Our NEW GO-TO LiFePO4 vendor...09.20.21

At this point it may be a bit redundant, but since I was only able to make this purchase because others shared their experiences, I thought I would add my purchase experience with Jenny at Docan to the thread.

I have purchased two batches of 36 EVE 304ah cells from Docan.

The first was ordered on November 18th and paid with Pay Pal. No payment issues. Jenny told me that these were not in stock in the U.S. and would have to be shipped from China, so I should expect to wait at least a couple months. I emailed on January 19th, and she responded that they were in route to the U.S. Another month had almost past, so I planned to email again on February 19th, however when I arrived home from work on February 17th, a bunch of boxes were in front of my garage door. Happy Day! I'm glad my UPS driver was conscientious enough to bring the boxes up right by the door in front of my pickup, because I had no idea they were coming and they could have been sitting there for a while. So lack of communication on the expected arrival date was the only hiccup in this transaction. No damage. Did the cursory voltage check and weighed each cell to compare with the specification, and everything looked good.

The second was ordered on April 4th. I tried to pay with Pay Pal again, but Alibaba would not let me pay the entire transaction with Pay Pal. I went through several days of song and dance with Alibaba, using different credit cards, calling the credit card customer service to see if they were blocking the transaction, sending photo I.D. to Alibaba, and making some smaller Alibaba purchases with the card I wanted to use. Finally, with no explanation, they accepted the card they had previously declined. This order also had to be shipped from China. This time Jenny had emailed me with the approximate delivery date of June 5th to 10th. They arrived on June 5th, and all was good once again.

Once I heard about the LiFePoQR app, I scanned the codes on all of the battery cells to get the manufacture dates.
The first batch, ordered on Nov 18, 2021, consisted mostly of cells manufactured during the last week of October 2021 or the first week of November 2021. There was an exception with two of the cells that were manufactured on June 27, 2021.
The second batch, ordered on April 4, 2022, consisted of cells manufactured in the first week of March 2022, with the exception of one cell which was manufactured on February 12, 2022.

All things considered, I am pleased with this purchase. No egregiously old cells and no obvious issues.

After they have sat in my basement for a few months, I have finally put together one 4S battery, which I plan to use it with an iCharger X8 to capacity test some of the other cells. I ran one cycle on the battery, and it appears to have capacity in excess of 304ah, but I have some uncertainty over the exact number, so I'll leave those questions for a different post.

hankcurt said:

All things considered, I am pleased with this purchase. No egregiously old cells and no obvious issues.

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Good to hear things went well with your two buys. Will be interesting to see how long my second buy takes to arrive from China. Hopefully covid becomes less an issue and things start moving faster. Yes, mine were just dropped off by UPS too, no signature required.

GRBreaks said:

Just John wrote: The "stages" theory of top balancing is just silly. Charge them up as quickly as possible. Best way to do this is to use a BMS and charge a pack until high voltage disconnect (you did test that works on your BMS first, right?). Then you can parallel and finish the top balance.

Browneye wrote: It can take a LONG time, so most will connect in series with the bms and charge them to 90-95%, then do the top balance. You'll probly still have to do some fine tuning.

To which I say: I wouldn't trust several thousand dollars worth of new cells to a new BMS. >snip

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You're supposed to monitor the process when you do this, not just leave it to its own, so you don't fry "thousands of dollars worth of new cells."

At the end you contradict yourself and recommend a series charge to get the ball rolling. Actually, the old guard recommend you charge to like 3.4 or 3.5 to near zero current, THEN wire parallel and finish the top balance to zero current at 3.65V.

My point was that 8 x 280A cells could take an interminable length of time to parallel top balance with five or ten amps. I had 4 x 230 and it took about four days with a 30V-10A bench supply. The first mistake I made was thinking it could be done in stair-step stages, something I saw recommended that made sense to me, and so you could monitor progress and not over-volt them. So I started at like 3.5V charging. But when the cells get close to full then current tapers way off, I was sitting at like a couple of amps, for hours - a day. So I restarted them at the full 3.65V and they charged all the way up to zero current. It took so long I thought something was wrong.

