Greetings: Just checking to see if the EVE cells arrived and what you think of them. I too am interested in these cells but am a little leery about buying anything until whatever happens in Jan after the WH power change, or not, blows over. Who knows what will happen and if having an extra 5k on hand will be needed, or not.
Steve, I thought EVE cells were exclusively made in China, but a quick internet search revealed this: Home (evebatteryusa.com)Let me put this as plainly, clearly & simply as possible, translation issues considered.
NONE of the EVE, Lishen cells being sold as "Storage"or "ESS" or anything like that at these price points are MATCHED or even BATCHED.
NONE !
Vendors sort them by Voltage (typically 2.99 to 3.20 voltage - storage & shipping voltage) so that matches up. Then they double check with a YR1030 or YR1035 to see if the standing IR (Internal Resistance) is the same. They in turn CALL THAT MATCHED !
They will NOT match up during Charge or Discharge. They will deviate above 3.40V and below 3.10V without manually conditioning the cells by Bottom & Top Balancing. Top Balancing CAN improve the top side some but not the low side. This is a very marginal gain.
You will get "RUNNERS". These are cells with variable IR. They will either RUN to 2.50V Fast from around 3.10V while the others are above 3.1V or RUN to 3.65V from 3.40V while the others are still at 3,850 and above. These Runners LIMIT the total battery pack capacity as they will force Low Volt Disconnect or High Volt Disconnect cutoff before the other cells reach that point. These are runners because they transition FAST. The "Runners" appear to be roughly 10% of cells sold. * Runners can be batched together (as a pack) if they match Top & Bottom giving a reasonable return, but it will be the "oddball" with tricky edges.
280AH cells can deviate as much as 280mv, or 1mv per AH capacity, either at the top or bottom. This seems to hold true to other sizes as well.
Manual Conditioning & preparation is ESSENTIAL for these COMMODITY CELLS. That is Bottom & Top Balancing.
Failure to do so, will not realize the full potential of the assembly.
* Nota Bene * This will also result in havoc with SOC reading accuracy if not done.
Premium EV Grade, Grade-A Cells will cost 2X just to start PLUS cost of Matching & Batching which can easily add $50+ per cell to the cost.
Fortunately: LFP optimal voltage if 3.2V per cell. The cells "as is" function well between 3.180 to 3.400 +/-. This is actually the primary curve for the chemistry.
- Below 3.00V is pointless, it is the end of the curve and only represents <5% of the AH Capacity.
- Above 3.50V is also only about 5% of actual capacity, Charge LFP to 3.65V till amps taken = 1A, within an hour the cell will settle between 3.55 to 3.50, this is NORMAL
- Most folks, to ensure Long Lifespan & Cycle Life generally reserve off the top above 3.5 and below 3.0 anyways.
The ONLY way to verify IR and to manually test, sort & batch them is a process. An IR Tester such as this (the OEM, not a relabelled VAR) Real Four Wire Lithium Battery Internal Resistance Tester YR1035+ Nickel Hydrogen Lead Button Polymer Alkalinity|Battery Testers| - AliExpress is required. * Also available on EBay/Amazon, beware of knock offs, many are rebranded by VARS (value added resellers), Yoarea IS the OEM. (original equipment manufacturer)
Pre-Balancing Cells | Orion Li-Ion Battery Management System
High resistance cell | Orion Li-Ion Battery Management System
AN FYI EXAMPLE: Custom Job for matching cells (batteryspace.com) It is not a joke ! Matching & Batching = $$ due to time & resources required. Gear for doing large batches cost as much as a house !
When discharging/charging cells for top/bottom balancing and after assembly, remember to "FIX" or "Clamp" the cells together. They will expand & contract up to 2mm per cell (normal) during their cycles. You do not want them to Puff or Bloat. REFER TO MANUFACTURER SPEC SHEET ! Typical recommendation is 12psi @ 50% SOC
TIGHTENING TORQUES:
- 70 kgf.cm (5.0 lbf.ft)
- 35 kgf.cm (2.5 lbf.ft)
- 7 to 12 kgf.cm (0.5 to 0.9 lbf.ft)
LASTLY:
Ensure that Cell Contact surfaces are clean of greases, waxes & oils (there is often cutting oil from tapping cells and waxes to protect from corrosion.
