on aliexpress i see sellers of these sells with tons of positive feedback but in the photos, i see various mOhm reading. 24-70mOhm 
@500-1000mA. not sure what to make of it. i need 5 cells in series. do i buy a set and hope for best of matching mOhm? or should i get something else?
Analyzing chargers do not measure the DC internal resistance of cells, they measure 1KHz AC internal resistance as far as I understand. Additionally, the problem is they measure “at the circuit board”, this means they are measuring battery plus contacts plus rail resistances. Bear in mind that rail and contact resistances are of similar order of magnitude to a cell's internal resistance, and wildly variable at the hands of uninformed, couldknowbetter or careless users.
Personally I’d get something else. Assuming you have access to other choices and don’t mind spending a bit more money.
Chargers measure DC resistance, it would require some extra circuit to measure AC resistance and you do not find that in a normal analyzing charger,
I will correct myself then: I think the Lii-500 does not measure DC internal resistance. I know this because of a self-made extended cell capacity test in which I ensured minimization of rail and contact resistances before each discharge cycle. Check my Lii-500's internal resistance values for that test here: KingWei 18350 1000mAh 900mAh test.
Why do I know the 51 - 69mΩ displayed values are spurious? Because I later measured each cell's DC internal resistance by injecting DC current into them with my precision power supply, recording corresponding changes in cell terminal voltage and using those figures to obtain true DC internal resistance. I obtained a consistent average of ≈110mΩ. Two cells scored a 104ish - 105ish mΩ minimum while another a 116ish - 117ish mΩ maximum; they came packed up in pairs with a plastic wrap.
Henrik I must say I do not see how chargers, as a whole, use direct current internal resistance measurement. I've seen a lot of figures from different chargers here and there and I do not feel like they are doing that.
[quote=Barkuti]
[quote=HKJ]
The Lii-500 like all other chargers uses DC measurements.
It is not a question about feeling, but about circuit. Doing a DC measurement is fairly easy for a analyzing charger, it just need to measure voltage, turn current on and measure voltage again, then do a bit of math. AC requires a lot of extra circuit.
The precision of chargers is usual not very good, due to contact resistance and cheap implementations.
Thanks for pinpointing correction Henrik. The reason I ended up believing “they must be using an AC method” was because of the large divergence between my proven good DC internal resistance measurement method and those provided by the charger even if rail burdened.
Conclusion: cheap chargers measure internal resistance very poorly.
There is also the detail that different measurement methods will give different result, maybe I need to do some more writing about resistance measurements.
This can also be seen in my reviews of them.
Can i ask where you guys are buying the Genuine Liitokala 26650 cells, the ones that don’t turn inside out when you charge them?
I thought the Liitokala direct store on aliexpress was the one but it seems there are a few others such as the flag ship Liitokala store etc
The ones that don't turn inside out when you charge them… Is this serious? I know I can turn inside out a t-shirt, for example, but what 26650 cells turn inside out when you charge them? 
The LiitoKala whatever store phenomena is a consequence of many sellers selling the same product they can buy somewhere. Theoretically the most official store is #217753 (the one you get when you click/tap the LiitoKala banner at the bottom of their site's front page). They're known to be somewhat rogue, they even used the photograph of a known famous actress in their shop while contending she was their CEO Ashley zhang… 
I'd buy the cells in LiitoKala Direct Store (#1823237) and be done with it.
Yes totally serious some of the substandard 18650 & 26650 cells can explode, they cant handle high C drain or fast charge because they have small Lipo poly cells inside full size cases.
Thanks for the links
There is probably no such thing as “the” Liitokala store as even the supposedly official store sells fake 18650’s. However, I purchased my Liitokala 26650 from HERE and posted an initial capacity test HERE. It’s obviously a real 26650 that doesn’t turn inside-out, but…
The cells people are receiving seem to consistently report more than 5400mAh, while HKJ’s tests of both cyan and black Liitokala 26650’s were around 5200mAh at the 500mA discharge rate that many chargers impose. It’s not at all clear if these are still the same cells tested by HKJ, but I’ve found that my cell performs fine in my Astrolux FT03 SST40, which I use every day.
However, my LK 26650 is not quite as bright on a lux meter as a high-drain 21700 in the aforementioned light, so I would want a better cell in an FT03 XHP50.2. The Shockli 5500mAh is pricey and rather difficult to obtain unless you buy a pair, but it’s certainly a better cell, especially at 10A and above.
For $4.21/ea. with free shipping (for me in the U.S., at least), the Liitokala is an unbeatable value. I use my FT03 for sustained periods and tend to appreciate the long runtime of the 26650 when compared with the short-lived, slight brightness increase of a high-drain 21700.
At that price and capacity (1610mAh/$ for 10 cells, shipped), this should be a good cell for use in a battery pack. The cell mass might lead to cooling issues in larger packs, but likely only with extreme currents.
You purchased from #217753, liitokala Official Store, literally. No big deal, of course, I could have done the same. These cells are easy to obtain for chinese lads and lasses, they're manufactured by Power Long Battery, likely the market leader in 26650 development and manufacturing by a long shot. Their latest developments look to be in LiFePO4 cells, with the highest power delivery/discharge rate 26650 (rewrapped by Vapcell, reviewed by HKJ) and a newer, 3800mAh LiFePO4 cell (more here). From a more western standpoint their cell product page is an incomprehensible mess. 
Thank you for the replies leftdisconnected & Barkuti this issue of fake batteries really is a PITA
In China they are not content to simply Knock off a product at reasonable quality, as soon as a Chinese product gets any reputation for being good it is immediately knocked off again by other Chinese competitors then eventually just out right Faked
Trying to find legit batteries is an ongoing issue , I usually stick with Panasonic NCR18650 , if i see 3400Mah i consider them genuine (perhaps this is a mistake) but capacity readings on my charger are really all i have to go on.
With these newer 26650 cells there are already stacks of fakes which don’t even get close to their claimed specification and in some cases are quite dangerous, 2 sets i’ve tested so far struggle to make even half their claimed capacity and i have no idea what their TRUE safe max C discharge rating is
I have just ordered a batch from #217753, liitokala Official Store that leftdisconnected & Barkuti posted, il update the thread when they arrive to confirm if they still measure up to previous samples
You left off the letter after NCR18650. With 3400 I’m guessing NCR18650B. This is a very old model, the GA is newer and better.
With 18650 it’s easy to find legit cells. Stick to the big Japanese company brands (LG, Panasonic/Sanyo, Sony, Samsung) and buy from trusted sources. Don’t buy from companies you have never heard of or have no reputation.
26650 is a different story. None of the big Japanese companies make this size. You can still buy from trusted sources, though. I know a lot of Europeans buy from https://eu.nkon.nl/
Yes NCR18650B they have served me very well for a number of years and come in button top (protected) so i trust them in my multi cell torches ive not bothered to try anything else i assume you’re referring to the Sanyo NCR18650GA do they also come in button top protected??
Nkon is by far the best source for batteries in Europe, low prices and you don’t have to worry about fakes.