> At the end you contradict yourself

IF you know your equipment well, go ahead and try variations on the series charge
to do an initial top balance, I won't argue if that's what you want to do.
It can make sense if you have lots of cells and/or not much time.
Perhaps finish the cells off using that series connection with a 10A charge current
using a BMS capable of several Amps of active balance as I had suggested.
You only have to wire up the cells once. Seems ideal.

Do you know if there is a voltage spike when the BMS contactor cuts out due
to your 100A charger not reacting fast enough to reduce the current down to 0A?
Several instances of this blowing out chargers and/or inverters here on the forum.
I consider the BMS contactor to be a good fail safe to have, but not exactly a tool
to depend on.

Telling everybody with untried BMS devices they don't fully understand
to just go for it seems not quite so ideal.
Most of us punters are better off doing a parallel charge from the start.
A week spent charging them is not much of a burden if the cells take months to arrive.

You are right, a parallel charge at 3.4 volts tails off considerably once the cells reach 3.35 or so.
Most of this is due to the resistance in the wires, most of that in how you wire up the cells
(even if using 10awg wire), and some inside the power supply (after the point it senses the voltage).
A little bit would be due to internal resistance of the cells, but that should be a fraction of a mOhm.
Yes, I did cheat a bit on my recommendation, bumped the supply up to 3.5V after seeing it crawl
along toward 3.4V for a day or two. But once up at a solid 3.4V, it's just a few hours up to 3.5V
and then minutes to 3.6V, so monitor closely.

If you don't think the cells will get damaged if held at 3.65V for long periods, then just
set your supply to 3.65 and check it once every 12 hours during the parallel top balance.
If somewhat more cautious like me, don't do that.

(First post...)
I am pretty fully researched at this point and ready to start acquiring system components.
I see Docan and Jenny, I've seen the issues of cell grades and I'm down to just shopping price and a reliable transaction.
I came across Gobel and their $105 for the EVE 280ah K model shipped from China. What I found interesting is in the link to their site describing what I understand to be that ALL of the supplier cells are what are known as "B" grade and that the the true "perfect" cells are all absorbed directly through EVE's big business contracts. Note their last bold paragraph below, they describe the ratings as:

"Cell Grade:

In our system, Grade HSEV>LSEV>ESS.

Grade HSEV are the best quality cells, which are sold in EVE official shop. HSEV cells have strict matching standard, so price is pretty high.

EVE sell ESS cells to distributor such as Gobel Power. These cells are the second best quality cells you can get in the market.

Gobel Power do some tests and group better matching cells toghter, these are LSEV cells. LSEV cells have better matching standards than ESS cells.

If not all, 99% distributors have only ESS grade cells, no matter how they call these cells, Grade A+ or Grade A, they are ESS cells.

To discriminate HSEV cells from ESS cells, EVE starts to print B Mark on ESS cells, these cells are same as Intact QR cells, The only difference is QR.

Why EVE do it? In previous months, some distributors claim their cells are HSEV cells, but actually they are ESS cells. At that moment, Both HSEV and ESS cells have Intact QR, the only difference is HSEV cells have official testing report (Excel or Paper format), but testing report is easy to counterfeit, so EVE starts to print B Mark on all ESS cells."

If "ESS" or "B" cells are what we get from all of these distributors, so be it, I figure if they are undamaged, fresh and meet capacity and performance.
My questions come to this:
Anybody have transactions with Gobel?
Have "we" purchased a whole bunch of "ESS" cells represented as "A" cells?
At $105 + shipping, if these are indeed the same as the best of what "we" have been getting, it appears something just under $4000 for 32 of these all said and done. Am I seeing a best price story or a lesser quality story here?

I quoted what I thought mattered, but here's the link:

Jaxonwood said:

At $105 + shipping, if these are indeed the same as the best of what "we" have been getting, it appears something just under $4000 for 32 of these all said and done. Am I seeing a best price story or a lesser quality story here?

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I mean it's $5 cheaper than Docan who many people (incl. myself) have bought from and been happy with. Worth saving $5 a battery? Up to you man.

Rossman said:

I mean it's $5 cheaper than Docan who many people (incl. myself) have bought from and been happy with. Worth saving $5 a battery? Up to you man.

