Amazing and cute emergency external power back-up for Android phone is now emerging in the market and it is the Mili
Power Bean HB-M20 which is the answer for power shortage for android-powered mobile phones,
How much voltage could it hold?
Adorable External Power Source For Android Phones
It sure is adorable I tell you, but it still packs a punch to say the least. This Power Bean from Mili has a voltage input of 5V, which is enough to charge your gadgets like smart phones and tablets, specifically Android-powered ones. It uses a microUSB output, so phones with this kind of port (Android phones mostly) can be charged with ease. Since it uses the microUSB, it uses the most recent technology, the USB 3.0. It does what it is intended to do, to charge your gadgets with microUSB. To fully charge this Power Bean, you need to plug it in a normal USB port using the other end of the cable and wait for it to be fully charged, around 5 hours.
The only downside though is anesthetically it is a fingerprint monster. Expect to wipe it more often than normal because of its glossy exterior which is prone to fingerprints. It also comes with a variety of colors though, but the default black and blue color scheme is a pretty good winner to me.
The Power Bean HB-M20 in an alternative color.