A couple more Murata US18650VTC6 cells and a comparison with the previous batteries

I won't go into a long account of the purchase this time—just a brief review of a couple of popular VTC6 cells. As a bonus, I'll compare them with cells sent to me earlier by one of my readers and bought from the same store, nkon.


Originally, I wanted to order the red VTC6 cells. I was really curious to see what they were like, but somehow it turned out that “one batch had already sold out, and the other hadn't arrived yet.” I decided not to cancel the order, though, since I planned to use them with a universal converter board, which needs exactly 4 cells.

There's not much to say about them: they're a well-known brand of cells that, in my opinion, are the best in their class. Their closest competitor is the Samsung 30Q. There's also at least the HG2, but it falls a little short of Murata and Samsung. I compared them in my previous review.


Brief specifications.


By the way, for some reason many stores list the maximum continuous current for these cells as 30 A, even though the datasheet gives figures for a discharge current of 20 A.
Also, one store has this description:


In fact, it should probably be read as follows:
Maximum continuous discharge current: 30 A (up to a temperature of 80 °C).


The batteries are marked 25629AAL18M and 25639AAL18M, indicating a production date of December 18, 2018. The previous pair was made on August 27, 2018, so the store is constantly restocking its batteries. It sometimes sells older batteries too, but those are listed separately, with an explicit note that they were manufactured some time ago; the price is usually reduced for such lots.
A unique matrix code is present, confirming that the batteries are genuine.


The batteries also have a double crimp, unlike counterfeits. Photo from the internet.


Dimensions and weight. Interestingly, the previous batteries were slightly lighter (the two photos at the bottom).


"Break-in" run: capacity of about 3200 mAh at a discharge current of 0.5 A and a cutoff voltage of 2.8 V.


I used the same test setup as last time: an EBC-A20 load and a heavy-duty battery holder. This is actually a photo from the previous review.


Testing was carried out under the same conditions as before, at discharge rates of 0.2C, 0.5C, 1C, 2C, 10 A, 15 A, and 20 A, with a cutoff voltage of 2.5 V.
At a discharge rate of 0.2C, capacity was actually slightly higher than the rated 3000 mAh, measuring 3081 mAh.


Above, I mentioned the maximum temperature of 80 degrees, meaning the maximum continuous current is limited by temperature. The datasheet says these batteries can deliver up to 30 A, but in reality they reach that temperature limit at just 15–16 A; at 20 A, the temperature is around 90 degrees.
So 30 A is a current they can deliver for a limited time. More precisely, once the temperature reaches 80 degrees, the load current must either be reduced or the load switched off completely.
Below are three thermal images at 10, 15, and 20 A, showing a full discharge down to 2.5 V.


As last time, because of the confusion in the datasheet, the second battery was discharged to 2.0 V in every mode except 20 A. At this voltage, it delivered over 3000 mAh at currents up to 15 A.


The temperatures are roughly similar, since the discharge times are almost the same.


The batteries' internal resistance at three test points:
1. As received
2. After the first "break-in" run.
3. After all the tests.


For comparison, the resistance of the previous batteries as I received them.


And for comparison, I put the main results together in one graph. The batteries reviewed here are shown in red, and the previous ones in blue. There's a slight difference in capacity, but the previous batteries were tested at the end of March, when it was cooler at home, which may explain the lower results.


The second battery shows essentially the same results. The only difference is that this time I discharged it at 20 A only down to 2.5 V, rather than 2.0 V.
Perhaps it would be worth comparing them in one mode at the same temperature as an experiment.


The pricing is much the same as for the LG HG2 batteries, but in this case the price difference is even more significant. Presumably genuine VTC6 batteries on AliExpress are available here.
For a small quantity, the price is the same as on AliExpress (4 pcs cost $25 at nkon and on AliExpress). But if you need more than 11, the difference is already one and a half times at 12 units: $45 at nkon and $67 on AliExpress. I think that's a significant difference.


Once again, I've confirmed that the VTC6 is one of the best 18650 batteries with a capacity of 3000 mAh. These batteries are genuine, and the price is no higher than on AliExpress.