Vapcell F14 batteries, 1400 mAh and 3 A in 18350 size

I've already reviewed Vapcell 18350 batteries, but those were relatively high-current cells, while these are designed with capacity in mind, so the current is limited to 3 A.
Inspection, tests, conclusions.


Although the 18350 form factor is noticeably outdated, there aren't many alternatives for compact devices, such as small flashlights. Unfortunately, batteries of this size from well-known brands are hard to find, so Chinese manufacturers dominate this market, and today I'll be looking at one such option.
I've already reviewed two cells of this size: the first was from Trustfire and performed poorly; the second was from Vapcell and did noticeably better.

As usual, I ordered a pair. They came in a standard plastic box with the Vapcell logo.


Specifications from the Vapcell product page
Model: F14
Size: 18.3*35.0mm
Typical Capacity: 1400mAh (0.2C discharge)
Min capacity: 1350mAh (0.2C discharge)
Nominal voltage: 3.60V
Max Continuous Discharge Current: 3A
End-of-charge voltage: 4.20V
End-of-discharge Voltage: 2.5V
Weight: 26g ( Appr)
Internal resistance: 65mΩ ( Appr)（AC 1kHz）
Standard Charge: 500mA,CCCV 100mA cut-off
Quick Charge Current: 1000mA

Judging by the size/capacity/maximum-current ratio, these are high-capacity batteries. In 18650 size, they'd be equivalent to 3200–3400mAh cells.


Like some other high-capacity Vapcell batteries, these are wrapped in green heat-shrink tubing. As with most others, the casing also has discharge specifications and a code for checking authenticity.
The positive terminal is flat.


By the way, while preparing this review I noticed that the stamped pattern on the positive terminal resembles that of the Vapcell P30, while its shape and number of spokes are like those on 18650 LTO cells.
Of course, that doesn't mean anything; I just happened to notice it.


Dimensions and weight.


The batteries were initially charged to about 60–65%. During the "normalization" cycle, I got around 1400mAh, with almost identical results from the first and second cells.


Two charging modes are specified: standard at 0.5A and fast at 1A.
At 0.5A, a full charge (after a full discharge at 0.2C) took almost 3 hours, which is very good considering the 1400mAh capacity.


At 1A, though, the battery clearly has a harder time: the CV phase is prolonged. So with high-capacity cells, it's best to avoid high charging currents; I'd keep it around 0.5–0.7A.


Vapcell's website has a screenshot of a test at 0.5, 2 and 4A, where the capacity delivered at 0.5A was around 1450mAh. But, as I've written several times, testing at these settings with an EBC-40L tester isn't entirely accurate: its measurement error increases at low currents.


I used an EBC-A10H battery tester. The test rates were 0.2C, 0.5C, 1C, 3A and 4A.
Although the manufacturer specifies a maximum continuous current of 3A, the batteries turned out to work perfectly well at higher currents too, so I decided to expand the test a little.

Capacity delivered at 0.2C was 1401mAh (5.083Wh).


Temperature at 3 and 4A.
Although the manufacturer specifies a maximum continuous current of 3A, the batteries turned out to work perfectly well at higher currents too, so I decided to expand the test a little.


The second cell delivered a result at 0.2C that differed by just 1mAh, which is excellent.


The temperatures were also almost identical.


And of course, a check of how closely the specifications match—one of the most important comparisons in my view, as it helps assess the overall quality of the manufacturing process. The comparison was performed at currents of 0.2, 1C, and 4 A.
There were no complaints here either; a small difference showed up only at the maximum current.


Battery impedance at 1 kHz after arrival, after “normalization,” and at the end.
The results are highly consistent here as well.


Conclusions.
The batteries not only met their stated specifications, but also showed good consistency in those specifications, at least between the two test samples.
The only real drawback is the price: in a listing with free shipping, they come to $6.50 each, not including the cost of the box.
On the other hand, there aren't many 18350 batteries with a genuine capacity of 1400 mAh, and 18350 prices aren't exactly known for being generous, so perhaps it's not all that bad.

In any case, I liked the batteries themselves. That's all from me; I hope this was useful.