Dolidada cells with low capacity and an inaccurate Zanflare C4

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…

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.

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 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).

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.

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.

Agreed. Testing 30Q cells on my Lii-500 using 500mA discharge rate, I get about 2900 mAh.

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.

“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.”

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.

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

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.

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”.

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

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. ENDED - #22 by patmurris

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.

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 ^:)

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.

Guys…thanks a lot for your help! I’m afraid things are now even more complicated than originally expected…

Yesterday, I did an additional NOR test (C-D-C cycle) on three Samsung 35E and one Sony VTC5A…all of them are flat tops. The 35E has a nominal capacity of 3.500mAh, the VTC5A has 2.600mAh. Now, if you have a look onto the picture below it becomes clear that the Zanflare C4 is “a bit high” on all cells I have charged so far. The charger was in stage 3 of the C-D-C cycle when I took the picture revealing the capacities. iR readings were collected before.


That takes me to following conclusion:

  • My Zanflare C4 is absolutely inappropriate for measuring battery capacities, not only because it indicates too high values but also because slot #2 always indicates around 75-150mAh more than the other slots. It makes me wonder if it’s just counting wrong or if the device really “over-dis-charges” the cells. I doubt the latter case but how can I be sure? However, the device appears to stop discharging at 2.8V and charging at 4.20V as it is meant to be.
  • Most probably, my C4 is not a “faulty” one but more likely the product itself seems to have some kind of a design flaw when I compare my results with HKJ’s statement that measured capacities are “a bit on the high side”. I muss confess I was not aware of the right meaning when I read it first, so I still bought this device. However, iR readings seems to be fine as you can see on the secound picture.
  • Now, taking into consideration that all 18650 cells probably indicate too high values (up to 10% more on slot #2) it puts the Dolidada - the name reminds me in a fittingly way of dadaism by the way - into an even worse light. The actual capacity at 0.5A discharge current could be more around 4.700mAh instead of 5.000mAh - while the shrink label lets you think you bought a 5.500mAh cell. If you have received high dran KP cells with 5.800mAh under the same Dolidada brand in the past you’ll be even more surprised.

So, now I have mixed feelings about both the charger and the Dolidadas. There is no way to recalibrate the C4 to correct values, is there?

Danke Dir light-wolff! Those 30Qs were from NKON which is to my mind a trustworthy reseller from the Netherlands. So, as I stated above this post - the charger seem to be inaccurate.

Thank you, also for checking your 30Qs capacity for comparison. I will repeat the test with my MC3000 and report back.

Thanks Lightbringer! Your comment made me start to smile…“Didgeridoo”…haha. :smiley: Yeah, I’m gonna ask the seller about his opinion. I just need to eradicate all the other variables in the equation before (i.e. to assess the capacity in the MC3000 for comparison). According to the charger I’m not sure how to proceed. If I ask Gearbest they would - in the best case - probably just send me another inaccurate C4 charger.