Raise your hand if your iPhone 4 has ever flashed the 20-percent-left battery warning at a most inopportune time, with no usable or practical outlets in sight.
Yep, me, too. I've been the girl scanning cafe walls, poking at ambiguous hinged metal floor plates, and scouring airline gates in the hopes of finding a power source more times than I'd like to admit. If that's you, too, you should consider investing in a charging case that's equipped with its own battery pack.
Over the last few weeks, I slipped CNET's iPhone 4 into both the Mophie Juice Pack Air for iPhone 4 and the Dexim Supercharged Leather Power Case, competitors that each promises to resuscitate a flat-lining iPhone 4 at least one additional charge, and help protect it from dings and dents while it's at it. (Butterfingers over here appreciates that trait as well.)
Mophie Juice Pack Air
Mophie Juice Pack Air ($79.95) was first up on the chopping block. Like other Mophie Juice Back cases, it's got a sturdy two-part body made from matte plastic with soft-touch properties. The Juice Pack has grooved internal edges, so that the iPhone slides snugly into the bottom portion and over the charging pins. You then slide the upper portion over the top of the iPhone; both pieces dovetail together.
The Mophie case completely covers the iPhone, leaving holes for the camera, headset jack, volume controls, and so on. In addition, there's a Micro-USB charging port from which you can power up the Juice Pack on its own, or while it charges the iPhone. There's also a charging switch that powers the electric flow between the case and the iPhone. Best by far is the power indicator, a button that shows in LED lights how much power is left in the case. It works the same when you charge the case up.
Although it weighs only 2.3 ounces, the Mophie Juice Pack Air adds notable weight and bulk to the iPhone that elicited a fair amount of teasing. However, it did supply one full charge as promised.
Dexim Supercharged Leather Power Case for iPhone 4
For its part, the Dexim Supercharged Leather Power Case for iPhone 4 ($79.90) also offers protection and an extra charge, though with its leather exterior, the case is geared more toward business professionals. Unfortunately, Dexim's case looks cheaply made. There's the holster part where the phone slides in, but it never looks like it fits tightly even after the charging pins connect. A cutout on this back portion lets you shoot photos without removing the case.
Then there's a leather flap that flops down in front when the case is open, much like a sandwich board hinged the wrong way. At the top of the second flap is a hook closure that wraps around the top of the iPhone. It secured fine during my use, but I wasn't sold on it as a premium product. It's a bit heavier, too, at 3.8 ounces, and much bulkier than the Mophie case.
Externally, the Dexim case has a Micro-USB charging port just like the Mophie case, and a power switch to charge the iPhone from the case. Like its competitor, the Dexim Supercharged Leather Power Case supplied a full charge after the iPhone ran out of steam. However, it lacks Mophie's useful indicator for determining how much charge is left in the holster.
Winner: Mophie Juice Pack Air
You may bypass both of these options for charging cases, but for our money, we'd pick the Mophie Juice Pack Air. It may add weight and heft to the otherwise slim profile of your iPhone 4, but its handy power indicators and snug fit make it a better-constructed product.
Do you have a different favorite charging case? Share it in the comments.