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I show $4768 delivered from Docan.
From Gobel, I'm doing some easy math of $3360 + a scientific wild ass guess of $550 in shipping = $3910
I haven't run it on the calculator but it looks more than $5 per cell , hence my inquiry.

Jaxonwood said:

I show $4768 delivered from Docan.
From Gobel, I'm doing some easy math of $3360 + a scientific wild ass guess of $550 in shipping = $3910
I haven't run it on the calculator but it looks more than $5 per cell , hence my inquiry.

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The price from Docan shipped from Houston for 32 LF32K cells is indeed $149*32 = $4768,
plus a 2.04% alibaba fee plus a 3% fee if you use a credit card. Plus sales tax if any.
The price from Docan shipped direct from China is $110*32+shipping+2.04%+3%.
See my post of July 21 for more details. I suspect that comes out quite close to Gobel's.

There is no legal definition of A+, A, or B, vendors are free to claim whatever they wish.
As you say it doesn't much matter, all I want is something that works for off-grid power.
Who I buy from comes down to vendor reputation. Some people thought they were getting
"A" cells from alibaba vendors and wound up with obviously used or damaged cells.

How things like air compressors and automotive jump starters get sold here in the US can be
a bit creative too, the specs many vendors claim violate the laws of physics.
There seems to be no legal consequence.

Yes, I can believe electric vehicle makers get to cherry pick the best cells when buying
several million. When only buying a dozen or two, we pay double that $110 price if
we want the same grade of cells since it's so much harder to deal with so many different
(and often bumbling) customers. What I got from Docan is new, unblemished, and works well.
But other vendors have figured out that they can sell used cells since it is so much hassle
to return defective product.

As an example of slightly mismatched cells, here's what I see with my 32 cell bank at 54 and 56 volts.
At 54v: 3.367 3.382 3.373 3.365 3.386 3.365 3.359 3.378 3.368 3.368 3.367 3.367 3.377 3.366 3.380 3.376
At 56v: 3.508 3.480 3.482 3.523 3.473 3.521 3.530 3.483 3.492 3.496 3.509 3.504 3.482 3.500 3.477 3.483
Note that at 54v, cell #5 is the highest of the bunch at 3.386v and cell #7 is lowest at 3.359v.
But at 56v, cell #5 is lowest at 3.473v and cell #7 is highest at 3.530v.
Currents were very low when these readings were taken, so not a matter of internal resistance.
I would guess this is due to slightly different chemistries of the cells, and this flipping around
will cause my passive BMS balancer to waste a few watt-hours. I'm ok with that, would much rather
have twice the cells for the same money than save a handful of watt hours. If you care, an active BMS
wouldn't waste much power at all, as it moves the power from one cell to another instead of burning it up
in a resistor.

Cells 5 and 6 were built on Dec 10 of 2021 and Jan 6 of 2022, respectively. From the QR codes:
manufacturers product_types cell_types model_codes capacity production_date production_city factory_product_line factory_task_order number_of_cell_produced_that_day original_qr_content
#5: EVE Power Cell LiFePO4 LF280K 280Ah 10/12/2021 Jingmen 84 66 6278 04QCB76846600JBCA0006278
#6: EVE Power Cell LiFePO4 LF280K 280Ah 6/1/2022 Jingmen 84 25 6896 04QCB76842500JC160006896

Jaxonwood said:

wild ass guess of $550 in shipping

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Exactly. A wild guess. Why not get an actual shipped quote from Gobel before you make your claims?

I mean it may be cheaper, I have no idea - but I'm confused how you would think think two suppliers from China will have wildly different shipping rates? They will both ship the same way.

Rossman said:

Exactly. A wild guess. Why not get an actual shipped quote from Gobel before you make your claims?

I mean it may be cheaper, I have no idea - but I'm confused how you would think think two suppliers from China will have wildly different shipping rates? They will both ship the same way.

Click to expand...

Given the $4768 price he quoted, I assume he is buying 32 cells.
My buy of 16 cells from Docan shipped from China was $110 each plus $276 for shipping,
so his figure of $550 is about right.

