Last year, Kensington released the Mini Battery Pack and Charger for iPhone and iPod, a $50 package with three parts: a metal and plastic battery attachment, a plastic cap, and a retractable USB cable. When recharged to its peak, the battery added roughly 50% of a full charge to an iPhone, or an iPod recharge that ranged from complete to nearly complete depending on the model. Now Kensington has repackaged the battery in a new and more expensive set called the Charging Dock With Mini Battery Pack for iPhone and iPod ($70).

First things first: apart from including a gray cap rather than a clear one, the battery has the same general pros and cons as its predecessor, using the same shape that basically matches the flat front and tapered sides of the original iPhone and iPod touch, filling the Dock Connector port, blocking the bottom-mounted headphone ports of iPod touch and nano models, and partially obscuring the bottom microphones and speakers of various iPhones.
For the nano and touch, then, it’s only usable as a passive recharging accessory rather than as something that can fuel a device that’s currently in use; for most features, iPhones and iPod classics can be used simultaneously with the battery.
Notably, the Mini Battery Pack took a mostly discharged but turned on iPhone 3GS using a precise percentage-based battery meter from 12% power to 71% power, restoring 59% of its charge; other models will vary based on their different batteries and power consumption characteristics.
What’s new here is the method by which the battery is charged. Kensington replaces the USB cable with a simple gray rubber and white plastic dock that lets you charge both the battery and an iPhone or iPod at the same time. To be clear, this isn’t an audio or video dock: the dock has a USB port on back, nothing else, and a Universal Dock well in front. Kensington supplies an iPhone 3G or 3GS Dock Adapter, a USB cable, and a wall adapter; you supply Universal Dock Adapters for any device save for the iPhone 3G/3GS.
There was only one small surprise in connectivity.
When the dock was connected to the wall adapter, we plugged an iPhone and the battery in at once, and they sat together and charged. But when we connected the dock to a computer via USB, the iPhone took priority for charging and synchronization, cutting power off from the battery; however, it did create a stable connection for iPhone syncing and charging, enabling us to do a software upgrade to the connected device without any issue. On disconnection of the iPhone, the battery began to charge again. In other words, you have the choice between computer and wall charging, but if you want to reliably charge both pieces at the same time, stick to wall power.
Is the Charging Dock With Mini Battery Pack as worthy of its asking price as its predecessor? We were a little bit on the fence, but ultimately felt that the answer was yes.