack, I'm considering configuring my first batch as 12v pack, and charging with my solar up to 3.5, then top balancing. Btw, what test rig generated the graphs? I'm considering getting one of these rigs. I have some friends that want me to build them some packs if mine work out well, and I'd like to really test my builds well, if I plan to sell them. Also, I'm planning to build four packs@12v, with different build methods, and I'd like detailed testing for that reason, too.

Just as any FYI, that cell data she sends is in the Eve production database. In a few months the extra data other than one capacity and IR reading are deleted to save space, so save a copy now.
 

Yurtdweller

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USA
Thanks. I'm thinking of getting the EBC-A20. The off-grid Garage guy uses one.
Tester that will graph (it will charge, discharge, and then you set it to charge up for a top balance):


This is the one Will uses (I haven't tried it, but it will only discharge):

 

Solar Steve

Solar Enthusiast
Joined
Jun 5, 2021
Messages
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According to the sheet Amy sent on cell statistics, mine are all within a very narrow IR reading, and a pretty small range of capacity, with all testing over 280, and charged at 3.296, or thereabouts, at time of shipping. Since I'm off-grid, and currently only have a 100ah LiFePo4 pack, I'm considering configuring my first batch as 12v pack, and charging with my solar up to 3.5, then top balancing. Btw, what test rig generated the graphs? I'm considering getting one of these rigs. I have some friends that want me to build them some packs if mine work out well, and I'd like to really test my builds well, if I plan to sell them. Also, I'm planning to build four packs@12v, with different build methods, and I'd like detailed testing for that reason, too.
I didn't use a battery tester to generate the graphs, just used the JBD BMS to read out cell voltages and then put the data in Excel. Capacity on the first pack came out just as expected, roughly 286Ah as measured by a shunt during discharge testing down to the first cell reaching 2.9V. I thought about buying one of the cell testers but really don't think I would use it enough to justify the purchase.
 

Yurtdweller

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Yes. I'm just geeky enough that I'd just love to have one, for fun. Also, I ordered 8 cells more than I really need, and was thinking of selling the spares off, and thought, I might just get a better price with solid, visible test data. It would probably be enough extra to pay for itself. I just found out there's a LiFePo4 importer less than 40 miles from my home, and would just love to run a side-gig building packs over the winter. I'm in the art festivals biz, and my down time is coming up. Also, bunches of my co-workers would love a nice light power pack for their booth, or rv, or campsite.
 

Yurtdweller

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Just be aware of the limitations. If it meets your needs, then get one. He also uses the EBC-A40L, but what someone else uses is not why I chose test equipment.
Yeah. I'm more interested in testing 12v packs. The 40L won't do that. I'm not buying it because a certain person uses it, so much as I liked the data it was generating, and I like seeing things work before I decide. I can't plunge into a 300+ piece of equipment just for this one build, and curiosity alone, though. The price is doable on the A20. I may be reselling all my build equipment after my build. I travel full-time, and don't have or want to do a storage unit again.
 
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