What was your discharge cut off voltage ? 2,8V as shown in the Diagramms ?
Yes, I have not changed that.
Thanks for the review!
(I got lucky. I ordered some last night, prior to the review coming out.) 
Nice to see, thank you!
I find this to be one of the best performing cells out there, and the capacity is just a bonus! Always good to get confirmation HKJ style, great to see the charts and get a feel for just what it’s doing.
Awesome work, as always, and again, Thank You!
Excellent. Now you are just missing to compare it with Sony VTC5A.
And also LG MJ1 would be nice.
Excellent review HKJ.
Glad I have few of these before the restrictions on shipping of Li-Ion cells from China by some of the online retailers
i used 2 of these new and in series in my ec4s. to my surprise, my opus showed that they took a very different amount of charge to refill each one. i see that as very bad. what should i do ? try it again, try 2 more new batteries, or just chop them in half with an axe ?
Thank you for the review HKJ.
I hope my flat-tops finally are on their way to me (yes, I was NOT on the GB and received button-tops).
I find that the only cell that comes close to the 30Q is the Efest 35A or 3000mAh Dark Purple cell. Everything else falls short, including the Sony VTC5. I haven’t seen a VTC5A, so that one I don’t know about. The LG HE-2 falls short, as does the HE-4. What used to be the king of cells, the Samsung 20R, can’t touch it. (ok, well, the 20R does pretty high amperage but falls so fast due to it’s 2000mAh capacity)
That said, the light that I have that will draw the most current from a single cell prevails on the LG HE-2. 21.1A is the highest I’ve seen from a single cell in a flashlight, this is in a Titanium X6 Quad 219C. The 30Q and 35A are right up there, but not quite at that level. This is a rare case though, and in virtually every other light I’ve tried em in the 30Q is top dog.
If you’re looking at what the numbers are during charging then that’s very misleading. You have to do a discharge test in order to see what the capacities are. Even that is not extremely precise with low price chargers. My hobby charger seems to be 10% lower than my Opus, but which one is closer to being correct is impossible to say.
I think what @tarver asking is why his 2 batteries take on different amount of charge after being used in his EC4S.
Running a discharge test will shows the capacities of both his batteries, which is another issue whatsoever.
But if he has not done so, it is best for him to do it first so that he can concludes that both batteried that gone into his EC4S has roughly the same capacity.
To me, if @tarver try 2 more new batteries in his EC4S and still get different amount of charge to refill, it’s more likely due to his light.
Nice one HKJ. This cell is no joke!
Thanks, HKJ!
Thank you for your quick answer !
As I am always testing capacity of my rechargeable batteries, I was not really sure if my measurements were really accurate using my, in comparison to yours, budget equipment.
I have got 12pcs of 30Q and I am quite happy to see that my measurements pretty much match with yours (I´m just doing simple capacity testing up to 3A).
Hi, everybody!
I need a help about INR18650-30Q battery manifacturing date code.
For the other Samsung elements refers written below:
■ Cell package : The bare cell is packed by which packaging material, PET tube.
■ Model and tube marking : there are three lines on the cell tube as follows.
Line 1 : INR18650-25R —- cell model name
Line 2 : SAMSUNG SDI —- cell manufacturer
Line 3 : 2D51 —- date code (Capacity ; “2” is over 2.0Ah, Year, Month, Week)
But 18650-30Q element have different Line 3 code. Only three letters. The principle of the code is different. I don’t know whether the item is new or 1-2 years old.
Since the Samsung 30Q is a relatively new offering, it simply cannot be 2 years old.
(I do have an atrocious time line memory, so 2 years could be “new” to me, sorry if that is the case. Bottom line is, it really can’t be an old enough cell to really matter. Authenticity would be far more important and there are other identifiers for that.)
See the 1st line on the can under the wrapper, 3rd digit = year, 4th digit = month.
I found it here.
Thank’s tkd15 ! 
I understood. This is Lot marking.
■ Lot marking :
There are three lines on the cell metal can as follows.
Line 1 : J5D5 —-
1st digit: Line number ( “1” for cylindrical line No.1, “J” for cylindrical line No. 8)
2nd digit: Final number of Model Name (“5” is INR18650-25x)
3rd digit: Year ( “D” is 2013)
4th digit: Month ( “5” is May ; A is Oct., B is Nov., C is Dec)
Line 2 : 45221 —-
1st digit: Negative coater number ( “7” is No. 7 coater)
2nd ~ 4th digit: Batch number
5th digit: Serial No. of assembling
Line 3 : 62F1 —-
1st digit: Date (“6” is 6th day ; 10 is A, 11 is B…)
2nd digit: Serial No. of winding in a batch
3rd digit: Reel No ( “F” is F reel ; A is A reel, B is B reel, … F is F reel)
4th digit: Winding Machine No. ( “1” is No.1 winder)
Is the flattop 30Q a raised flattop that will work in series?
No, the top of the pos is actually lower than the plastic wrap and washer. My HG2 are actually higher than the plastic.