Batteries: counterfeit or genuine? How it happens
Not long ago, a friend asked me to do something like an inspection of four 18650 batteries he’d bought at our local market. They were being sold as genuine, but he had his doubts and decided to check. So I decided to put together a short article based on this, with some real-world examples.
So I ended up with four batteries: one LG HG2 and three Samsungs—30Q, 26H, and 22P. There were actually five or even six batteries, depending on how you count them, but I’ll talk about the others separately at the end of the article.
To keep things simple, I’ll start with the LG battery.
The battery is marked LGDBHG21865, with the code Q154F032A3.
Decoding the marking tells us it was made in 2017, on the 154th day of the year, around late May or early June. But if you enter this marking into Google, you’ll see it has already turned up before—and those batteries were bought from FastTech.
What does the matching code tell us? At the very least, that the batteries came from the same batch. We could assume it’s a coincidence; theoretically, that’s possible, though in practice it’s almost impossible.
The positive terminal has four spokes, while the negative terminal is smooth.
Datasheet for the genuine LG HG2.
Dimensions and weight are hard to challenge here, since even the datasheets give these figures with fairly wide tolerances.
Internal resistance: the datasheet gives a typical value of 17 mΩ; the actual value is 14–16 mΩ. The battery I received measured almost 19 mΩ, clearly higher, which is another point in favor of it being counterfeit.
Another way to tell is by the shape and number of “spokes” on the positive terminal.
On the left is a Litokala battery supposedly sold as an HG2; its positive terminal has four spokes. On the right is the one I received, with three spokes.
The genuine LG HG2 has four spokes on its positive terminal. Litokala chose a battery for its version that looks more like the genuine one, although it isn’t genuine either. There’s no need to say much about the one under review: this third difference also shows that it’s counterfeit.
The fourth test is a capacity measurement. The genuine battery should be close to 3000 mAh. At a 1C current, I measured 2640 mAh; at 10 A, it was 2620 mAh—clearly less.
The fifth method is to check how much the battery heats up.
The load current is 10 A. The battery under review is on the left, and the Litokala copy is on the right. The result is identical: 74 degrees.
And now, the test results for a genuine LG HG2.
At a discharge current of 1C and a cutoff voltage of 2.5 V, its capacity was 2880 mAh, or more than 10 Wh (the counterfeit managed 9.3 Wh).
It also heats up noticeably less under a heavy load: 79 degrees, but at 15 A rather than 10 A. Unfortunately, I can’t properly test and compare genuine batteries right now, so I have to rely on results from older tests, which were far from perfect. Still, I think the difference is clear.
To sum up: -
1. Code — presumably counterfeit, possibly copied from batteries sold by FastTech.
2. Resistance — 19 mΩ instead of 14–17 mΩ.
3. Positive terminal — three spokes instead of four.
4. Capacity — 2640 mAh instead of 2880–3000 mAh.
5. Heating — 74 degrees at 10 A; the genuine battery reaches roughly the same temperature at 15 A.
Conclusion: 100% counterfeit.
Now for the Samsungs. My introduction to them began when one of the batteries turned out to be discharged to 1.3–1.4 V—a state you don’t see with genuine batteries, even after long-term storage. But I'll come back to this battery later.
My favorite INR18650-30Q cells all look pretty neat on the outside.
And here's the datasheet.
The positive terminal has three prongs, but they're rather large....
The dimensions and weight differ slightly from the cells I tested earlier, but that alone doesn't prove they're counterfeit.
The resistance is 20 mΩ; the datasheet gives a typical value of 13 +/-2 mΩ. The actual value was 12.9, so this is already a bad sign.
The positive terminal is different too. The original is on the left, the one under review is on the right. I think the difference is obvious.
The markings are a separate issue here.
There seems to be no visible difference; they're practically identical, with one small exception...
Samsung batteries have their production date printed either on the heat-shrink sleeve below the SDI abbreviation, or underneath the sleeve if that spot is blank.
Here, the heat-shrink sleeve is not only brighter and prettier, it also has no production-date marking. The original is below. If you look closely, you can see faint marking characters on the left that are missing from the one under review, which clearly indicates it's counterfeit.
