New Docan 230Ah EVE Cells

[Brett V]

I have received 32 EVE 230 Ah cells from Docan's Houston TX stock and 31 look pristine. They all measure 3.293 volts out of the box.
Number 32 is only reading 3.286 volts and also appears to have a defective weld on one side of the negative terminal. The square tab with the stud has a stepped down lip that gets welded, and it looks like this one was misaligned in the jig so the weld landed on the lip instead of the joint between the lip and top of the cell. I have emailed Docan and will be posting about the response.

I have mixed feelings about this new stud welding method. The surface area for the bus bar is large and flat. The square tab is only welded on 2 sides and if you hold it up to the light and squint just right, you can see the slimmest of a gap. I think this will be fine for most solar storage applications that typically have a lower C rate, and is probably more robust than I'm giving it credit for.

The cells themselves are mostly flat with a slight concave depression between the electrodes. It's only noticeable using a straightedge and will probably fill out with a full charge.

It's nice to see they are simply attaching a Docan label instead of the fake IR test sticker they used to apply. This seems more honest to me. The supplied bus bars are the thin layered ones and I actually prefer these to the thick stock.

I don't have the equipment to do a proper capacity test and for me, it really doesn't matter. I already have 2 batteries made from these cells and expect this batch to be the same. With a combined capacity of 230ah x 4, a few amp hours one way or the other isn't going to be much of a percentage of the total system capacity.

I would be 100% happy with this purchase if it weren't for the one defective weld, and how Docan deals with that will be a critical to my recommending these cells and Docan.

Stay tuned....

 

[740GLE]

As an owner of late 2021 style 230ah posts, I’d love to see how these 230ah compare to 18650 Eve 230ah cells, in terms of that stud welding/connection points. These Docan pictures look more like cold brazing joints than laser welding older threaded posts of years before. The bigger the glob the better the job?

Let us know how Docan responds.

What’s your rough max C you will use these cells for? .2C?

Anyone wager Docan is re-lasering these 230ah QR codes as well?

 

[Brett V]

As an owner of late 2021 style 230ah posts, I’d love to see how these 230ah compare to 18650 Eve 230ah cells, in terms of that stud welding/connection points. These Docan pictures look more like cold brazing joints than laser welding older threaded posts of years before. The bigger the glob the better the job?

Let us know how Docan responds.

What’s your rough max C you will use these cells for? .2C?

Anyone wager Docan is re-lasering these 230ah QR codes as well?

I have two batteries made from these cells, each with their own BMS, connected to a Growatt SPF 6k. When thes are done, I'll be replacing that with a 12k Growatt. Loads are light here, it's rare to exceed 50 or 60 amps for any length of time. Divide that by four batteries and the C is pretty low.

Not sure why they would re-laser the codes, these 230Ah cells are physically much smaller than the 280's and larger than the 160's so it wouldn't make sense to fake them.

 

[740GLE]

My only guess is the Grade B marking that Eve has been issuing to commodity cells.

 

[Brett V]

For what it's worth...

 

[Horsefly]

I'm thinking of buying some more Eve 230Ah cells myself. I like the look of the 18650store terminals, but the price difference for 8 cells makes it hard. Docan sells them for $111/cell, and the shipping is free. For 18650store, the cells are $120, and shipping for 8 of them to Colorado is $300. That works out to be $157.50 per cell. Makes it tough to NOT go with Docan.

I mentioned earlier that I bought Eve 160Ah cells and looked perfect and have performed well. I think @Brett V mentioned that perhaps the risk is lower on these 230Ah and 160Ah cells from Docan as they are not as popular, and maybe Docan isn't pressing through whatever they can get.

By the way: The Eve 160's are exactly the same width and thickness as the 230's, but a bit shorter. That means that the same bus bars fit both.

 

[740GLE]

I'm thinking of buying some more Eve 230Ah cells myself. I like the look of the 18650store terminals, but the price difference for 8 cells makes it hard. Docan sells them for $111/cell, and the shipping is free. For 18650store, the cells are $120, and shipping for 8 of them to Colorado is $300. That works out to be $157.50 per cell. Makes it tough to NOT go with Docan.

I mentioned earlier that I bought Eve 160Ah cells and looked perfect and have performed well. I think @Brett V mentioned that perhaps the risk is lower on these 230Ah and 160Ah cells from Docan as they are not as popular, and maybe Docan isn't pressing through whatever they can get.

By the way: The Eve 160's are exactly the same width and thickness as the 230's, but a bit shorter. That means that the same bus bars fit both.

Free shipping is huge!! In costs, that just kind of makes you wonder how cheap Docan can get these cells to offer free shipping, no such thing a free lunches.

That’s why I’d love to see close up on the 18650 230 terminals to compare.

 

[740GLE]

For what it's worth...

If they have the abilty to reprint QR codes for 280k cells they can print anything they want. A 2020 cell now becomes a 2022 cell in a blink of an eye. Just playing devils advocate.

It’s not like the QR code is some super secret sauce that can’t be faked.

 

[42OhmsPA]

For anyone on the fence about ordering from Docan or 18650, I'd recommend you contact Amy with Shenzen Luyuan.
She was quick to reply and provide a quote and is offering the new 2 bolt terminal (like 18650) or the older stud.
That reminds me I need to reply back to her.
I'm currently running 32 Docan 230s with the female threaded stud with no issues but I'm torn who to order from next.

