Power Cartel: EasyAcc U-Bright 3,000mAh USB Power Bank Teardown

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This time, let’s have a look at what’s EasyAcc U-Bright 3,000mAh USB Power Bank inside.

What feature determines a power bank? Most answers come to the battery cell.

As the specifications shown, it provides 2 amps of current through USB and charge at 1 amp, compared to 1 amp current and 1 amp charge.

Upon a USB breakout board which allows me to do more precise tests, and I’m impressed that the EasyAcc indeed comes to its specs. When fully charged, it can deliver ~1.9 amps of current at ~4.8 voltage, within the specs for USB for a sustained period. It does as good a job of maintaining voltage with a ~2A drain as the Anker does with a ~1A drain, in fact, it does about as well with its single cell as some 4-5 cell power banks I have. When discharged fully, it recharges at ~1A.

While opening the outer case, here come a pink 18650 Li-ion cell and a couple of PCBs.

IMG_6890-e1418936246632-1024x585As the pic shows, the pink is printed with letters, LGABD11865 (extensive tests on lygte-info.dk). Compared to other cells of similar capacity, this cell seems to be an excellent choice for this application, maintaining a higher voltage than most competitors at the 3-4 amps required to get 2 amps 5 voltage out of the boost converter.

The cell is soldered to one of the PCBs.  On one side, there are the four LEDs to indicate the operational status of the deviIMG_6896-1024x768ce and charge level of the cell. There is also a momentary switch, to turn the USB output  and the flashlight on and off, wires to the flashlight LED, and two identical 8-lead chips marked “8205”. At the center of the board, there is an 6-lead IC, labeled with a logo, and “301B, G60Z”.

On the opposite side, there is the microusb connector for power input, a 14-pin IC with the markings sanded off. This is a microcontroller. A second IC has 8 leads and is labeled with a logo, and “4057D,  1339”, which is a ME4057D lithium ion battery charging IC from Nanjing MicroOne Electronics. The ME4057 series is a linear charger and can charge at up to 1A, and the D version has a 4.35v charge termination voltage.

The board itself is labeled DBK-C0029-B-v2.2, 2013-9-4IMG_6900-e1418973271148-1024x788

The second PCB is stacked on top of a 6-pin header on the first PCB. It is notched to hold the USB host connector. On one side there is the the 6-pin socket that mates with the header on the other board, and a shielded inductor.

On the opposite side while probing around in some sloppily applied potting compound and found an IC in a square package, the reviewer couldn’t make out any markings, or even quite how it was attached to the board, guessing that it is a boost-converter IC. Remaining under the potting compound is a large surface mount diode.

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