In the 1C and 10 A tests, the battery delivered 2660 and 2700 mAh, respectively.
Comparing the results for the original (green and orange) with the one under review (red and blue), you can see that not only the capacity differs, but also the shape of the discharge curve. At the higher current, the counterfeit delivered slightly more capacity than at the lower current; with the original, it's exactly the opposite.
This is most likely due to the higher temperature during discharge, which in turn is caused by the higher internal resistance.
Counterfeit on the left, original on the right; discharge current is 10 A.
To sum up -
1. Code - no production-date marking
2. Resistance - 20 mΩ instead of 12-14
3. Positive terminal - larger contact area
4. Capacity - 2660 mAh instead of 2970-3000 mAh
5. Temperature rise - 76 degrees at 10 A; the original reaches 56 degrees at the same current.
Conclusion - 100% counterfeit.
The third battery is an ICR18650-26H. I haven't had one of these before, which makes figuring out whether it's counterfeit all the more interesting.
The production date is printed on the heat-shrink sleeve: TGQ1 with the SDIEM code. So I looked online for a date-code calculator, which gives a production date in early March 2016.
The datasheet for this battery series.
The positive terminal has five prongs and a fairly large central pad. The battery weighs 2 grams less than specified in the datasheet.
The resistance measured 48 mΩ, but it's hard to judge here because the datasheet specifies less than 100 mΩ, so technically it seems fine.
Since I hadn't come across these batteries before, I had to visit another site to find a photo of an original. It turns out the original should have six prongs on the positive terminal, not five, and the shape itself is quite different.
Interestingly, our online stores sell the same counterfeit with the same positive terminal as an original.
But what if I'm wrong and this is an original? Let's measure its capacity.
At 1C and 2C, I actually got 2486 and 2319 mAh, which is, in fact, consistent with the original, which should deliver at least 2340 and 2080 mAh.
And here I'll explain another aspect of testing. Someone once asked me why we need all these graphs when it's enough to simply measure capacity. The thing is, each type of battery has its own “signature”—characteristic “humps” and “dips”—and by comparing two graphs, you can tell with fairly high accuracy whether a battery is original or counterfeit. Of course, that only works if you have a discharge graph for an original battery to compare it with.
I took the discharge graph for an original Samsung 26H from the site mentioned above and compared it with my results.
First, the one under review, at discharge currents of 1C and 2C.
And the original.
Unfortunately, this person doesn't test using the standard C-rate sequence of 0.2C, 0.5C, 1C, 2C, etc., but instead uses 0.2 A, 0.5 A, 1.0 A, 2.0 A, etc. which, in my opinion, is wrong, but there it is.
Above, I chose colors that roughly match the colors of the graph for the original cell at 3.0 A and 5.0 A; in my test, these correspond to 2.6 and 5.2 A.
Two things stand out:
1. The original’s voltage drops much more sharply at the end of the discharge.
2. At 5 A, the original battery delivered more capacity than at 3 A; the one under review did the opposite.
3. In all the tests, capacity was above 2500 mAh. In my tests, both results were below 2500 mAh, and at 5.2 A it was only about 2300 mAh.
At a current of 5.2 A, the temperature reached almost 60 degrees.
Yes, this was a difficult case, but still:
1. Code — the date code is decoded correctly.
2. Resistance — within the datasheet specification.
3. Weight — 2 grams less than specified in the datasheet.
4. Positive terminal — five spokes instead of six on the original; the terminal itself is also shaped differently.
5. Capacity — 2319 mAh at a 2C discharge rate, instead of 2500–2550 mAh.
6. Discharge curve — less steep; at 2C, the cell under review delivers only 7.5 Wh, compared with 8.6 Wh for the original.
Conclusion — 100% counterfeit.
Now I’ve reached the battery that arrived almost completely discharged: the Samsung ICR18650-22P.
Its voltage was only 1.3–1.4 V, which should never happen with a normal (genuine) battery. Either it was stored who knows how, or it has a very high self-discharge current. My normal batteries can sit around for a couple of years and still retain their charge—not 100%, perhaps, but certainly not "dead flat".
