BAK H18650CC 2150mAh Batteries

I've been asked about testing BAK batteries many times, and I've even tested one of this company's products. Recently, though, circumstances brought a few more batteries my way. One of them was another BAK, which naturally caught my interest.

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I got four cells. I randomly picked two for testing; I may check the other two later using a simplified method.


I couldn't find a proper datasheet, but I did find a website with the specifications and a file listing the main parameters, which I used as the basis for my tests.


The positive terminal is flat, the markings are very basic, and the overall appearance is quite plain.


Dimensions and weight. As you can see, the diameter is slightly over 18 mm, at around 18.4–18.5 mm.


Since I don't currently have a multi-channel charger, which I used for the "conditioning" cycle, I had to run it using the same EBC-A20/

I didn't fuss over the test settings: charge and discharge at 1 A, with discharge down to 2.75 V as specified in the datasheet.

The first cell was initially charged to a little over half capacity.


The second cell showed a similar result.


There are two charging modes: normal, at 0.5C, and fast, at 1C.
In normal mode, charging took 2 hours and 15 minutes. The CV phase was short, which is good to see.


The fast-charge results also look very good to me, but to extend the battery's service life, I wouldn't recommend this mode. I'd limit the current to 1.5 A instead.


I ran 7 tests: charging at 0.5C to 4.2 V, with cutoff when the current dropped to 0.1 A, then discharging to 2.75 V. Discharge currents were 0.2, 0.5, 1, 2, 3, 4, and 5C.

The battery delivered its rated capacity without any trouble not only at 0.2C, but also at 0.5C, which is an excellent result. It performed well at the other rates too, but I wouldn't load it above 3–4C, since the voltage sag was already noticeable at 5C.


Temperatures at 3, 4, and 5C were also no cause for concern.


The second cell produced almost identical results.


The second cell ran a little cooler, though I think the ambient temperature was a factor.


I checked how closely the cells matched at 0.2, 2, and 5C, and the results were excellent here too. A noticeable difference appeared only at 5C, which I wouldn't recommend.


Battery impedance before testing, after "conditioning," and after all the tests.


These batteries don't have any standout specifications: capacity is just 2150 mAh, and the current is limited to 10.75 A. However, their parameters match very well, they run cool, and they're not very expensive. That makes them a good choice for a range of applications—the choice is yours.

That's all for today. I hope you found this useful. Hang in there, friends; I'm sure everything will be fine.