Good size, good weight and a lot of power, all in a pack that can charge almost any device.
An unfortunate shiny surface makes the battery look battered and bruised easily, but does not affect the overall usability of the battery.
While the physical device may, unfortunately, be prone to scrapes and scuffs, this battery is certainly one to consider if you travel a lot, spend a lot of time at conventions, or just have a lot of devices that you use frequently.
Our testing was twofold for this product. We ran both our official battery test, as well as a practical test. The battery is 10 amps, which means it should be able to charge an equivalent amount of battery power in other devices.
With the JB-30-10000 in tow, we headed to an all-day developer event. Obviously, at an event like this, power is at a premium. There are often not enough outlets for everything that needs to be plugged in, so devices run on battery all day long. Devices like MiFis tend to not last long, so an alternate power source is imperative. During the day, we charged 3 different phones and a MiFi. By the end of the day, the battery pack was still showing 4 out of 4 battery indicators.
Using out Lumia test device, we ran our in-house battery test, with the addition of the external battery attached. On our normal test, the Lumia 620 runs around 10 hours and 15 minutes on a full charge. Using the full battery, plus the JB-30-10000, we averaged a little over 75 hours. Based on the 10 amp power pack and the 1.3 amps in the Lumia's battery, the overall charge should have lasted 7.7 times its normal length, in a perfect world. That would have the charge last around 79 hours, but with power loss through charge technology, this is a nearly perfect charge transfer.
The overall build quality is sound. The box is sturdy and is capable of taking a decent amount of abuse. Unfortunately, the finish is entirely glossy, which means that it is fairly easy to scratch. It also means that fingerprints show and stick around for a while. The power button is small and fairly flat the body, making finding it without looking difficult, but it does provide some protection from accidental shut-off while in a bag. The USB ports are a little tight, which makes removing the USB plug difficult, but it also prevents accidental unplugging.
10 amps is a lot of power to pack into a small box, but this device manages to do it fairly well. While its weight is a little more than you might expect, it isn't unmanageable. It also isn't in the top half of the heaviest 10 amp power packs we have tested. In fact, it does come in under the weight of some of our older, smaller power packs. The physical size is about what you would expect. A little smaller than many 10 amp packs, which certainly makes portability a lot easier.
There are 2 USB ports: 1 amp and 2.1 amp. With these options, you can charge almost any device, from a wide array of phones to many tablets, e-readers and even gaming systems. It will, of course, not charge devices not capable of charging on USB, such as Microsoft's Surface. The pack can also be charged on USB, creating a perfect circle. The micro-USB port means you can use just about any charger you have around for any of your devices, so long as you don't have an Apple device.