First check: date of manufacture. The battery is marked 5ES2 with the code SDIEM, which corresponds to around mid-May 2014. If it’s genuine, then wow—it’s almost a collector’s item. This battery is 5 years old.
Datasheet for the original ICR18650-22P.
The positive terminal has three spokes and a small diameter. Its dimensions roughly match the datasheet, but its weight is 45.24 grams, which is above the datasheet’s maximum of 44.5 grams.
Resistance is 20 mΩ, which is actually pretty good—the datasheet specifies no more than 35 mΩ. But look at the voltage!
I put it on charge, and 1960 mAh went into the battery. I had to restart the charging process several times because at first the charger thought it was a nickel-based battery and stopped charging.
The resistance didn’t change, which once again shows that when measured correctly using AC, resistance is almost independent of the battery’s state of charge.
The shape of the positive terminal differs both from other Samsung batteries and from the original shown on this page of the test.
The key difference is the shape of the "spokes": on the original, they narrow near the "button"; on the one under review, they’re a little straighter. I’ve marked the area to look at in the photo. The difference is small, but it’s there.
Also, the diameter of the "button" is slightly larger than on my original cells, and its surface is rougher. But since these are different batteries, I can’t use them as a reference.
At discharge rates of 1C (2 A) and 10 A, I measured capacities of 1995 and 1857 mAh.
The discharge curve is very similar to that of the original battery. The only difference is that the original had a capacity of about 2050–2100 mAh in these same test conditions, rather than 1995 and 1857 mAh, and its capacity was the same at both discharge rates.
Energy capacity was 7.4 and 6.6 Wh; for the cell under review, it was 7.2 and 6.15 Wh, respectively.
There was also a test at 5 A, but unfortunately all that remains is the thermal image. In that test, the battery heated up to 61 degrees, so I decided to test it at 10 A instead (second photo), where the temperature rose to 77.5 degrees.
In my opinion, this was the most difficult test.
1. Code — the date code is decoded correctly.
2. Resistance — within the datasheet specification.
3. Weight — 0.75 grams above the datasheet maximum.
4. Positive terminal — very similar to the original, though with some minor differences.
5. Capacity — 1857 mAh at 10 A, instead of 2050–2100 mAh.
6. Discharge curve — very similar to the original.
Conclusion — very likely genuine. There are some minor differences, but if the battery really is 5 years old and was stored carelessly—as suggested by its 1.4 V voltage and high self-discharge current—the test results could well be as shown in this review.
The only things that point most strongly to it being different from the original are the slightly different shape of the positive terminal and its somewhat higher weight. But in any case, I wouldn't buy these batteries, precisely because there's no way to know how they've been stored all this time.
A few comparison photos.
My original batteries are on top, the ones under review are below.
The original 30Q is on top, the ones under review are below. The difference in the color of the pink heat-shrink tubing is especially noticeable: the clones have a more saturated color.
You can also compare the shape and appearance of the crimping around the positive terminal, but for an accurate comparison it's sometimes best to have an original in hand, since photos don't always show the details.
Positive terminals: originals on top—30Q, 35E, 20S; the ones under review below—30Q, 26H, 22P.
And this is a bonus track: another INR18650-30Q, a couple of which came my way earlier.
These batteries are textbook examples of a “typical fake,” and the heat-shrink tubing has even started peeling off one of them.
The two batteries have completely identical markings, but different positive terminals!
By the way, about the markings: they should be under the heat-shrink tubing. On the pair of originals (left), you can just about make them out, while the ones on the right have none. The key point is that the heat-shrink tubing has no date code. If you see a battery missing one of the codes, it's 100% fake.
Two original 30Qs on the left, two fakes on the right. No further comment needed...
Even so, one battery had an internal resistance of 18.6 mΩ, about the same as the first 30Q I showed above. The second was nearly 33 mΩ, with a voltage of just 1.8 V.
Despite all that, capacity was only 2650–2700 mAh, but it barely changed at discharge currents of 3, 6, and 10 A—and actually increased as the current went up.
