Dolidada cells with low capacity and an inaccurate Zanflare C4

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.

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. :open_mouth:

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)

this may help or probably not

+1 :+1: :beer: :partying_face:

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