Vapcell batteries, part five: 18650 size

In today's installment of my VapCell battery review, there won't be a variety of form factors: the whole review is devoted to one size, probably the most popular one, 18650. Even so, I think it'll still be useful.


So, I received four neat branded boxes, each containing a different type of battery. All of these batteries are listed on the website as having been announced in 2020, which made them especially interesting to test.

As for the price, as I understand it, it's higher because a case is included. The case itself costs $5.49 each or $7.68 for a pair — link, but it's best to check before ordering.


Here are today's “test subjects.”





Vapcell K25 18650 2500mAh 20A
Model on the manufacturer's website — link
Model sold individually on AliExpress — link, priced at $9.98 for 1, $12.98 for 2.



Specifications
Model: K25 INR18650 2500mah 20A
Size: 18.3*65.0mm
Nominal voltage: 3.60V
End-of-charge voltage: 4.20V
End-of-discharge Voltage: 2.5V
Typical Capacity: 2500mAh (0.2C discharge)
Min capacity: 2400mAh (0.2C discharge)
Weight: Max:46g
Internal resistance: Max:15mΩ （AC 1kHz）
Standard Charge: 2000mA,CCCV 100mA cut-off
Quick Charge Current: 4000mA
Max Continuous Discharge Current: 20A
Max Discharge Current: 35A

It's somewhere between a general-purpose and a high-drain cell, since its continuous discharge current is 20A, with a maximum of 30A.


The heat-shrink wrap is bright red, and some markings are visible directly on the cells underneath. The wrap lists all the necessary specifications: capacity, as well as continuous and pulse discharge currents.


Dimensions and weight.


A “break-in” cycle at a 1A discharge current showed a capacity of about 2550mAh.


Like many other batteries, it supports two charging modes: normal and fast. For this model, the specified normal charging current is 2A, and a full charge takes 1 hour 25 minutes.


At twice the current, charging time drops to 50 minutes, which is pretty good.


The product page had a test graph that was clearly taken from lygte-info.dk


By chance, I ended up running 9 tests on these batteries instead of the usual 6–7. In total, I tested them at 0.2, 0.5, 1, 2, 3, 4, 6, 8, and 10C, where C=2.5A
I can say that the battery performed excellently right up to 25A, even though its specified maximum continuous current is 20A.


At the rated continuous currents of 10, 15, and 20A, the temperature stayed below 90 degrees, which is perfectly normal too.


The second sample produced almost identical results, so I had no complaints about consistency either.


The temperature was a couple of degrees higher, but that could be explained by a slight change in the ambient temperature.


A current of 25A is the limit for these cells, i.e. higher than the stated continuous rating, and since my EBC-A20 can't handle more than 20 A, I had to use a more powerful load.


But even in overload mode, the temperature was around 100 degrees, which is more or less normal for this kind of operation.


For high-current batteries, I often run one more test: after discharging at the maximum current, I let the battery cool down and then continue discharging at 0.2C to see how much charge is left. The less the result, the better.
In this case, I managed to "pull" another 76 mAh out of it.


Naturally, I wanted some comparison graphs, and this is the list of competitors I ended up with:
Vapcell K25
LG ICR18650-HE4
Murata VTC5A
Samsung INR18650-25R

Note that the HE4 and 25R are mid-range (all-purpose) models, while the VTC5A is a high-current model.
The graph compares four models with the same capacity at two discharge rates—10 and 20 A. Overall, they're pretty similar; the VTC5A is the only one that falls a little behind.



Battery impedance right after arrival, after "conditioning," and at the end.




Vapcell K30 18650 3000mah 15A
Model on the manufacturer's website — link
Model on AliExpress, sold individually — link, price: $9.98 for 1 pc, $12.98 for 2 pcs.


Specifications
Model: K30 INR18650 3000mah 15A
Size: 18.3*64.9mm
Nominal voltage: 3.60V
End-of-charge voltage: 4.20V
End-of-discharge Voltage: 2.5V
Typical Capacity: 3000mAh (0.2C discharge)
Min capacity: 2900mAh (0.2C discharge)
Weight: Max:48g
Internal resistace: Max:15mΩ （AC 1kHz）
Standard Charge: 1500mA,CCCV 100mA cut-off
Quick Charge Current: 4000mA
Max Continuous Discharge Current: 15A
Max Discharge Current: 30A

These are mid-range batteries, rated for continuous currents up to 15 A, but they can handle short bursts of up to 30 A, making them suitable for e-cigarettes and power tools.

