Ultra protective iPhone cases have long been excluded from packing in a battery pack. Probably something to do with too much bulk to make it viable. Not anymore.
Word arrived today that Otterbox will start to sell their Defender Series Ion Case on April 18th for $129.95. Not exactly a drop in the bucket compared to other cases, but since you get significant drop protection as well as a back up battery that measures 1,450mAh, it’s a reasonable caveat. A screen shield is also built-in to the case, and while it doesn’t appear to make the phone impervious to liquids, it should mitigate your risk if you tend to spill or take runs in the rain.
Unfortunately, the Defender Series Ion Case is only compatible with the iPhone 4 and 4s. And while the company promises double the battery life, it’s likely you’ll get about an 80% recharge depending on usage, though they’re including an app that is said to optimize the battery process.