I recently ordered some additional Nitecore 16340 (and some 14500) cells after having good results using them heavily over the past couple of years, and I wanted some 'fresh' ones on hand and figured this was a perfect time to pick those up;-). Since I was already doing an order (famous last words), I decided to add a couple of their 18650 cells to see how they would look, and since I had no real low-mileage 18650s on hand and wanted a couple. These are protected cells in the nominal '4000 mAh' category, and are rated for '5A Continuous Discharge Current'. Note: There is also a version rated for 10A, which has an 'HP' suffix.
Open circuit voltage (OCV) out of the pkg was:
#1 - 3.53V
#2 - 3.53V
Although it's neither good practice nor my usual to measure DCIR at other than full state-of-charge (SOC), I measured these purely for relative comparison of the 2 cells at delivery. DCIR at transport charge was:
#1 - 49 mΩ
#2 - 48 mΩ
I charged them @1A to 4.20V, then let them settle / stabilize a couple of hours. At that point they measured:
#1 - OCV: 4.15V - DCIR: 50mΩ
#2 - OCV: 4.15V - DCIR: 50mΩ
(This is a bit lower DCIR than I'm accustomed to seeing w/ protected 18650s, but I'm not complaining. Also note the lack of significant difference in DCIR between ~50% SOC and 100% SOC (which I lack an explanation for at this time.)
I then ran a discharge capacity test at 1.0A to 2.8V Discharge Cutoff. Note that I picked those parameters out of thin air, and do not know what parameters NC uses when specifying their cells. They measured:
#1 - 3715 mAh
#2 - 3706 mAh
These are fresh, and they could both die young for all I know, but no complaints about what I see out of the package. What stands out to me is: Consistency. Where ammunition and lithium-ion cells are concerned, I find consistency reassuring;-) It suggests possibly good manufacturing practices and tight / consistent prodedures at the plant they came from.
Open circuit voltage (OCV) out of the pkg was:
#1 - 3.53V
#2 - 3.53V
Although it's neither good practice nor my usual to measure DCIR at other than full state-of-charge (SOC), I measured these purely for relative comparison of the 2 cells at delivery. DCIR at transport charge was:
#1 - 49 mΩ
#2 - 48 mΩ
I charged them @1A to 4.20V, then let them settle / stabilize a couple of hours. At that point they measured:
#1 - OCV: 4.15V - DCIR: 50mΩ
#2 - OCV: 4.15V - DCIR: 50mΩ
(This is a bit lower DCIR than I'm accustomed to seeing w/ protected 18650s, but I'm not complaining. Also note the lack of significant difference in DCIR between ~50% SOC and 100% SOC (which I lack an explanation for at this time.)
I then ran a discharge capacity test at 1.0A to 2.8V Discharge Cutoff. Note that I picked those parameters out of thin air, and do not know what parameters NC uses when specifying their cells. They measured:
#1 - 3715 mAh
#2 - 3706 mAh
These are fresh, and they could both die young for all I know, but no complaints about what I see out of the package. What stands out to me is: Consistency. Where ammunition and lithium-ion cells are concerned, I find consistency reassuring;-) It suggests possibly good manufacturing practices and tight / consistent prodedures at the plant they came from.
