LG INR18650-M36 batteries claim a record-breaking 3600 mAh—is it true?

Yes, friends, judging by the claimed capacity, these could be considered record-breakers in the 18650 form factor. 3600 mAh, no less! But is that what you actually get? A review, tests, conclusions—as usual.


One of the reasons I bought a couple of these batteries for testing and 19 for a friend was their high claimed capacity at a fairly affordable price. When I ordered them, they cost €2.95 each, or about $3.25, which seemed like a good price for the claimed specs.

By the way, the photo of this very package, with the M36 batteries, is the one you saw at the very beginning of the HG2 review.


They look like the MJ1 batteries I showed earlier, except the heat-shrink wrap is blue rather than green.


They’re listed for use in electric vehicles, most likely because of their good capacity-to-size ratio. Curiously, though, the datasheet doesn’t mention capacity in Ah anywhere—only in Wh.
The rated capacity is listed as 12.5 Wh, which at a nominal voltage of 3.63 V works out to 3440 mAh. I don’t know where the 3600 figure came from. Also, the datasheet doesn’t specify a 1C discharge current, for example, but instead gives 1.5C (5 A), which works out to 5000/1.5 = 3333 mAh—not 3600.


Anyway, the tests will give us more to think about, so let’s get on with the review.
Nothing unusual on the outside: the familiar 18650 form factor. According to the R191 marking, the production date is 2018, day 191 of the year—in other words, mid-July.


Dimensions and weight.


The datasheet also shows the appearance and shape of the positive and negative terminals, and they match the photos above.


A conditioning cycle with a capacity measurement gives about 3600 mAh, but in this case the charger overstates the result. Still, it looks pretty good.


Now for the results from the ZKE EBC-A10H electronic load. Things are a little... more modest here: 3456 mAh at 0.2C. That’s quite a lot, but unfortunately it’s not 3600.

The datasheet specifies a maximum discharge current of 5 A. I tested it at up to 8 A, and the battery delivered 3330 mAh—only a little less than at the specified 5 A, which is pretty good.


Temperature at 5 A and 8 A. The battery didn’t get very hot, which is why I went ahead and tested it at 8 A.


The nkon website also lists a maximum discharge current of 5 A for these batteries. I assume that’s simply based on the datasheet, but many online stores here—including the Kharkiv-based batterex—claim a maximum current of 10 A.


Since the battery performed well at a discharge current of 8 A, I decided to raise the bar a little and test it at 10 A. Few high-capacity batteries are rated for that kind of current: the Panasonic 3400 mAh is rated for 2C (6.8 A), the Samsung 35E for up to 8 A, and I think only the LG MJ1 is rated for 10 A.

But everything went fine: at 10 A, the battery delivered 3329 mAh. The first sample delivered 3330 mAh at 8 A.


It did get hotter, of course, which affected the energy delivered in Wh: 11.17 Wh at 8 A, and 10.96 Wh at 10 A.
Temperature at 5 A and 10 A.


I’ll venture a guess that the manufacturer simply played it safe by specifying a 5 A discharge current. The internal resistance of 23.5–24 mΩ is another indirect clue. The MJ1, which is rated for 10 A, has an internal resistance of 27.7 mΩ, while the Samsung 35E, rated for a maximum of 8 A, has an internal resistance of 20 mΩ.


And of course, here’s a comparison with other high-capacity batteries: the LG MJ1 and Samsung 35E. The M36 comes in between the two competitors mentioned above, behind the LG MJ1. In my view, its specs are very similar to those of the Samsung 35E.


Now for the conclusions.
The tests showed that this is a decent battery. It can handle load currents of up to 10 A continuously without any trouble, and it has good capacity. But unfortunately, it doesn’t deliver the claimed 3600 mAh. In the tests, the MJ1 made by the same company clearly outperformed it, though the MJ1 costs a little more.
The battery reviewed here is very similar to the Samsung 35E, but a little better—though the 35E costs less. When you factor in the price, they basically come out even.

That’s all for today. I hope you found this useful.