The packaging is the same as for the previous batteries; the only difference is the color of the clasp, which matches the battery color.


They're pretty ordinary batteries, except for the five-point positive terminal. I can't even think of another battery in this class that I've seen with one like it; they usually have three or four points.


There's some kind of marking under the heat-shrink wrap.


Dimensions and weight.


The "conditioning" run showed a capacity at the lower end of the stated range.


The nominal charging current is 1.5 A, and the maximum is 4 A. At the nominal rate, charging takes 2 hours and 16 minutes.


In fast-charge mode, it takes 1 hour and 12 minutes, but I wouldn't recommend exceeding a charging current of 2–2.5 A.


These batteries were also tested on a well-known website; I took the graph from the product page.


The batteries were tested at six discharge rates: 0.2, 0.5, 1, and 2C, as well as 10 and 15 A.
The first sample had a capacity of 2940 mAh, against a stated 2900–3000 mAh, so everything checks out. During a prolonged discharge at 15 A, there is a noticeable voltage drop, so I’m skeptical of the claim that it can handle 30 A briefly.


Temperature at 6, 10, and 15 A—all within the normal range.


The second cell, however, turned out to be noticeably worse. At 0.2C, its capacity was 2847 mAh; at 15 A, it was down to 2643 mAh, compared with 2810 mAh for the first cell.


Its temperature was also lower. I think that’s because of its lower capacity—the battery simply didn’t have time to warm up.


Battery impedance right after delivery, after “conditioning,” and at the end.



Vapcell S30 18650 3000mah 25A
Model on the manufacturer's website — link
Individual cells on AliExpress — link, priced at $11.99 for 1 cell and $17.98 for 2.



Specifications
Model: S30 INR18650 3000mah 25A
Size: 18.3*65.0mm
Nominal voltage: 3.60V
End-of-charge voltage: 4.20V
End-of-discharge Voltage: 2.5V
Typical Capacity: 3000mAh (0.2C discharge)
Min capacity: 2900mAh (0.2C discharge)
Weight: Max:50g
Internal resistance: Max:11mΩ （AC 1kHz）
Standard Charge: 2000mA,CCCV 100mA cut-off
Quick Charge Current: 4000mA
Max Continuous Discharge Current: 25A


Here, the color of the case latch also matches the cells themselves, and the cells look almost identical to the K25 model.


The positive terminal has three tabs, but the metal seems rather thin—at least thinner than on the previous two models, even though this cell is marketed as a high-current model. The markings are visible under the heat-shrink wrap.


Dimensions and weight.


During the conditioning run at a 1 A discharge current, I got the rated 3000 mAh, and even a little more.


Since these are high-current cells, the specified standard charging current is 2 A; the maximum is 4 A, just like the previous models.
At 2 A, charging takes 1 hour 38 minutes. Note the short CV phase—that’s good.


At twice the charging current, charging takes just under an hour. The CV phase is noticeably longer, so in my opinion the maximum charging current for these cells is 3 A.


The manufacturer measured the capacity here, and those are the figures I’ll be checking next.


I decided to run a more extensive set of tests, covering these discharge rates and currents: 0.2C, 0.5C, 1C, 2C, 10 A, 15 A, 20 A, 25 A, and 30 A. That’s 9 tests, just like for the K25.
The capacity matches the rating, but at 30 A the voltage starts to sag noticeably, so this really is the maximum. The specified continuous discharge current is 25 A, but since the manufacturer also tested the cells continuously at this current, I decided to do the same.


Temperature under the standard operating conditions—15, 20, and 25 A. The maximum was around 100 degrees, which is rather high, but branded cells reach about the same temperature.


The second cell behaved exactly the same, except in the 30 A test, where it delivered slightly less.


The temperature was about the same.


As with the K25, I also had to test this model using an EBC-A40L load. The manufacturer uses the same kind of load for its tests.


Don’t worry, the tests went fine. It’s just that in the 30 A load test, the first cell exceeded 110 degrees, while the second only reached 106. There’s no doubt that’s too hot, although this is outside the normal operating range.


After it cooled down, I was able to draw another 156 mAh—twice as much as from the K25 model. As I mentioned there, the lower this number, the better.


