Extra battery power has always been a concern for iPhone users, and many accessories now offer to keep Apple’s handsets charged. Some of the more common options these days are cases with integrated batteries. As they are being engineered to higher degrees of quality, manufacturers are beginning to look for ways to set their products apart in ways other than just battery capacity. XPAL/PowerSkin’s PowerSkin ($60*) and Scosche’s SwitchBack Surge ($80) for iPhone 4 are just that, each with a feature or two that’s rare among competitors.
Unlike most battery packs, PowerSkin isn’t a two-piece slider-style case. Instead, it’s one unit with a hard plastic back and pliable silicone rubber edges along the left, right, and top. Those edges have enough give that inserting and removing the iPhone 4 is very easy. One of the benefits of the rubber case is that you’ll actually have button coverage: the Sleep/Wake button and volume buttons are both protected, but still work just as easily as if they were not. Openings for the headphone port, mic, and rear camera are all appropriately-sized, and the there is enough clearance for the side switch that GSM and CDMA iPhone 4s fit without a problem. There are cutouts for the microphone and speaker on the bottom of the case, both of which continue to work just fine.
At the bottom right corner of PowerSkin, there’s a Micro USB port for charging both the case and the iPhone 4 itself. On the bottom are four indicator lights and a combination battery check/power button.
To turn the case on or off, you hold the button for two seconds. While this is printed in the included manual and on the packaging, it’s not as intuitive as a dedicated button would be, and on at least one occasion we didn’t know whether a substantially discharged unit was turned off or dead.
As an offset to the relatively low price and protection, PowerSkin certainly adds some bulk to the otherwise slim handset. It more than doubles the thickness, from 0.37” to 0.77”, and also adds about half an inch to the height. More than 50% is added to the weight of the unit as well, rising to 7.68 ounces—almost half a pound.
PowerSkin has a 2000mAh battery, and the company claims it will double the life of the phone. In our testing—with a powered-on 3G/Wi-Fi-connected iPhone 4 with the screen turned off, no calls coming in, and no audio playing—this was close to but not quite true. In just under an hour and a half, the battery charged a fully depleted iPhone 4 to 88%. We repeated the test and the result was the same. Some energy is lost in the transfer between the two devices, explaining why this cell doesn’t fully replenish the 1420mAh power source in the iPhone 4. This is not a bad result, especially when considering the price of the case, but it’s not as impressive as one might gather from the marketing.
SwitchBack Surge is also unique, using a twist on the standard slider-style case. This accessory is composed of hard glossy black plastic. On the back is a interchangeable plate—black and metallic silver options are packed in—that serves as a sort of shield.
Underneath is a button that releases the top slider portion of the case. The iPhone 4 slides right into place. All of the appropriate openings are there, although unlike PowerSkin there is no button coverage. Oval-shaped openings along the front “chin” allow access to the microphone and speaker.
In addition to the four radiating battery indicator lights and a button to check the status on the rear of the case, the bottom has a Micro USB port and a power switch. Unique to SwitchBack Surge is the fold-out stand on the back. It sits flat while not in use, and works in a pretty wide range of landscape orientation angles. While the stand feels kind of flimsy, it does hold the iPhone up well, and we appreciated the extra feature—especially since it doesn’t add significant bulk.
The dimensions of the case are very similar to those of PowerSkin. It’s just as thick, although a little bit wider and a hair shorter. SwitchBack Surge also feels a bit lighter. Performance from the 1800mAh battery was just about what Scosche claims: in a little over an hour, the iPhone 4 we were testing took a 75% charge before the case’s battery was depleted. The company claims that the cell will bring the iPhone 4 up to 80%, so it was quite close.
