These are my own observations of a few Sofirn batteries:
Sofirn "5500mAh" 26650:
- there are at least 2 types (bought them bundled with Sofirn flashlights, at different times).
- their wrapping are similar, but the top look slightly different (will upload pictures next time)
- I used SkyRC MC3000 to charge to 4.20v, then run a discharge at 1.0A discharge current, down to 2.50v cut-off voltage:
- 1) Sofirn 26650 with a somewhat "raised flat-top" has these result:
- around 50mOhms (MC3000 DC IR reading), and capacity test yields around 5300-5400mAh capacity (MC3000 1A discharge current from 4.20v to 2.50v)
- using the YR1030 battery resistance tester will give around 42mOhms AC IR
- testing on some high-drain flashlights and measuring the tailcap current, gives lower current than many of my various 26650 cells, indicating this is like a lower-drain battery
- 2) Sofirn 26650 with a more "flat" flat-top has these test result:
- around 30mOhms (MC3000 DC IR reading), and capacity test gets around 5000mAh capacity (MC3000 1A discharge current from 4.20v to 2.50v)
- using YR1030 battery resistance tester will give around 14mOhms AC IR (very good - better than many of my various 26650 cells, indicating this seems to be a high-drain cell, maybe not as high-drain as the Golisi or iJoy 26650, but quite good, possibily matching or better than the Lii-50A 26650)
- testing on some high-drain flashlights and measuring the tailcap current, gives higher or similar current reading compared to my other 26650 cells
- I failed to note which of the Sofirn "5500mAh" 26650 are from earlier batch or later batch, because I got them both fairly recently (like a few months ago, and I only did more in-depth comparison capacity test recently)
(the one I refer to as "raised flat-top" 26650 is the right-most 26650.
(the one I refer to as "flatter flat-top" 26650 is the second from the right 26650.
(the left-most 26650 is the so-called Sofirn HD 26650 -- I haven't done much testing on it yet)
(the second-from the left 26650 is another Sofirn 26650, also similar low IR as the "flatter flat-top" Sofirn 26650; I haven't finished testing it yet)
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Sofirn 3000mAh button-top 18650:
- again, there are at least 2 types of this 18650 (possibly more); again I can only purchase Sofirn batteries when bundled with Sofirn flashlights
- I think the earlier batch has the lower capacity test reading, while the later batch gives a higher capacity test reading.
- physically, the 2 types look the practically exactly the same, I only noted they had to be different due to the YR1030 AC IR reading being different -- the YR1030 battery resistance tester generally gives very consistent readings
(button-top have some contact resistance, and my MC3000 gives inconsistent reading, so I have to keep on reseating them a few times and get the lower relatively consistent IR reading for my "test")
1) "older" Sofirn button-top "3000mAh" 18650:
- YR1030 battery resistance tester gives AC IR reading of around 24mOhms AC IR
- MC3000 DC IR reading is around 50+ to 70+ mOhms (again button-top now has some "issues" with my MC3000 slider...)
- capacity test (0.50A discharge current from 4.20v to 2.50v), gets around 2700-2800mAh capacity reading
- I wonder what actual battery is used (maybe it's the "pink" battery mentioned elsewhere in this thread?)
2) "newer" Sofirn button-top "3000mAh" 18650:
- using YR1030 battery resistance test, the readings are around 31-32mOhms AC IR
- MC3000 DC IR reading is around 70-90mOhms DC IR (again, button-top batteries give somewhat erratic reading on my heavily used MC3000, since the slider spring on my MC3000 is quite loose now...)
- capacity test (using 0.50A discharge current, from 4.20v to 2.50v), I get capacity test reading of around 3000-3100mAh capacity.
- though I didn't try tearing off the wrapper yet, I believe this is quite similar to the white DLG(H) 3200mAh battery (I have gotten the flat-top white DLG(H) 3200mAh 18650 from a local source and these have very closely related AC IR reading and capacity test reading), as these also give similar capacity test reading