But the comparative tests are more interesting here. Right from the start, the manufacturer makes this claim (Google Translate):


Pretty good, and bold at the same time. By the way, I should order Samsung's new 25S model for testing sometime.

They even provide comparison graphs



Of the competitors shown in the graph, I don't have the Molicel P26, but I do have graphs for their P28 model, which is even more interesting since it's comparable to Murata's VTC5D.

Unfortunately, I don't have graphs for currents above 20 A, so I'll compare the results at 10 and 20 A.
In this mode, the batteries under review are closest to the VTC6, since the others (P28 and VTC5D) are rated at 2800 mAh to begin with. Even the S30 and VTC6 temperatures were about the same at 20 A.



Battery impedance right after arrival, after “conditioning,” and at the end.



Vapcell F35 18650 3500mah 10A
Model on the manufacturer's website — link
Model sold individually on AliExpress — link, price — $9.99 for 1 pc, $13.98 for 2 pcs.


Specifications
Model: F35 INR18650 3500mah 10A
Size: 18.4*65.1mm
Nominal voltage: 3.60V
End-of-charge voltage: 4.20V
End-of-discharge Voltage: 2.5V
Typical Capacity: 3500mAh (0.2C discharge)
Min capacity: 3350mAh (0.2C discharge)
Weight: Max:48g
Internal resistance: Max:25mΩ （AC 1kHz）
Standard Charge: 1000mA,CCCV 100mA cut-off
Quick Charge Current: 2500mA
Max Continuous Discharge Current: 10A
Max Discharge Current: 20A


Unlike the previous ones, this box has a black clasp and green batteries. Looks like they couldn't find a suitable box—not quite feng shui :)


Rated for 10 A continuous and 20 A short-term discharge. The positive terminal has four contact points and is fairly thick.


Dimensions and weight.


The “conditioning” charger measured capacities of 3386 and 3451mAh at 1 A, which matches the stated specifications.


These are high-capacity batteries, so 1 A is a normal charging current and 2.5 A is fast.
I'll be blunt: charging 3.5 Ah batteries at 1 A takes a long time. No, that's not right—it takes a loooooong time.


Charging at 2.5 A does speed things up noticeably, of course, but I wouldn't recommend going above 1.75–2 A.


Since there are no high-current discharge modes, I didn't run many tests: 0.2, 0.5, 1, 2C and 10 A.
The battery met its stated minimum of 3350mA, though only just, exceeding it by a little with a measured 3374mAh.
It performed quite respectably at 10 A, delivering 3329mAh or 10.53Wh.


Temperature at 7 A (2C) and 10 A. Keep in mind that high-capacity batteries are more “delicate,” so 75 degrees is the upper limit here.


The second sample did a little better, but by only 10–20mAh, which is well within measurement error.


The temperature was also a little higher, but nothing critical.


Battery impedance right after arrival, after “conditioning,” and at the end.



Conclusions

Vapcell K25 18650 2500mah 20A
Decent batteries that meet their rated capacity and perform normally at currents up to 25 A, despite being rated for 20 A. Unfortunately, capacity is only 2500mAh, although there are already options with 2800–3000mAh capacity and comparable specs.
Vapcell K30 18650 3000mah 15A
Honestly, I don't quite get these batteries. Discharge current is limited to 15 A, and capacity is 3000mAh. Sure, they meet the specs, but it feels a bit underwhelming. Also, I didn't like that the two samples had different characteristics, both in terms of capacity and impedance.
Vapcell S30 18650 3000mah 25A
Pretty good cells, with good consistency. They can deliver 25 A continuously and easily handle 30 A for short periods, possibly more. But again, in practice I didn't find any major differences from the VTC6, although the positive terminal clearly shows these aren't VTC6 cells.
Vapcell F35 18650 3500mah 10A
A high-capacity model, somewhat similar to the LG INR18650-MJ1, but it falls short in terms of usable capacity. So I'd probably consider it equivalent to the Samsung INR18650-35E.

In short, these are decent batteries, and almost all of them meet their specifications (the second K30 sample fell short), but they didn't exactly impress me. Essentially, they're equivalent to (and possibly even original versions of) cells from well-known manufacturers, just in nicer packaging. Speaking of the packaging, I liked the heat-shrink wrap: it held up fine even at 110 degrees and didn't come loose like the wrap on Litokala, Varicore, and similar brands.

That's all for now. I hope this information was useful, since these batteries can be found not only on AliExpress but also in local stores.