VapCell 26650 batteries with a capacity of 4200 mAh and a current of up to 32 A

The relatively uncommon 26650 form factor, a capacity of 4.2 Ah, and a current of up to 32 A—that's what today's review is about. As it turns out, these batteries are pretty decent, but as always, more details after the jump.


Yes, there are still quite a lot of 26650 batteries around, but for some reason they're gradually disappearing. The big brands have stopped making them (or almost stopped), leaving this niche to various Chinese manufacturers, with mixed results so far.

Today I'll be looking at some 26650 cells wrapped in heat-shrink tubing with the VapCell logo.

They arrived in a branded box, so I assume that's how they're sold, although I couldn't find 100% confirmation. They're not exactly cheap, and unfortunately the 1/18 coupon can't be applied since the pair costs 17.98. On the other hand, you can save a little when buying more than 3.



Specifications from the VapCell website.
Model: INR26650 4200mah 32A
Typical Capacity: 4200mAh (0.2C discharge)
Min capacity: 4100mAh (0.2C discharge)
Nominal voltage: 3.60V
Max Continuous Discharge Current: 32A
End-of-charge voltage: 4.20V
End-of-discharge Voltage: 2.5V
Weight: 95g ( Appr)
Internal resistance: 11mΩ ( Appr)（AC 1kHz）
Standard Charge: 2000mA,CCCV 100mA cut-off
Quick Charge Current: 3000mA

These are high-drain batteries, since they can continuously deliver up to 32 A. They also have a capacity of just 4.2 Ah despite their 26650 size.

The positive terminal is flat, and the casing has all the basic information you need. The batteries were wrapped in clear film.


The dimensions are fine, but the weight is slightly below the stated value.


The conditioning cycle at 1 A yielded 4164 mAh for the first cell and 4495 for the second. That's a bit too much variation for normal manufacturing tolerances, so we'll check again with separate tests later.


Two charging modes are specified: standard charging at 2 A and fast charging at 3 A. The difference seems rather small for a fast mode, and 3 A is a fairly low current for high-drain cells in general.

At a charging current of 2 A, the first cell took 2 hours and 19 minutes to charge. The CV phase isn't particularly short for a cell designed for high current.


At 3 A, charging took 1 hour and 40 minutes, which is perfectly fine.


The test was conducted in eight modes, at discharge currents of 0.2C, 0.5C, 1C, 10, 15, 20, 25, and 32 A.
The first cell delivered its rated 4200 mAh. Note that the capacity delivered in mAh is almost independent of the load current; this effect is usually related to capacity changing with temperature.


Surprisingly, the temperature wasn't all that high. Here are the results at load currents of 20, 25, and 32 A.


The second cell, however, really does have a higher capacity, with a difference of about 5%. It's not huge, but it's noticeable.


This battery runs hotter, partly because of its higher capacity: the discharge takes longer, so the battery heats up more.


For the sake of experimentation, I measured the remaining capacity after discharging at 32 A, letting the batteries cool to room temperature, then discharging at 0.2C. Both batteries gave roughly the same result: 144 and 148 mAh.


And here's a comparison of the two cells at 0.2C, 10, 20, and 32 A. You can see that the second cell has a higher capacity. Most often, this can be caused by one of two things: the cells are simply different, or the manufacturing process isn't well controlled.
Since the batteries were visually identical and behaved the same way when discharged under different conditions, the most likely culprit is an inconsistent manufacturing process.


Battery impedance after delivery, after the initial run-in, and at the end.
Interestingly, the second battery was warmer, even though its impedance was lower.


I found an interesting image on the VapCell website. A simplified translation of the text reads: “No worse than Golisi, iJoy, and Aspire 4200–4300 mAh,” followed by a graph showing energy output in Wh versus load current when discharged down to 3.2 V.


Unfortunately, I don't have any batteries from the brands listed, but I do have one model from Basen with the same dimensions and a comparable rated capacity (4500 mAh).

Since the batteries under review have different capacities, I made a slightly different comparison: I plotted the results for the first and second samples (blue and red) alongside one of the tested Basen BS26003 batteries (green), since they had the same capacity.
Results at 1C and 20 A. As you can see, although the Basen delivers comparable capacity, it falls behind in energy output and also has a noticeable voltage sag, especially at 20 A.


But after the 25 A test, and especially after the 32 A test, a quirk of the Chinese heat-shrink tubing became apparent: unlike the branded stuff, it starts coming off when heated to around 80–100°C.


I'll keep the conclusions brief. These batteries could be called decent if not for a few issues: noticeable variation in their specs, which makes them less convenient to use in battery packs, and heat-shrink tubing that's so thin it keeps trying to come off.

On the other hand, both batteries delivered what was promised on the product page, so it wouldn't be fair to criticize them too harshly—especially since the variation in capacity is in their favor, not against them.

That's all. I hope you found this review useful.