USB battery box XY-8027

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A thin usb power bank with a build in small flashlight and usb charge cable.
The official specifications are:


How does it look

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I got it in a cardboard box without any markings on it.

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The contents was the power bank and a cable for charging the box or a phone from the box.

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The box not very thick.

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It has two usb connector, one for power input (i.e. charging the box) and one for power output (i.e. charging a phone). There is also a white led that can be used as a flashlight, it is turned on and off with a double click on the button.

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In addition to the usb output, the box does also have a short cable with a micro usb connector on it. The cable is very thin and probably has to be handled careful.

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The control panel, it has one button to reactivate the output (Usual it turns on automatic) and see charge status. It can also be used to turn on/off the flashlight with a double click.
There is four leds hidden beneath the black strip. They are used to show charge state and function (charge or usb output).

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The box contains a circuit board and a lithium polymer battery.

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The battery is specified as 4000mAh.

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The four indication leds can be seen on this side of the circuit board.

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This box is built with microcontroller, a boost converter chip and some transistors to disconnect the battery.
It looks like the isolation on the wire to the micro usb connector is damage.

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Measurements


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The load sweep on the two connectors looks nearly identical. There is higher resistance in the micro usb cable, giving slightly lower output voltage, when load increases.
The box can deliver 1.4A and then it turns off.

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Running at load at about 0.5A looks very good. The output turns completely off when the battery is empty. The box can deliver about 2800mAh.

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Increasing the load to about 1.2A does also look good.

10ohm

There is a lot of noise at 0.5A with 22mV rms and 143mVpp.

4ohm

Increasing the current to 1.2A, increases the noise: 57mV rms and 371mVpp.

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Charging is not exactly a CC/CV profile, but the result looks acceptable. The battery is about 4100mAh.
This charging profile is slower than CC/CV, it takes about 6 hours to charge the box and it requires a 1A charger.



Conclusion

This power bank has enough capacity to charge most phones and can also supply a decent amount of current, the small flashlight makes it possible to connect the cables, even if it is dark. The build in cable is a nice feature.
Using lithium polymer battery gives power bank this is a very nice size.



Notes

The usb box was supplied by USBANDCO for review.

Read more about how I test USB power supplies and chargers