Dolidada cells with low capacity and an inaccurate Zanflare C4

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Lux-Perpetua
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Dolidada cells with low capacity and an inaccurate Zanflare C4

Dear all,

I recently bought a couple of 26650 cells branded with “Dolidada” at this store on Aliexpress. According to the specs on the seller’s webpage this cell should have a capacity of at least 5.500mAh with a discharge current of 20A. Usually, these cells were rewrapped high current Keeppower cells with up to 6.000mAh. Apparently, I was unlucky to get cells from another batch with different specs underneath the shrink.

I ran a C-D-C test with 0,5A of discharge current. The picture indicates the third stage of the cycle, i.e. cells are being recharged again. The test revealed that these cells only have little more than 5.000 mAh at low discharge currents. So, using these cells in a typical flashlight scenario with 7-9 amps would mean to have far less capacities than 5.144 mAh.

Is there any rule of thumb I can use for orientation when it is justified to raise a complaint against the seller for delivering poor quality cells? What are your experiences? I am totally clear about the fact that there is always some kind of variation in terms of capacity but these cells actually seem to be different from what they are supposed to be. I doubt they can even sustain a discharge current of 20 amps.

Edited by: Lux-Perpetua on 05/31/2018 - 03:52
raccoon city
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According to Lightbringer, you can't have enough lemons!

(Of course, he was referring to lumens.)  :FACEPALM:

tatasal
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Aliexpress has buyer protection on ‘items not as described’, in this case, you should show convincing proof that the cells are way below their claimed 5,500mAh capacity.

Lux-Perpetua
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tatasal wrote:
Aliexpress has buyer protection on ‘items not as described’, in this case, you should show convincing proof that the cells are way below their claimed 5,500mAh capacity.

How would that proof have to look like? Is a picture or a youtube video showing the measured capacity sufficient? It will be hard to proof anything above 2A discharge current for I do not have the right equipment to show the effects of high discharge currents (e.g. voltage drop).
ifratos
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Your Lii-500 picture can be a proof if show less than 5000 mAH ,not 5144mAH .
With 5144 mAH /first test its a good battery.

And God said, Let there be light: and there was light.( Gen.1:3)

tatasal
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FlashTom wrote:
tatasal wrote:
Aliexpress has buyer protection on ‘items not as described’, in this case, you should show convincing proof that the cells are way below their claimed 5,500mAh capacity.
How would that proof have to look like? Is a picture or a youtube video showing the measured capacity sufficient? It will be hard to proof anything above 2A discharge current for I do not have the right equipment to show the effects of high discharge currents (e.g. voltage drop).

Without special equipment, it will be very difficult to prove 20A current discharge inability.

On the other hand, let’s take as example the Sanyo NCR18650GA 3,500mah. IIRC it’s rated at a minimum of 3,350mah or .04% below rated capacity.

In this cell of yours, 5,500 x .04 = 5,280mah….which in my opinion is not actually far from the rated capacity.

It’s your call if you are going to the ‘buyer protection’ route for such a small capacity difference.

However, I am surprised by this development as I am used to several Chinese 26650 cells normally exceeding their Rated label capacity.

Lux-Perpetua
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ifratos wrote:
Your Lii-500 picture can be a proof if show less than 5000 mAH ,not 5144mAH . With 5144 mAH /first test its a good battery.

It’s a Zanflare C4, actually. Wink However, I personally disagree to accept nearly 500mAh of capacity missing, especially at such low currents. But that was actually part of my question. Is there a normal percentage of variation for battery capacities? All my 18650 cells have significantly more capacity than stated, e.g. Samsung 30Q with 3.200-3.300mAh instead of 3.000mAh.

It seems I drew a blank in the Chinese battery lottery which brings us to the wise saying “You get what you pay for”. Facepalm

tatasal
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FlashTom wrote:
ifratos wrote:
Your Lii-500 picture can be a proof if show less than 5000 mAH ,not 5144mAH . With 5144 mAH /first test its a good battery.

It’s a Zanflare C4, actually. Wink Samsung 30Q with 3.200-3.300mAh instead of 3.000mAh.

This is a surprisingly high capacity….I will test my iCharger hobby charger my brand-new 30Q just for this, and report the result.

Even my Opus, which normally goes a little over the capacity, never reported up to 10% over the rated capacity.

