The iPhone 4/4S has a decent 1440 mAh battery, but sometimes that is not enough. Fortunately, there are quite a few battery cases available for the iPhone that stretch the time between charges. A new case from Spyder Digital Research adds a full 2000 mAh battery to the iPhone, along with a dock to make charging as easy as popping the phone into the dock.
Both the case and the dock are solidly constructed as well as any case for the iPhone. The polycarbonate case has a rubberized finish that makes holding the iPhone in the case very secure with no concern about dropping it.
The iPhone fits snugly in the case by sliding it into the main part and sliding the top cowl into place. It protects everything on the iPhone except the front. It adds 2.6 ounces to the weight of the iPhone, but it feels solid in the hand rather than too heavy, although some may find it adds too much weight.
The PowerShadow is designed to be used in two manners: as a constant case for the iPhone or only when extra battery life is needed. In the latter, the case is charged with the included microUSB cable by plugging it into a USB power source. The cable plugs into the microUSB port on the bottom of the case next to the dock connector. The case alone can then be tossed into the bag for hitting the road, just in case it is needed.
The case from Spyder shines as an everyday case for the iPhone if you don't mind the extra bulk. The battery in the case is bigger than the iPhone battery, so it more than doubles the time away from the charger. I can easily go two or three days of heavy use with this case.
Charging it is as simple as dropping the iPhone and case into the included dock. It is designed to automatically line up the connector on the case bottom with the contacts in the dock. The iPhone and dock stand up in the dock securely.
The case is used like other battery cases for the iPhone. When the case is turned off the iPhone works normally and uses the phone battery. When it drops precipitously low, the PowerShadow i4 case is turned on by pressing the on/off button on the back for 3 seconds. This runs the phone and charges the iPhone battery simultaneously.
There are four blue LED indicators above the case power button which indicate the charge level of the battery in the case when powered on. The case battery is turned off by pressing the power button for three seconds again, which switches back over to the iPhone battery.
The PowerShadow i4 battery case doubles the thickness of the iPhone, but is worth the bulk given the large battery. The unique dock turns it into a convenient method for more than doubling the battery life of the iPhone 4/4S. It is $89.99 from Spyder which is not the cheapest option available, but the dock is unique among offerings. It is only available in black, but it looks pretty good with my white iPhone.