Liitokala HG2 battery, or how Chinese sellers rip you off, part 2

After my review of a Chinese VTC6 battery clone, one of the readers asked me to test another battery. This time, though, it was sold under the Liitokala brand and labeled HG2—a name and appearance similar to those of another very well-known battery, the LG HG2.
The reader ordered one battery to be sent to my address as a sample (many thanks to him for that). I received it and ran a few tests, which I hope will help us figure out what this battery really is.


It was delivered by Meest Express. At the branch, they handed me a small yellow envelope that I think many buyers will recognize. The battery was inside a little bag. Batteries of other brands from this store have arrived in exactly the same kind of bags, but I usually ordered several at a time, so they came in a box. For obvious reasons, things were simpler this time.


I’ve left out the temperature ranges from the main specifications listed by the manufacturer, since they’re not relevant here. Taken from here.


There’s also a second version of the description — link
This one puts more emphasis on the battery’s internal resistance, a parameter that often makes it relatively easy to tell whether a battery is genuine.


The finish is very neat. The only thing that seems to distinguish it from the genuine article is the Liitokala label.


The dimensions and weight are exactly as stated in the datasheet—spot on.
And here’s a sign that it’s a fake: internal resistance above 30 mΩ, whereas the genuine battery is specified at no more than 17 mΩ, with a typical value of 14–16 mΩ. In other words, this sample’s resistance is twice that of the genuine battery.


The obvious next question is: how can you tell a fake from a genuine battery without any instruments? Basically, you can’t.
You’ll find advice online to check the positive terminal. That can help, but not always—especially since the Chinese manufacturers aren’t fools and try to choose models that look similar.
1, 2. Genuine battery on the left, clone on the right.

Another recommendation is to compare the codes: they shouldn’t be identical. More precisely, if they are identical, the batteries are probably fake. The problem with this method is that you need at least two batteries. I only have one, so I can’t check it this way.
3, 4. Genuine battery on the left, clone on the right. And yes, the codes in the left-hand photo are identical.


You might say that mine is a clone too, but that’s not actually the case. Here’s a photo of three batteries I got my hands on a couple of years ago. The third battery has a different code. So if you got the two shown above, you might conclude that they’re fake too.
Another tip is to check the seam in the heat-shrink wrap; on genuine batteries, it’s almost invisible. But the seam on the battery I’m reviewing is almost invisible too, and without experience it’s very hard to know what it should look like. You need a sample to compare it with.


So the only reliable way is to take measurements.
I showed the battery’s internal resistance above. Now I’ll check its capacity.
First, I’ll put it in a basic charger for an initial run.
1. The battery arrived noticeably discharged. On the first charge, it took about 2200–2300 mAh. The photo was taken while it was charging.
2. Discharged at 500 mA, it delivered 3089 mAh—not bad at all.


Next, I connect the battery to an electronic load.


The first test is at 0.2C, the discharge rate used for the rated capacity of 3000 mAh.
As usual, I discharged it to three cutoff voltages: 3.0, 2.8, and 2.5 V. The manufacturer specifies capacity at a discharge cutoff of 2.5 V, so let’s see what we got.
2865+100+67=3032 mAh, or 11.05 Wh.
No issues here: the capacity in both Ah and Wh matches the LG HG2, which is rated at 3000 mAh and 11 Wh.


The next test is a little more demanding: the discharge current is 10 A, although that’s nowhere near the maximum current.


The cutoff voltages are the same as before, and we’ll calculate capacity at 2.5 V.
2393+320+244=2957 mAh, or 9.62 Wh. The genuine battery is rated at 2925 mAh or 9.8 Wh.

And here, too, everything seems more or less fine. But I should mention that after testing with a proper holder, I found that at high currents my load overstates the result by about a couple of percent because of heating. It’s not much, but it’s there, so the actual difference is greater.


Temperature during the 10 A test, with the battery at 3 V, just before cutoff, i.e. at 2.5 V.
LG HG2 cells were never particularly “cool-running,” but 73 degrees at the very end of the test seems a bit much to me.