Also, clean your BusBars regardless of type, again Oils & Waxes can cause issues with readings.
GUARANTEE that there are no Burrs, Ridges or Edges on the busbars. The stamped ones all have a slight ridge. Made ones always have burrs.
-- File them ridges down or chamfer the holes slightly which is better.
You can use a very small amount of NoAlox/OxGuard on the cell contact surface to reduce corrosion potential. DO NOT GET ON THREADS ! It is a grease and will seriously affect PSI readings when tightening bolts. Stripping the thread = BAD.
NOTE, the above oils, waxes, ridges can and do affect readings, and can cause IR issues where cells posts will heat up due to poor contact. They can also create other side effects which are not immediately observable.
Hope this helps, Good Luck.
Steve
That's an office / warehouse. I do not believe they have production facilities in North America.
Xuba is offered me CATL 300AH and gave me the same mandarin PDF someone else in this thread linked.
The QR code could tell you a lot, but in many cases its not east or not possible for the end user (or the reseller) interpret the QR code or serial number. Sometimes, the manufacturer gives guidance on how to read the serial number in the datasheet.
I ordered them, sales person said Grade A and capacity of 300 or more. PDF's call 1500 cycles and 0.5C discharge rate.
Person I am speaking to said the battery's are grade A too.
what happens return wise, if you receive the cells, measure them, and they are not grade and have only 280ah capacity instead of 300ah? do you eat the shipping cost or do they have to send out replacement battery with a shipping label? or do i call my visa?A reseller saying they are A grade is a sure guarantee that they either are A grade, were A grade, or are not and never were A grade
Xuba has a decent track record, not perfect, but decent. I imagine you will be happy with your purchase, many of the cells people bought from them don't test to 100% capacity but they tend to be within 95-100% with a few outliers (these are the EVE cells). So while they may not be grade A cells, they are still a very good deal.
As a general point, it is very rare for a reseller to admit that any cell is anything other than grade A or maybe A-. Don't read too much into what resellers say about (1) cell grade (2) matching. These are highly discounted cells (speaking generally, I don't know the price of these 300Ah CATL cells) being sold at a fraction of the price of what new A grade cells sell for. The likelihood of cells being non-A-grade is quite high. The sellers are middlemen, not specialists, some may be more knowledgeable than others, but most are generalists flipping discount cells, its not likely they are able to provide (or necessarily understand) actual matching, or even be able to provide cells from same date/batch. Its still worth asking about these things, but don't be surprised if they do not understand or can't do so, or make promises they cannot keep.
That's a bit of a grey area. And one reason why it makes sense to get things in writing and make sure you and the seller are on the same page about details. And also moderate your own expectations. This is why I probably sound like a broken record about cell grade sometimes. People have, and sellers promote, unrealistic expectations. Cells being sold through unofficial channels at B grade prices could be and sometimes are A grade, but the likelihood is that they are not.
, the vast majority of people are relatively happy with their purchases and pay a fraction of what it would cost to buy premade drop-in batteriesThe solution is to first parallel top balance them. Then put them in series and keep them between the knees. For example I have 280ah eve cells. My 8S pack tests at 272ah's. My usable capacity is 250ah's keeping the high and low between the knees. Still a great deal.
Sure, this might take 60 days, as I paid ocean freight only. I already have test equipment and I also paid for 1 cell to be tested and I added one extra cell for discard.
Yes, they are going to laser weld a threaded post to them.
Totally agree with you. I can't be paying half the price and expect double the capacity. There must be a catch like everything in life. In this case I'm expecting that the batteries will only handle 1500 cycles and not 3000/4000 cycles.
1 | What's the minimum capacity per cell ? Or is there any guaranteed capacity ? |
2 | What's the terminal type and bolt diameter/depth ? |
3 | How many cycles should we expect and what's the nominal charge current allowed ? |
4 | If batteries come damaged through shipping, would you supply a replacement for the damaged batteries ? Do batteries come well packed on wood crate or similar to avoid shipping issues ? |
5 | If we test capacity using official methods on acclimatized room and find a cell with lower capacity than advertised , is a replacement offered ? How long for such replacement ? |
6 | should we expect brand new cells with original manufacturer QR Codes or repacked batteries ? |