Lux-Perpetua
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tatasal wrote:
FlashTom wrote:
tatasal wrote:
Aliexpress has buyer protection on ‘items not as described’, in this case, you should show convincing proof that the cells are way below their claimed 5,500mAh capacity.
How would that proof have to look like? Is a picture or a youtube video showing the measured capacity sufficient? It will be hard to proof anything above 2A discharge current for I do not have the right equipment to show the effects of high discharge currents (e.g. voltage drop).

Without special equipment, it will be very difficult to prove 20A current discharge inability.

On the other hand, let’s take as example the Sanyo NCR18650GA 3,500mah. IIRC it’s rated at a minimum of 3,350mah or .04% below rated capacity.

In this cell of yours, 5,500 x .04 = 5,280mah….which in my opinion is not actually far from the rated capacity.

It’s your call if you are going to the ‘buyer protection’ route for such a small capacity difference.

However, I am surprised by this development as I am used to several Chinese 26650 cells normally exceeding their Rated label capacity.

Okay, this kind of calculation helps me to think about my options. For sure, these cells can still be used and they might work fine in low current scenarios but I don’t think they will be as good as those “Keeppowers-In-Disguise” cells former buyers have found in the past.

Lux-Perpetua
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tatasal wrote:
FlashTom wrote:
ifratos wrote:
Your Lii-500 picture can be a proof if show less than 5000 mAH ,not 5144mAH . With 5144 mAH /first test its a good battery.

It’s a Zanflare C4, actually. Wink Samsung 30Q with 3.200-3.300mAh instead of 3.000mAh.

This is a surprisingly high capacity….I will test my iCharger hobby charger my brand-new 30Q just for this, and report the result.

Even my Opus, which normally goes a little over the capacity, never reported up to 10% over the rated capacity.

I can also doublecheck these values with my MC3000, just to be sure. I know that slot #2 always indicates a bit more capacity than the other ones but here I have only used slot #1 and #4. If my C4 indicated too high values with 30Qs it would mean that the actual capacity of the Dolidada cell is even lower. Shocked

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Just to try and find out the capacity discrepancies, I am throwing into the fray this equipment

I am now charging my 30q, using my MiBoxer C4-12, manually set to 1A.

My iCharger already set to .20a discharge rate, terminal voltage cut-off at 2.80v, waiting for the 30q to be discharge tested after fully charged (photo above), to mimic the settings of Flash Tom’s Zanflare C4 and find the result differences that might lead to a comparative conclusion about the results of his tests of this Dolidada cell.

Discharging has started: .20a rate, 2.80v terminal voltage cut-off (hoping no power failure tonight for such a long session) Resting, sharting voltage after a short rest: 4.14v

Discharge capacity after 10 hours, 4 min. is 2,041mah, @ .20a rate, 3.49v remaining at this juncture:
Edit: This photo is no longer useful as there was a short power failure probably in the thirteenth hour, so the whole process of charging, etc. will be repeated. Ouch!

New session after aborted test due to power failure:
At this juncture, it’s 2824mAh, 2.84v (cut-off at 2.80v), elapsed time: 13h, 55min.

Discharging “DONE” after 14h 07min: capacity: 2860mAh. Discharge rate: .20A
Note: While the charging exactly ended at 2.80v, when I took the photo, the cell was already recovering (at 2.82v) and rapidly going up to it’s nominal, resting voltage (around 3.5 to 3.7v on healthy cells IIRC)

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https://www.youtube.com/watch?v=GhbuhT1GDpI

this may help or probably not

sorry all images down
thanks photobucket

Lux-Perpetua
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lostheplot wrote:
https://www.youtube.com/watch?v=GhbuhT1GDpI

this may help or probably not

+1 Thumbs UpBeerParty

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Frankly i think you are lucky to hit 5000mAh with these Dolidada cells!
From what i can tell from the vendor’s page, they look like those Liitokala 50A cells which are not bad – certainly not “lemon” cells.

The last 26650 cells i bought where high drain KP 6000mAh which tested around 5500mAh 5700mAh. No big deal to me.