Battery temperature at discharge currents of 6 and 10 A. The original reaches 56 degrees at 10 A, compared with 74 here.
All in all, it's a fairly decent clone, with a maximum current of 10 A and slightly lower capacity. They strongly reminded me of the difference between original LG HG2 batteries and their clones—the results are much the same.
But what really shocked me was the second battery in the pair. This is what it looks like after sitting around at a friend's place for about 8–10 months. I tried charging it; it seemed to be charging, but then I thought, why bother? I just removed the heat-shrink tubing, because this thing can't be used—it has to be recycled.
And here's my friend, who sells batteries, taking apart a fake “battery” from a power bank bought on AliExpress. As they say, it's both funny and tragic...
So, what can we conclude?
Popular battery models are the most frequently counterfeited. In this case, that's the “chocolate bars”—LG HG2 and Samsung 30Q. The ICR18650-26H shown here also clearly looks fake, but the ICR18650-22P is less clear-cut. If you overlook the slightly different terminal shape and weight, you could say it behaved like a genuine battery that had spent five years forgotten in some far corner of an unheated, uncooled warehouse. Besides, it's not a very common battery, so it's less likely to be counterfeited.
If you've bought batteries and aren't sure they're genuine, you can usually check a few things:
1. Whether they match the datasheet—for example, battery weight, capacity, and internal resistance.
2. If you have several batteries, their internal resistance should be almost identical. Clones usually vary from one unit to another.
3. The shape of the positive terminal. Clones often look very different.
4. The discharge curve should match the original—literally “one-to-one.”
5. The markings, especially the date code. Some manufacturers (SonyMurata) use a unique code for each battery, while LG uses one for the whole batch, and even then the odds of buying two with the same code are actually pretty low.
6. If everything looks right but you're still unsure, ask someone who can help, at least in the comments under this article.
7. If you bought the batteries on AliExpress, there's a 99% chance they're fake. You can buy them on Taobao; they have some fairly decent Chinese-made batteries without famous brand labels. At least that's not a scam where they can pass off anything as Samsung.
That's all from me. I hope this was useful, and as always, feel free to ask questions.
So I ended up with four batteries: one LG HG2 and three Samsungs—30Q, 26H, and 22P. There were actually five or even six batteries, depending on how you count them, but I’ll talk about the others separately at the end of the article.
To keep things simple, I’ll start with the LG battery.
The battery is marked LGDBHG21865, with the code Q154F032A3.
Decoding the marking tells us it was made in 2017, on the 154th day of the year, around late May or early June. But if you enter this marking into Google, you’ll see it has already turned up before—and those batteries were bought from FastTech.
What does the matching code tell us? At the very least, that the batteries came from the same batch. We could assume it’s a coincidence; theoretically, that’s possible, though in practice it’s almost impossible.
The positive terminal has four spokes, while the negative terminal is smooth.
Datasheet for the genuine LG HG2.
Dimensions and weight are hard to challenge here, since even the datasheets give these figures with fairly wide tolerances.
Internal resistance: the datasheet gives a typical value of 17 mΩ; the actual value is 14–16 mΩ. The battery I received measured almost 19 mΩ, clearly higher, which is another point in favor of it being counterfeit.
Another way to tell is by the shape and number of “spokes” on the positive terminal.
On the left is a Litokala battery supposedly sold as an HG2; its positive terminal has four spokes. On the right is the one I received, with three spokes.
The genuine LG HG2 has four spokes on its positive terminal. Litokala chose a battery for its version that looks more like the genuine one, although it isn’t genuine either. There’s no need to say much about the one under review: this third difference also shows that it’s counterfeit.
The fourth test is a capacity measurement. The genuine battery should be close to 3000 mAh. At a 1C current, I measured 2640 mAh; at 10 A, it was 2620 mAh—clearly less.
The fifth method is to check how much the battery heats up.
The load current is 10 A. The battery under review is on the left, and the Litokala copy is on the right. The result is identical: 74 degrees.
And now, the test results for a genuine LG HG2.