What he missed was that the Docan price of $149/cell is the price shipped from Houston,
arriving in a week. For $110/cell, Docan can ship to you from China, plus $276/16=$17.25
for shipping, so 127.25 per cell to make a fair comparison of the $149 price from Huston.
Of course, shipping from China will take 1 to 3 months.

Also missing in his calculations are the 2.04% alibaba fee and then the 3.00% fee for credit card use.
That's on top of the prices quoted by Docan, and likely Gobel as well, doesn't matter if it
is shipped from Houston or China. See my July 21 post here for more details.

A quick search of this forum for "Gobel" finds only a handful of references, mostly in regard
to their early QR decoder. They may be ok but I don't see anybody who has bought from them.

There have been vendors asking far less than $110.00 per cell.
When you see a price of $50/cell, best to assume it is used or damaged.

GRBreaks said:

Given the $4768 price he quoted, I assume he is buying 32 cells.
My buy of 16 cells from Docan shipped from China was $110 each plus $276 for shipping,
so his figure of $550 is about right.

What he missed was that the Docan price of $149/cell is the price shipped from Houston,
arriving in a week. For $110/cell, Docan can ship to you from China, plus $276/16=$17.25
for shipping, so 127.25 per cell to make a fair comparison of the $149 price from Huston.
Of course, shipping from China will take 1 to 3 months.

Also missing in his calculations are the 2.04% alibaba fee and then the 3.00% fee for credit card use.
That's on top of the prices quoted by Docan, and likely Gobel as well, doesn't matter if it
is shipped from Houston or China. See my July 21 post here for more details.

A quick search of this forum for "Gobel" finds only a handful of references, mostly in regard
to their early QR decoder. They may be ok but I don't see anybody who has bought from them.

There have been vendors asking far less than $110.00 per cell.
When you see a price of $50/cell, best to assume it is used or damaged.

Click to expand...

Ok, so if the big picture is coming in now, Docan has the big advantage, if true, of being able to return defective shipments to Houston and Gobel, it would seem, is a one way trip, take it or... haggle/beg for some adjustment. Also, all other things the same, it is a $5 difference.

On the Docan site I was not able to get or see the $110 price for shipped from China units, is that an email to Jenny Wu to get that $110?
Also, does anybody feel confident or know that bad cells can be returned to their USA warehouse?

This is the sixth 12 volt 280 ah battery I have done with cells from Docan, all of them balanced well. Here is a screenshot after a 72 hour top balance, 25 amp draw to inverter low voltage cut off at 11 volts and then full charge, I never saw any balancing during charging.

Jaxonwood said:

Ok, so if the big picture is coming in now, Docan has the big advantage, if true, of being able to return defective shipments to Houston and Gobel, it would seem, is a one way trip, take it or... haggle/beg for some adjustment. Also, all other things the same, it is a $5 difference.

On the Docan site I was not able to get or see the $110 price for shipped from China units, is that an email to Jenny Wu to get that $110?
Also, does anybody feel confident or know that bad cells can be returned to their USA warehouse?

Click to expand...

Whether you have them shipped from Houston or China, you can work with Jenny Wu: jennywu896@gmail.com
or Amy Zheng: amy@docanpower.com who I believe are both based in China and both employees of Docan.
Yes, you get the Docan price for shipping from China by sending email to your sales person.
The price for shipping from Houston is on their website at http://www.powerwholesale.net/
Jenny and Amy can help you start an order either from Houston or shipped from China.

The primary Docan advantage is that this thread has a fair number of people reporting success when buying from Docan. (Also one or two reports of trouble, but that seems rare and it isn't always be clear where the fault lies.) There have been vendors where some people got good product, and then they started shipping obviously used or damaged items. Or vendors that always ship banged up used cells after claiming they are shipping new A+ cells. Another Docan advantage is that they have the Houston warehouse, shipments within the continental US typically arrive at your door within a week of the order. Ordering from Docan and having them ship to you from China is cheaper, but it takes a couple months for the cells to arrive, this is comparable with most other alibaba vendors as very few have a warehouse in the US. (I vaguely recall seeing one other that is copying Docan's strategy).
Gobel may prove to be a perfectly fine vendor. At least the price is not suspiciously low. They did good work for the community by making the QR decoder available. But I don't see any reports in a quick search of the entire diysolarforum where somebody bought from them, perhaps I wasn't thorough enough. You could be our test case, and save $5/cell in the process.
It is my understanding that a faulty cell shipped from China by Docan can be shipped back to Houston instead of China if you wish, but you should ask your sales person for confirmation before assuming that is true. There may well be plenty of haggling involved to return cells to Docan. I made a video of my unpacking process so I would have some vague proof that they arrived damaged, but I have had no issues with any of my Docan cells.