It’s up to you to start a dispute… but when you buy funny name cells from china for less then $10 a pair, you should be prepared to be disappointed. But in this case the cells look very decent for the price. If you look around you’ll find reports of sand filled 18650 cells that tested at less then 1000mAh…

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I think using buyer protection on such a small discrepancy in capacity is inappropriate. You weren’t buying a name-brand cell, so you can’t call this a “fake” cell. Perhaps they did change suppliers, but that’s the risk you take if you don’t buy a name-brand. You might have a point if the cell is nowhere close to a 20A cell, but you’d have to do proper load testing for that. And any cell will not deliver its rated capacity at high load.

Try the cell in the light you were planning to use it in. See if the battery gets abnormally hot. If not, then you can probably use it.

Lux-Perpetua
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patmurris wrote:
Frankly i think you are lucky to hit 5000mAh with these Dolidada cells!
From what i can tell from the vendor’s page, they look like those Liitokala 50A cells which are not bad – certainly not “lemon” cells.

The last 26650 cells i bought where high drain KP 6000mAh which tested around 5500mAh. No big deal to me.

It’s up to you to start a dispute… but when you buy funny name cells from china for less then $10 a pair, you should be prepared to be disappointed. But in this case the cells look very decent for the price. If you look around you’ll find reports of sand filled 18650 cells that tested at less then 1000mAh…

At what discharge current did you test your KP 6000 cells? I’m a bit surprised for KP cells are known to exceed their nominal capacity printed on the shrink. However, thanks for sharing your point of view.

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WalkIntoTheLight wrote:
I think using buyer protection on such a small discrepancy in capacity is inappropriate. You weren’t buying a name-brand cell, so you can’t call this a “fake” cell. Perhaps they did change suppliers, but that’s the risk you take if you don’t buy a name-brand. You might have a point if the cell is nowhere close to a 20A cell, but you’d have to do proper load testing for that. And any cell will not deliver its rated capacity at high load.

Try the cell in the light you were planning to use it in. See if the battery gets abnormally hot. If not, then you can probably use it.

I agree with you. I’ll see if I can test it in of my high drain lights (Rofis MR70, ThruNite TC20) for any suspicious behaviour. My intention was to get cells with the same capacity and same iR to work in serial mode (e.g. 2s configuration).

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FlashTom wrote:
My intention was to get cells with the same capacity and same iR to work in serial mode (e.g. 2s configuration).

For cells to be used in series, always order them at the same time from the same place. That way, if you get under-performing cells, they’ll at least be matched. Better two underperformers, than one good cell and one underperforming cell.

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FlashTom wrote:
Is there any rule of thumb I can use for orientation when it is justified to raise a complaint against the seller for delivering poor quality cells? What are your experiences?
Personally, it would not be worth my time and aggravation to try to raise and manage a complaint over a couple of cells that fall a little short of the advertised specs. Move on and buy name brand cells next time.
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tatasal wrote:
FlashTom wrote:
ifratos wrote:
Your Lii-500 picture can be a proof if show less than 5000 mAH ,not 5144mAH . With 5144 mAH /first test its a good battery.

It’s a Zanflare C4, actually. Wink Samsung 30Q with 3.200-3.300mAh instead of 3.000mAh.

This is a surprisingly high capacity….


Agreed. Testing 30Q cells on my Lii-500 using 500mA discharge rate, I get about 2900 mAh.
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At what voltage do these cells discharge at in the Li-500?

If 2.8V, it may be possible to get a bit more capacity down to 2.5V.

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BlueSwordM wrote:
At what voltage do these cells discharge at in the Li-500?
“The charger discharges the cell to a bit below 2.9 volt” according to HKJ’s review.

Zanflare C4 discharges to 2.8V, according to HKJ. His review mentions: “The mAh display is a bit on the high side.”

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Those aren’t “lemons”. Lemons would be way lower capacity. They are somewhat disappointing, but you seem to have extremely high expectations and are a bit OCD about this stuff (based on your thread about the C4). It ain’t worth the effort to deal with it. If you want TOP END stuff and are going to apply that kind of rigorous expectations on outcome > buy it. Don’t go for deals.

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FlashTom wrote:
patmurris wrote:
Frankly i think you are lucky to hit 5000mAh with these Dolidada cells! From what i can tell from the vendor's page, they look like those Liitokala 50A cells which are not bad - certainly not "lemon" cells. The last 26650 cells i bought where high drain KP 6000mAh which tested around 5500mAh. No big deal to me. It's up to you to start a dispute... but when you buy funny name cells from china for less then $10 a pair, you should be prepared to be disappointed. But in this case the cells look very decent for the price. If you look around you'll find reports of sand filled 18650 cells that tested at less then 1000mAh...
At what discharge current did you test your KP 6000 cells? I'm a bit surprised for KP cells are known to exceed their nominal capacity printed on the shrink. However, thanks for sharing your point of view.