At a discharge current of 1C and a cutoff voltage of 2.5 V, its capacity was 2880 mAh, or more than 10 Wh (the counterfeit managed 9.3 Wh).
It also heats up noticeably less under a heavy load: 79 degrees, but at 15 A rather than 10 A. Unfortunately, I can’t properly test and compare genuine batteries right now, so I have to rely on results from older tests, which were far from perfect. Still, I think the difference is clear.
To sum up: -
1. Code — presumably counterfeit, possibly copied from batteries sold by FastTech.
2. Resistance — 19 mΩ instead of 14–17 mΩ.
3. Positive terminal — three spokes instead of four.
4. Capacity — 2640 mAh instead of 2880–3000 mAh.
5. Heating — 74 degrees at 10 A; the genuine battery reaches roughly the same temperature at 15 A.
Conclusion: 100% counterfeit.
Now for the Samsungs. My introduction to them began when one of the batteries turned out to be discharged to 1.3–1.4 V—a state you don’t see with genuine batteries, even after long-term storage. But I'll come back to this battery later.
My favorite INR18650-30Q cells all look pretty neat on the outside.
And here's the datasheet.
The positive terminal has three prongs, but they're rather large....
The dimensions and weight differ slightly from the cells I tested earlier, but that alone doesn't prove they're counterfeit.
The resistance is 20 mΩ; the datasheet gives a typical value of 13 +/-2 mΩ. The actual value was 12.9, so this is already a bad sign.
The positive terminal is different too. The original is on the left, the one under review is on the right. I think the difference is obvious.
The markings are a separate issue here.
There seems to be no visible difference; they're practically identical, with one small exception...
Samsung batteries have their production date printed either on the heat-shrink sleeve below the SDI abbreviation, or underneath the sleeve if that spot is blank.
Here, the heat-shrink sleeve is not only brighter and prettier, it also has no production-date marking. The original is below. If you look closely, you can see faint marking characters on the left that are missing from the one under review, which clearly indicates it's counterfeit.
In the 1C and 10 A tests, the battery delivered 2660 and 2700 mAh, respectively.
Comparing the results for the original (green and orange) with the one under review (red and blue), you can see that not only the capacity differs, but also the shape of the discharge curve. At the higher current, the counterfeit delivered slightly more capacity than at the lower current; with the original, it's exactly the opposite.
This is most likely due to the higher temperature during discharge, which in turn is caused by the higher internal resistance.
Counterfeit on the left, original on the right; discharge current is 10 A.
To sum up -
1. Code - no production-date marking
2. Resistance - 20 mΩ instead of 12-14
3. Positive terminal - larger contact area
4. Capacity - 2660 mAh instead of 2970-3000 mAh
5. Temperature rise - 76 degrees at 10 A; the original reaches 56 degrees at the same current.
Conclusion - 100% counterfeit.
The third battery is an ICR18650-26H. I haven't had one of these before, which makes figuring out whether it's counterfeit all the more interesting.
The production date is printed on the heat-shrink sleeve: TGQ1 with the SDIEM code. So I looked online for a date-code calculator, which gives a production date in early March 2016.
The datasheet for this battery series.
The positive terminal has five prongs and a fairly large central pad. The battery weighs 2 grams less than specified in the datasheet.
The resistance measured 48 mΩ, but it's hard to judge here because the datasheet specifies less than 100 mΩ, so technically it seems fine.
Since I hadn't come across these batteries before, I had to visit another site to find a photo of an original. It turns out the original should have six prongs on the positive terminal, not five, and the shape itself is quite different.
Interestingly, our online stores sell the same counterfeit with the same positive terminal as an original.
But what if I'm wrong and this is an original? Let's measure its capacity.
At 1C and 2C, I actually got 2486 and 2319 mAh, which is, in fact, consistent with the original, which should deliver at least 2340 and 2080 mAh.
And here I'll explain another aspect of testing. Someone once asked me why we need all these graphs when it's enough to simply measure capacity. The thing is, each type of battery has its own “signature”—characteristic “humps” and “dips”—and by comparing two graphs, you can tell with fairly high accuracy whether a battery is original or counterfeit. Of course, that only works if you have a discharge graph for an original battery to compare it with.
