18650 3400 mAh batteries

Today, I have a very brief overview, even more likely a “photohall” about buying another batch of lithium batteries.
Inspection, tests, conclusions.
These batteries on the product page are declared as “original”, but since I cannot fully reliably either prove this or disprove it, I will take them as copies.

But in my opinion more information will give the tests.
And so, it was ordered 4 lots of 6 pieces each, 12 went to a comrade and 12 came to me. Packed as always neatly, a cardboard box plus the batteries themselves were in soft packs of 6 pieces.

They look neat, only here the black part of the heat shrinkage is kind of worn, I don’t remember the original ones to have that.

The marking is clear, but along the entire length of the heat shrinkthere is a noticeable seam, again, most likely the heat shrinkage is non-native, but I will not say 100%. The release date is marked as 8103, for the original it would mean January 3, 2018. Some time ago I showed these batteries, there was a date January 30, 2017, so even if the heat shrinkage is non-native, the date is still updated
The weight of the batteries was basically about the same, but one lighter was found and the pair were noticeably heavier, I used such a “imbalance” pair plus two normal ones further in the tests.
Length, diameter, everything is normal.

The positive contact is flat, partially closed by an insulator, because in some devices there may be no contact. There is no protection card, because in devices where there is no protection against overdischarge, it is better not to use it.

The first test is a conventional charger, although it measures the capacity in the correct way, i.e. when discharging, I still use it only for an approximate assessment.
Batteries had about 50% of the charge, while discharging showed a rather large run-up. The first is the lightest battery, the second is the heaviest, the third and fourth are taken somewhere from the middle.

For further tests, we take a more accurate measuring device, an electronic load that combines the battery tester.

I decided to carry out tests with the first and second batteries and to begin with, we will measure the actual capacity declared on the product page was 3400 mAh.
Capacity is usually measured at a current of 0.2 ° C, in this case I set 3400/5 = 680mA.
Capacity as usual was measured at three voltage levels, from full charge to 3 Volts, then from 3 to 2.8 Volts, and then from 2.8 to 2.5, the final result summarized.
Battery number 1.
The total capacity is 3125 + 129 + 90 = 3344 mAh, nearby, butIt does not reach a little, although with a charge current of 680 mA, it was necessary to stop it at the level of 68 mA, but my minimum was 100 mA, so an undercharging is possible.
Capacity to Wh has made 12.077

Second battery
The total capacity is 3130 + 144 + 90 = 3364, almost near. Bt it turned out 12.131

Well, then I decided to test the same batteries at a current of 1C and 2C (maximum for them).
The first battery, the discharge current of 3400 mA (1C).
Capacity in mAh was 2897 + 191 + 156 = 3244, quite well, although the new branded gave a little more. In Whit out 11.094.

The second battery, current 6.8 Ampere (2C).
The capacity in mAh is 2486 + 416 + 319 = 3221, or 10.386 Wh.

Along the way, at the very end of the discharge by currents 1C and 2Cthe temperature of the batteries was measured, it was 43.5 and 69.7 degrees, respectively, the original had a little lower, literally a few degrees, but the discharge current there was 3200 and 6400 mA.

After all the experiments, the internal resistance was measured, although of course the first couple had to be measured before the test, but I will not repeat the experiments, this is too long a process.
On average, it turns out about 33-34 mW, for those batteries that I tested in the summer (also Litokal) was about 30-32 mW, I think that this difference can be neglected.

In short, I can say that for all sorts ofdevices that do not need large currents, but need the maximum capacity, these batteries fit perfectly. The same devices are included in the list of suitable devices, all the more so because there the capacity spread is not critical. Alternatively, it can be used in laptop batteries, but it is better to select them by capacity before use.
I have everything on it, I hope that the review was useful.