 

[Horsefly]

For anyone on the fence about ordering from Docan or 18650, I'd recommend you contact Amy with Shenzen Luyuan.
She was quick to reply and provide a quote and is offering the new 2 bolt terminal (like 18650) or the older stud.
That reminds me I need to reply back to her.
I'm currently running 32 Docan 230s with the female threaded stud with no issues but I'm torn who to order from next.

I really do think highly of Amy Wan of Shenzhen Luyuan. I bought a batch of 280Ah Eves in 2021, and they were great. The only problem was shipping from China. The shipment was delayed quite a bit from what she had estimated, and at one point it seemed the logistics company just quit giving her the time of day. She was expressing extreme frustration with them, and the guy I was building a system for got so frustrated he told me to go ahead and order from someone with USA stock. He was willing to eat the lost cost of the cells from Amy, but I was clearly going to lose some credibility. Luckily things broke loose just before I placed an order with Docan and the cells arrived.

The logistics company - coordinating the shipment from China to a port in the US and then reshipping via UPS or FedEx - has no skin in the game. They know that both Amy and I can complain about how long it takes or how beaten up the packages are, and they will deflect and leave us to blame each other. Granted this was when the entire shipping "machine" was completely broken.

So while I highly recommend Amy, I don't think I'll ever buy from Chinese stock again, just because of the jokers between them and me. If a company has a US warehouse or it is a US company who buys from China, the great unknown of the logistics between China and the US is bore by someone else, not me.

 

[Brett V]

If they have the abilty to reprint QR codes for 280k cells they can print anything they want. A 2020 cell now becomes a 2022 cell in a blink of an eye. Just playing devils advocate.

It’s not like the QR code is some super secret sauce that can’t be faked.

I hear ya. I'd have a much higher level of confidence if the QR opened a web page hosted by EVE instead of Docan. All I have to go on is they do look pretty. The last two sets of cells I bought had one or two with minor dents and spots where a piece of the blue tape was applied to patch a nick in the covering. These are all spotless and consistent. It's always a crapshoot.

 

[740GLE]

For anyone on the fence about ordering from Docan or 18650, I'd recommend you contact Amy with Shenzen Luyuan.
She was quick to reply and provide a quote and is offering the new 2 bolt terminal (like 18650) or the older stud.
That reminds me I need to reply back to her.
I'm currently running 32 Docan 230s with the female threaded stud with no issues but I'm torn who to order from next.

230ah cells with two threaded posts, like the 280k cells?

Never seen those offered on 230ah cells.

 

[42OhmsPA]

230ah cells with two threaded posts, like the 280k cells?

Never seen those offered on 230ah cells.

Yup, just like the terminals 18650 offers on the 230s they sell.

 

[740GLE]

Wow last time I looked they had the welded threaded post similar to Docan.

Now we need someone to buy one of each and do a load test to compare.

 

[42OhmsPA]

If it weren't for 18650s shipping charges to PA I would have already ordered 16 of them...

 

[Alkaline]

Hey Brett, you know the drill peel off that black label and see if it has been sanding/re-lasered. It could be Docan is starting to carry real grade A for the 230? But only 1 way to be sure.

Also I would not worry about the welds you are fine.

 

[Alkaline]

That works out to be $157.50 per cell. Makes it tough to NOT go with Docan.

Completely ignoring the fact that you are comparing Real Grade A from 18650 vs Re-lasered grade B from Docan? Apples to Apples comparison, if Docan ever sold legit cells they would be at the same price or even higher than 18650.

 

[42OhmsPA]

peel off that black label and see if it has been sanding/re-lasered. It could be Docan is starting to carry real grade A for the 230? But only 1 way to be sure.

Also I would not worry about the welds you are fine.

I'll have to do this with my Docan I bought last year (I have an extra cell sitting in the box). Mental not made.
Could be an interesting comparison to current stock.

 

[Horsefly]

Completely ignoring the fact that you are comparing Real Grade A from 18650 vs Re-lasered grade B from Docan? Apples to Apples comparison, if Docan ever sold legit cells they would be at the same price or even higher than 18650.

I've said this to you before, and I feel pretty certain of this: There is no "Real Grade A" or "Grade B". The manufacturers don't use that term, and neither do their "real" customers. ALL the cells we have available to us are those that the EV/Automotive customers (that probably buy 98% of the cells) have not bought. So for one reason or another, we get cells that they don't want. There is no distinct gradation between some really good reject cells, and some really bad reject cells. They are all reject cells. You may be able to say that "18650store has access to better reject cells than store XYZ". I don't really know how you would know, but I guess you could say that.

I agree that Docan re-lasering cells is a bad look. I also think that they may sell cells of other sizes that are not re-lasered. I dunno.

Fact is, I don't know - and you don't know - the real pedigree of whatever 18650store, sun fun kits, or Docan are selling. Fact is, I'd be willing to bet they all get a mix of pedigree. I think it is highly disingenuous and with absolutely no factual backup that we assign "Genuine A grade" to any of them. Period.

And finally, I think the bottom line is this: Short of the cells being dented, shorted, leaking, or terminals falling off, I think almost all of them would do perfectly fine in the application most of us are aiming for: Relatively low C rate solar power storage. This seems to be a game we like to play. We strive for that last 2% of capacity that the cells were rated, but in fact... It really is 2%.

 

[Alkaline]

Sorry you feel this way, but I suspect many others feel the same, I'm just disappointed at how effectively the Chinese sellers have spread misinformation to the point the average joe has no idea what is what. ?