I took the discharge graph for an original Samsung 26H from the site mentioned above and compared it with my results.
First, the one under review, at discharge currents of 1C and 2C.
And the original.
Unfortunately, this person doesn't test using the standard C-rate sequence of 0.2C, 0.5C, 1C, 2C, etc., but instead uses 0.2 A, 0.5 A, 1.0 A, 2.0 A, etc. which, in my opinion, is wrong, but there it is.
Above, I chose colors that roughly match the colors of the graph for the original cell at 3.0 A and 5.0 A; in my test, these correspond to 2.6 and 5.2 A.
Two things stand out:
1. The original’s voltage drops much more sharply at the end of the discharge.
2. At 5 A, the original battery delivered more capacity than at 3 A; the one under review did the opposite.
3. In all the tests, capacity was above 2500 mAh. In my tests, both results were below 2500 mAh, and at 5.2 A it was only about 2300 mAh.
At a current of 5.2 A, the temperature reached almost 60 degrees.
Yes, this was a difficult case, but still:
1. Code — the date code is decoded correctly.
2. Resistance — within the datasheet specification.
3. Weight — 2 grams less than specified in the datasheet.
4. Positive terminal — five spokes instead of six on the original; the terminal itself is also shaped differently.
5. Capacity — 2319 mAh at a 2C discharge rate, instead of 2500–2550 mAh.
6. Discharge curve — less steep; at 2C, the cell under review delivers only 7.5 Wh, compared with 8.6 Wh for the original.
Conclusion — 100% counterfeit.
Now I’ve reached the battery that arrived almost completely discharged: the Samsung ICR18650-22P.
Its voltage was only 1.3–1.4 V, which should never happen with a normal (genuine) battery. Either it was stored who knows how, or it has a very high self-discharge current. My normal batteries can sit around for a couple of years and still retain their charge—not 100%, perhaps, but certainly not "dead flat".
First check: date of manufacture. The battery is marked 5ES2 with the code SDIEM, which corresponds to around mid-May 2014. If it’s genuine, then wow—it’s almost a collector’s item. This battery is 5 years old.
Datasheet for the original ICR18650-22P.
The positive terminal has three spokes and a small diameter. Its dimensions roughly match the datasheet, but its weight is 45.24 grams, which is above the datasheet’s maximum of 44.5 grams.
Resistance is 20 mΩ, which is actually pretty good—the datasheet specifies no more than 35 mΩ. But look at the voltage!
I put it on charge, and 1960 mAh went into the battery. I had to restart the charging process several times because at first the charger thought it was a nickel-based battery and stopped charging.
The resistance didn’t change, which once again shows that when measured correctly using AC, resistance is almost independent of the battery’s state of charge.
The shape of the positive terminal differs both from other Samsung batteries and from the original shown on this page of the test.
The key difference is the shape of the "spokes": on the original, they narrow near the "button"; on the one under review, they’re a little straighter. I’ve marked the area to look at in the photo. The difference is small, but it’s there.
Also, the diameter of the "button" is slightly larger than on my original cells, and its surface is rougher. But since these are different batteries, I can’t use them as a reference.
At discharge rates of 1C (2 A) and 10 A, I measured capacities of 1995 and 1857 mAh.
The discharge curve is very similar to that of the original battery. The only difference is that the original had a capacity of about 2050–2100 mAh in these same test conditions, rather than 1995 and 1857 mAh, and its capacity was the same at both discharge rates.
Energy capacity was 7.4 and 6.6 Wh; for the cell under review, it was 7.2 and 6.15 Wh, respectively.
There was also a test at 5 A, but unfortunately all that remains is the thermal image. In that test, the battery heated up to 61 degrees, so I decided to test it at 10 A instead (second photo), where the temperature rose to 77.5 degrees.
In my opinion, this was the most difficult test.
