View source for DX XIAOMI Genuine 10400mAh Power Bank

This looks like a good find; 
[http://dx.com/p/311565?Utm_rid=65939668&Utm_source=affiliate http://dx.com/p/311565?Utm_rid=65939668&Utm_source=affiliate]

EDIT: This product arrived with me after waiting for over a month, what a disappointment.

This is an excellent power bank, all of the reviews rave about the quality of the case, the clean design and the quality of the cells and circuitry inside. I don't disagree, it's well built, solid, gives good charge output.

However, you *can not* use this as a UPS as mentioned in other reviews. When power is lost on the input, the output power also drops for a second. This makes it useless as a UPS. I've seen people expecting to use this with a Raspberry Pi as a cheap UPS solution, this just would not work as when the power is lost on the input it'll be lost on the output.

This is also not useful as a solar battery when hooked up to a solar panel, if the charge current drops below that which the charging device requires the power is lost until the current becomes high enough to sustain the output. This makes its use limited.

If you take a voltmeter and look at the output voltage, it changes to that of the input voltage when the input is connected. It actually looks to be connecting the input direct to the output, it's not feeding your device direct from the internal battery.

If your input voltage/current is not sufficient to charge your device, then there is no output on the device being charged. Again, this makes it useless to use with a solar panel to try to 'smooth out' losses in solar (sun behind a cloud etc).

Aside from these issues, the device gives a good output current and can easily charge an iPad/iPhone etc.