While the Vantec Power Gem looks like just another portable battery for charging your cell phone, it has two great properties that are unique. It allows you to recharge the battery while using your device and delivers uninterrupted power to the device when you yank out the power cord.
I have used this for about a month on my main Christmas light Z-wave Pi and have prevented a few accidental shutdowns while moving around my office in preparation for Christmas. It has no problem supplying the power needed for the USB Z-stick. Many Pi users (including myself) have experienced, corrupted SD cards due to power failures.
As a true UPS / Battery backup, it is missing a few things (like surge protection). But if you are looking for something cheap to keep your Pi running in the event of an outage this will work.
One con -the Vantect Poser Gem 3500mAh, doesn’t last as long as other portable batteries in the same power storage / output range.
New Egg - Add the coupon code: EMCWVWN245 and the cost should be $9.99