Edit: Docan is especially interesting if you are within driving distance of Houston. You can inspect your cells when you pick them up. Or at least stand outside in the Texas heat and picket the warehouse if they do send bad cells.

You can also use this site: https://www.docanpower.com/
I use the site to see what they have then I contact Amy to get the details on complete pricing and shipping.

I did try to look a Docan's website before I purchased, but didn't really find very helpful. In the U.S., the expectation is that you should be able to go to a website, see a product description and a price, figure out your shipping cost and place an order without human interaction.

When dealing with Chinese companies, even on web based commerce sites like Alibaba, they use the website kind of like brick and mortar stores use a guy standing outside of the store spinning a sign. The websites main purpose is to get you to contact them. Their web store information tends to be riddled with errors and contradictions, and is often not up-to-date. The only way to complete a transaction is to text chat with a live person online.

Also, they are often using translation software, or have limited english language skills, so don't use complex sentences and avoid compound sentences. Each sentence should have one subject, one verb, and one meaning or one question. It makes communication go much more smoothly. Of course all slang and regional terms, similes and metaphors, and any English specific idioms should be avoided.

An example of something I thought would be clear, but wasn't, occurred when Jenny contacted me to say the battery cells were being shipped. I replied "Thanks for the update". The word update was confusing, and she had to ask what I was trying to tell her. (I think she might have separated the words 'up' and 'date' which causes it to make no sense. I replied using the word 'information' instead of 'update' and then she understood.

Here's another thread about buying from Docan:

TLDR:
Mostly good experiences with Docan, sets them apart from almost any other vendor folks in this forum have tried.
Buying spendy A+ cells directly from EVE can be problematic, they weren't packed as well as from Docan (one report).
Can wire money to a Chinese bank avoiding alibaba and credit card fees, but zero protection so must trust your vendor.
There are Docan sales people other than Jenny and Amy that get a good reviews.
Docan prices and fee structure have changed a bit over the life of that thread, one person reported
that buying from Houston cost the same as having cells shipped from China, definitely not true now.
I don't really know about buying other than through Jenny and paying the alibaba and credit card fees,
am curious if anyone has a better way than what I posted in this thread on July 21.

Summary: I'm happy with my buy.

hankcurt said:

The word update was confusing,

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My guess is that Jenny thought you might want something about the order updated.
So she followed through to see if further action was expected
English is tricky.

I learned enough Mandarin Chinese to be sort of conversational some 30 years ago, it's now long gone.
Fully sympathize with with anyone doing high dollar business transactions in other than their mother tongue,
dealing with all kinds of people with all sorts of expectations. For example, assuring them they will get
their cells when the ship has been sitting off the port of LA for a month due to the epidemic.

18650batterystore
Same or better price
Us stock
Eve welded dual helicoiled terminals
Shipped in crates if you buy enough.
My experience was free shipping plus 5% off the web price for 48pcs.
No I haven't yet tested them, inverters not up and running.

This is the first page I come up with for Prismatic cells from18650batterystore. Sad Besides the limited variety they are all sold out.

Web reviews are admittedly not reliable, but a google for "review of 18650batterystore.com" doesn't look promising. Here is one of the more alarming hits: https://www.facebook.com/18650BatteryStore/reviews Note that most of the good reviews on that webpage are suspiciously short and generic. On the other hand, this 2 year old reddit page suggests they are legit with some happy customers of vaping batteries (also mentions some other US based battery vendors) As littleharbor2 has stated, they currently have zero stock of their two kinds of prisimatic lifepo4 cells. Current prices are higher than Docan shipping from Houston. On the plus side, sounds like Maitake received his 48 cells at a good price, and they look new.