Judging by the tests above, 10 A is a discharge current the battery can handle without problems, but I decided to load it at 15 A.
To do this:
1. I got an electronic load and a new holder. I connected the holder’s power contacts to the load input and its sense contacts to a multimeter. The load needs modification for a four-wire connection.
2. I reset the mAh counter, applied a 15 A load, and measured the difference between the voltage reported by the load (including the voltage drop in the wires) and the actual voltage measured at the battery terminals.
3. I stopped the discharge and set the cutoff voltage to 2.2 V, accounting for the 0.3 V correction.
4. Since the mAh counter can only be reset manually, I continued the test with the data accumulated earlier.
5. At 3 V, the discharged capacity was 1827 mAh.
6. The total capacity when discharged to 2.5 V came to 2781 mAh; the manufacturer specifies 2913 mAh for this discharge mode.


Heat. This is where the high internal resistance really showed itself—I even had to interrupt the test.
1. When discharged to 3 V, the battery heated up to 87 degrees. In reality, the temperature would have been a little higher, since I briefly interrupted the test at the very beginning while entering the correction.
2. Since I didn’t want to completely kill the battery, I stopped the discharge at this point and let it cool down.
3. Then I continued the test, discharging it to 2.5 V. Even with the cooldown in between, the temperature climbed to almost 80 degrees again.


For comparison, here’s a discharge test of an original battery. This time the discharge ran without pauses and I didn’t apply any correction, but the wires are short, so the difference is much smaller—not 0.3 V, but 0.1 V. That means the actual cutoff was 2.6 V, not 2.5 V as shown on the display.
But even under these conditions, the battery:
1. Delivered more: 2849 mAh. If it had been discharged to 2.5 V instead of 2.6 V, I think it would have reached the 2900 mAh in the datasheet.
2. Heated up less, reaching 79.5 degrees after an almost complete discharge with no pauses.


So what kind of battery is this, really? There are several possibilities, mainly:
1. Some Chinese-made version. But finding one with a similar positive terminal would be quite difficult—unless they make them specifically for this purpose, in which case it really is a counterfeit.
2. A genuine branded battery, but with lower specs.

The second option is more likely. There’s no need to fake much about its appearance: take a similar battery, remove the original heat-shrink sleeve, put on a new one, and you’ve got a new set of specs.

For example, there’s the LG INR18650 MG1 battery—datasheet
Apart from the color of the heat-shrink sleeve, there are no visible differences: same size, weight, and positive terminal.


Even the capacity is roughly similar. And since specs are usually listed “with a bit of headroom,” it’s very close to what I measured.
The only catch is that these cells are rated for currents up to 10 A and have an internal resistance of up to 35 mΩ. Again, my results were about the same: above 10 A, they overheat badly (the HG2 is rated for continuous discharge up to 20 A). The resistance is also about the same, at 30.6 mΩ. Manufacturers tend to quote this spec conservatively, too: the original HG2 is rated at 17 mΩ, with a typical value of 14–16 mΩ.


So the scam is simple:
1. Take a branded battery (most likely) that has the right capacity and the same external features as the one you want to pass it off as.
2. Remove the heat-shrink sleeve, put on a new one, add your own label, and list the capacity and model—but not the manufacturer.
3. You end up with a battery that has better specs.
4. Profit!

Why does this usually go unnoticed?
1. People only check the capacity, and that matches.
2. They simply don’t use the battery “to the max,” so they don’t notice the difference. For example, put one in a cordless drill and it’ll work—just with a little less torque and runtime, and a bit more heat. But since it’s usually used for short bursts, you won’t notice.

In most cases, measuring the battery’s internal resistance is enough. If it’s clearly too high, it’s 100% counterfeit. If it’s within spec, measure the capacity; it will most likely be lower, as happened with my VTC6.
If both the resistance and capacity are about right, it’s most likely some “Chinese” battery, and you’ll probably just get fewer charge cycles out of it.

That’s why I recommend getting an internal resistance tester if you often work with batteries—it’ll save a lot of time and make testing easier. For example, the YR1030 or YR1035. A cheaper option is the ZH-YU ZB206+ ($9 without the case and fan 9 dollars, or $20 complete 20 dollars). The difference from most chargers is that the devices listed above measure resistance using AC and have a four-wire connection. Household chargers, including various Opus, Liitokala, Imax and others, do not.
One correction: the ZH-YU ZB206+ measures using pulsed current rather than AC, but in my opinion it is still more accurate than measuring with DC. I ordered one to test; when it arrives, I’ll compare it with my meter.
Unfortunately, there’s a good chance AliExpress support won’t accept the measurement results, since they usually rely on the more straightforward capacity measurement.


That’s about it from me. I hope this information was useful, and thanks again to wadikpinsk for sending me the battery sample.