Chinese battery developer Mipow has released updated versions of two battery packs we covered last year. The first is Power Tube 5500 ($99), a revised take on the 3000 and 4000mAh capacity battery packs we reviewed last fall, again using an extruded rectangular shape despite the "tube" name. We liked that the original had a cap that popped off to reveal an integrated Dock Connector plug; unfortunately, this one drops that plug in favor of a bunch…