1. Code — the date code is decoded correctly.
2. Resistance — within the datasheet specification.
3. Weight — 0.75 grams above the datasheet maximum.
4. Positive terminal — very similar to the original, though with some minor differences.
5. Capacity — 1857 mAh at 10 A, instead of 2050–2100 mAh.
6. Discharge curve — very similar to the original.
Conclusion — very likely genuine. There are some minor differences, but if the battery really is 5 years old and was stored carelessly—as suggested by its 1.4 V voltage and high self-discharge current—the test results could well be as shown in this review.
The only things that point most strongly to it being different from the original are the slightly different shape of the positive terminal and its somewhat higher weight. But in any case, I wouldn't buy these batteries, precisely because there's no way to know how they've been stored all this time.
A few comparison photos.
My original batteries are on top, the ones under review are below.
The original 30Q is on top, the ones under review are below. The difference in the color of the pink heat-shrink tubing is especially noticeable: the clones have a more saturated color.
You can also compare the shape and appearance of the crimping around the positive terminal, but for an accurate comparison it's sometimes best to have an original in hand, since photos don't always show the details.
Positive terminals: originals on top—30Q, 35E, 20S; the ones under review below—30Q, 26H, 22P.
And this is a bonus track: another INR18650-30Q, a couple of which came my way earlier.
These batteries are textbook examples of a “typical fake,” and the heat-shrink tubing has even started peeling off one of them.
The two batteries have completely identical markings, but different positive terminals!
By the way, about the markings: they should be under the heat-shrink tubing. On the pair of originals (left), you can just about make them out, while the ones on the right have none. The key point is that the heat-shrink tubing has no date code. If you see a battery missing one of the codes, it's 100% fake.
Two original 30Qs on the left, two fakes on the right. No further comment needed...
Even so, one battery had an internal resistance of 18.6 mΩ, about the same as the first 30Q I showed above. The second was nearly 33 mΩ, with a voltage of just 1.8 V.
Despite all that, capacity was only 2650–2700 mAh, but it barely changed at discharge currents of 3, 6, and 10 A—and actually increased as the current went up.
Battery temperature at discharge currents of 6 and 10 A. The original reaches 56 degrees at 10 A, compared with 74 here.
All in all, it's a fairly decent clone, with a maximum current of 10 A and slightly lower capacity. They strongly reminded me of the difference between original LG HG2 batteries and their clones—the results are much the same.
But what really shocked me was the second battery in the pair. This is what it looks like after sitting around at a friend's place for about 8–10 months. I tried charging it; it seemed to be charging, but then I thought, why bother? I just removed the heat-shrink tubing, because this thing can't be used—it has to be recycled.
And here's my friend, who sells batteries, taking apart a fake “battery” from a power bank bought on AliExpress. As they say, it's both funny and tragic...
So, what can we conclude?
Popular battery models are the most frequently counterfeited. In this case, that's the “chocolate bars”—LG HG2 and Samsung 30Q. The ICR18650-26H shown here also clearly looks fake, but the ICR18650-22P is less clear-cut. If you overlook the slightly different terminal shape and weight, you could say it behaved like a genuine battery that had spent five years forgotten in some far corner of an unheated, uncooled warehouse. Besides, it's not a very common battery, so it's less likely to be counterfeited.
If you've bought batteries and aren't sure they're genuine, you can usually check a few things:
1. Whether they match the datasheet—for example, battery weight, capacity, and internal resistance.
2. If you have several batteries, their internal resistance should be almost identical. Clones usually vary from one unit to another.
3. The shape of the positive terminal. Clones often look very different.
4. The discharge curve should match the original—literally “one-to-one.”
5. The markings, especially the date code. Some manufacturers (SonyMurata) use a unique code for each battery, while LG uses one for the whole batch, and even then the odds of buying two with the same code are actually pretty low.
6. If everything looks right but you're still unsure, ask someone who can help, at least in the comments under this article.
7. If you bought the batteries on AliExpress, there's a 99% chance they're fake. You can buy them on Taobao; they have some fairly decent Chinese-made batteries without famous brand labels. At least that's not a scam where they can pass off anything as Samsung.
That's all from me. I hope this was useful, and as always, feel free to ask questions.
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This model is included in the summary table: Battery comparison: measured capacity and resistance
The figures from this review are in the measurement database: Batteries
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