Samsung INR21700-48X batteries from VapCell

These batteries are neither high-current nor high-capacity, but they caught my interest because they rarely appear in reviews. I thought it was worth filling that gap.

As you can tell from the title, these batteries are sold by VapCell, although in practice its role comes down to putting its own label on the casing. But I’ll get ahead of myself and say that these are genuine branded batteries, which is actually quite rare on AliExpress.

They arrived in two cardboard boxes. Unfortunately, the reviews didn’t say anything about the packaging, so I assume cardboard is the best I can hope for when ordering.


These turned out to be quite rare batteries. Unfortunately, I couldn’t find a datasheet; all I have is a table from a Danish guy’s website and a few specifications from the same source.
Typical capacity: 4800 mAh
Minimum capacity: 4650 mAh
Maximum charging voltage: 4.2 V (4.15 V for cycle life)
Nominal voltage: 3.64 V
Charge method: CC-CV
Charging current rate: 0.33C (1584 mA)
Discharge cut-off voltage: 2.5 V (3.0 V for cycle life)
Cycle life: 3000 to 70%

As you’ve probably noticed, the key feature of these batteries is their cycle life. They’re rated for up to 3000 cycles before capacity drops to 70% of its original value. And judging by the separate recommendations for extending their service life (charging to 4.15 V and discharging to 3 V), cells like these are used in batteries for electric vehicles. What’s more, while looking for information on new Tesla batteries, I came across a reference to the 48X designation. I won’t claim anything for certain, but it did make me wonder.


The product page also had a screenshot from what I assume is their datasheet.


The batteries were manufactured in late November 2019, so they can be considered fairly fresh. There are markings both on the heat-shrink sleeve and underneath it; the markings and manufacturing date are the same in both cases.


Dimensions and weight.


The conditioning cycle was run at a discharge current of 1 A. The measured capacities were 4744 and 4837 mAh; both batteries were initially charged to about 30%.


The recommended charging current for these batteries is 0.33C, or 1584 mA. I used 1.59 A in my test, and charging took 3 hours and 20 minutes. The CV phase was moderate.



Capacity was measured in five modes: 0.2C, 0.5C, 1C, 10 A, and 15 A. According to some information I found, 10 A is the maximum continuous current for these batteries, but I decided to see how they would perform at a higher current.
The best result I got was 4735 mAh, or 17.32 Wh.


Here are the temperatures at 1C, 10 A, and 15 A. The batteries barely warmed up. Even the relatively powerful INR21700-50S reached 50–51 degrees at 10 A, which isn’t much higher.


The test results for the second battery were practically identical.


The same goes for the temperature.


VapCell also tested these batteries at discharge currents of up to 15 A.


The two samples also match closely in their performance at discharge currents of 0.2C, 1C, and 10 A.


The batteries have an impedance of about 12 mΩ, close to that of the Samsung 50G.
Measurements taken on arrival, after the conditioning cycle, and after testing.


And, of course, a comparison with the closest competitors of similar capacity and the same 21700 size.

First, at 0.2C:
1. The batteries under review
2. Samsung INR21700-50E
3. LG INR21700-M50T
4. Samsung INR21700-50G
5. VapCell T50 (INR21700-50S)


And at 10 A, an interesting thing becomes apparent. At low current, the 48X batteries clearly lag behind the others. At 10 A, however, they deliver fewer mAh but are practically on par with the higher-capacity Samsung 50E and LG M50T in terms of energy output.



Conclusions.
In my opinion, these are good, genuine batteries. Their capacity is lower than that of the better-known models shown in the comparison, but their voltage stays slightly higher during discharge. At 10 A, that brings their energy output in Wh into line with the Samsung 50E and LG M50T. The batteries also showed consistent test results, so they should work well in high-capacity battery packs.
Their real continuous discharge current is 10 A, with a maximum of 15 A. But one of their key "features" is their long claimed service life, which makes them useful for electric vehicles.

That’s all from me. I hope this was useful, and as always, I’ll be glad to hear your questions and suggestions.