Another batch of batteries, this time counterfeit SONY VTC6 cells

A friend spotted some Sony VTC6 batteries on AliExpress, so we decided to give them a try. Some were for him, and I ordered four for myself to test.
Long story short, it’s not looking good. More in the review.


People often ask me where it’s best to buy batteries. Oddly enough, probably offline, but people still turn to AliExpress to save money. That’s what we did this time. The reviews were decent, and the price was higher than usual ($12.84), which, along with the claim that they were genuine, gave us a little hope—maybe these would be the real deal.

We placed the order and got them: my four and my friend’s twelve.
No complaints about the packaging: neat and secure.


They have markings, and the overall finish is pretty neat. At first glance, nothing to complain about.


According to the datasheet and the markings on the batteries, they were made on:
Y — 2016 (Z is 2017, so the letters should then start over with A-B-C)
E — May
14 — day of the month.


Dimensions, and the weights of the heaviest and lightest of the four.


By the way, one battery is already underweight. The datasheet says 46.6 +/-1.5 g; 44.6 g is already 2 g below that.


And, as usual, the first test is in a universal charger—especially since its discharge current is close to the 0.6C test rate, at 0.5 A instead of 0.6 A.
Well, that was completely unexpected. I know clones and counterfeits are out there, of course, but this is incredibly brazen... The seller claims 3000 mAh and “Original Japan.”


The second thing I wanted to check was the battery’s internal resistance. For that, we turn to the datasheet again, which specifies 8–18 mΩ. For comparison, my VTC4s, which are over two years old, measure around 13–14 mΩ.


We connect the meter and see that, although the readings are fairly consistent, the resistance is clearly too high. That means you’d better not ask these batteries for the promised 30 A, since that could lead to excessive heating.


Now I tried to take a closer look at the markings—or rather, compare them with genuine VTC4s. By the way, I usually bought my genuine ones from Gearbest. Over the years, I came across one counterfeit, but after I contacted them, they took it off sale and apparently replaced it with a genuine one.

The font is larger and blurry. The genuine one is at the top; you can make out the “dot-matrix” pattern in almost every character.


A slightly different angle and lighting.


We connect the battery to an electronic load, using a proper four-wire connection in this case.


Since these batteries are suspicious, I decided to limit the current to 10 A, even though the VTC6 datasheet specifies capacity at 15 A as well.


But first, let’s test a couple at 0.2C, or 600 mA.
Battery No. 3 delivered a total of 2185 mAh, or 8.025 Wh, when discharged to 2.5 V.


The fourth delivered even less: 2129 mAh, or 7.814 Wh.


At 10 A, the first battery delivered 2141 mAh, or 7.072 Wh.


At the same 10 A, the second delivered about the same: 2120 mAh, or 7.035 Wh.


At 3 V and 10 A, the temperature reached 65 degrees. Right at the end of the discharge, at 2.5 V, it was already 68 degrees.


By comparison, genuine VTC6s delivered almost 3 Ah in a similar test, well above the 2700 mAh minimum specified in the datasheet.


And although they heated up to the same temperature, it took them almost one and a half times longer, which points to better performance.


That’s about it.
Judging by their capacity, the marking font, and their resistance, these batteries clearly aren’t VTC4s. But their resistance is one and a half times higher than normal, while their capacity is one and a half times lower, and I can’t say what kind of batteries they actually are.
You can use them, of course, but I’d look for something better.
Also, the batteries are at the lower end of the datasheet weight range, and they’re slightly longer and thicker than genuine VTC4s, which is a bit odd too.