 

I have a lot of KP 18650 and 26650 cells and they all test over their rated capacity.  

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Okay…this is how the C4 finished with 4 Samsung 30Q with joint-welded button tops..

Thank you guys for your input and opinion about it! Beer
I will test these cells again in the MC3000 and discharge them down to 2.5V. Maybe there‘s some more capacity to be revealed and my assumptions and expectations were wrong in the first place.

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Your C4 results clearly show that either the charger delivers more or less random results or the cell are not genuine 30Q. The values are too high, and the variation between cells is also too high.
I would not trust these “measurements”.

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FlashTom wrote:
I will test these cells again in the MC3000 and discharge them down to 2.5V.

For a fair comparison, I suggest to set it at 2.80v, same as the C4’s terminal voltage cut-off.

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klrman wrote:

FlashTom wrote:
patmurris wrote:
Frankly i think you are lucky to hit 5000mAh with these Dolidada cells! From what i can tell from the vendor’s page, they look like those Liitokala 50A cells which are not bad – certainly not “lemon” cells. The last 26650 cells i bought where high drain KP 6000mAh which tested around 5500mAh. No big deal to me. It’s up to you to start a dispute… but when you buy funny name cells from china for less then $10 a pair, you should be prepared to be disappointed. But in this case the cells look very decent for the price. If you look around you’ll find reports of sand filled 18650 cells that tested at less then 1000mAh…
At what discharge current did you test your KP 6000 cells? I’m a bit surprised for KP cells are known to exceed their nominal capacity printed on the shrink. However, thanks for sharing your point of view.

 


I have a lot of KP 18650 and 26650 cells and they all test over their rated capacity.  

So i’ve heard, but i don’t have enough KP cells to tell myself.

The discrepancy i mention is about two “new” 6000mAh cells they came up with a few month ago. Tested on an Opus BT-C3100 with the default settings they actually came out around 5900mAh. Then the Opus has been reported to be on the high side for capacity tests… I thought the discrepancy was bigger, but still below specs at low current. Not sure which charger can really be trusted on that point and how accurate or inaccurate is mine either. http://budgetlightforum.com/comment/1277194#comment-1277194

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First thing above all, run the test several times to measure consistency.

Then, if consistently low, I’d try contacting Duodenum directly, asking about it, nicely, and see what they say. They might offer to throw some bux your way, offer replacements and you keep the originals, etc., just to try to placate you. Offer proof, as pix above.

Whatever they offer, it’s likely to be a good deal for the price spent.

If they insist they’re not at fault, that you’re the one with the problem, then yeah, make it “official” and take it up with AX. Again, offer proof, cite your earlier interaction with Dobelina.

Then sit back and enjoy the ride.

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Lightbringer wrote:

If they insist they're not at fault, that you're the one with the problem, then yeah, make it "official" and take it up with AX. Again, offer proof, cite your earlier interaction with Dobelina.

Then sit back and enjoy the ride.

Always funny to read your comments, Lightbringer.

Fellows, there are sellers from the Far East out there who may think they're going to sell more and better if they exaggerate the ratings of their products. I could even put blame on the big manufacturers as some of their stuff does not meet their wrap specifications, at least the way I see it. This is a deceptive business model which I do not like, and if we aim to change this (as with any other thing worth to be fixed) we are to set aside with our communication fears and tell 'em where they are doing wrong, in a rage-free and respectful way, and see how can we contribute to fix this. 

 

Cheers Party

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Exactly, which is why he should just contact Didgeridoo directly and ask them nicely what’s going on, then hear what they have to say, and hopefully offer. A few bux back makes them cheaper. Extra/Replacement cells means getting more cells. Either way it’s a win/win, just for asking. And it kinda puts them on notice that people can ask for what they paid for, even if “discounted” in price (ie, “getting a deal”) or exaggerated claims.

If they get bit a few times, it’d pay for them to list them more honestly at 5000 and have people be happy they got better-performing cells, instead of 5500 and feeling cheated.

And if not, p&m to AX and let them whap them into line.

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