Some of the accessories we test are solutions in search of a problem, but Mophie’s Juice Pack for iPhone ($100) is the exact opposite: thanks to a rechargeable Lithium-Ion battery stored inside of its iPhone-only docking shell, it literally has the power to remedy one of the iPhone’s best-known issues — limited battery life.
Let’s start with the positives. The Juice Pack isn’t the iPhone’s first battery option—APC was one of the first to market a battery, the UPB10 (iLounge rating: B), as iPhone-friendly—but it’s definitely the first that is designed specifically to be used all the time with the iPhone. Mophie has created a holster-like black plastic shell that wraps around the iPhone’s sides, bottom, and back, with a male Dock Connector sticking up and a female Dock Connector facing down from its bottom.
The soft touch rubber shell doesn’t come all the way up the iPhone’s back, but overlaps enough of the camera to have a half-circle cut out to avoid interference. It includes gray side grips for easy carrying, and in what can only be described as the designer’s fancy, has an all-green interior. With the iPhone inside, only a little of the green peeks out: two cut-outs next to the Dock Connector provide room for the bottom speaker and microphone to breathe, and be used. Callers reported that we sounded pretty much the same with or without Juice Pack on—a good sign that Mophie avoided a big potential iPhone usage problem.
Juice Pack’s battery performance also lived up to Mophie’s claims.
Four blue LED lights on its back—not five, as claimed on the packaging—let you know how much of the charge remains, if you press a small black button to their right. When they’re all full, the company promises that Juice Pack will double the iPhone’s advertised battery life, giving it the ability to run for 8 extra hours of talk time, 6 hours of Wi-Fi Internet, 7 hours of video, 24 hours of audio, or 250 hours of standby time. We tested the Juice Pack using our standardized video battery test, which uses two iTunes Store movies, places brightness and volume at 50%, turns Wi-Fi off, and outputs audio through iPhone’s headphone port, rather than its bottom speaker.
Using this test, we previously clocked our iPhone’s video performance at 7 hours and 46 minutes, a bit above Apple’s estimate. With the iPhone and the Juice Pack both completely charged, we connected them and watched to see what the iPhone would do. The icon on the iPhone indicated that it believed that it was connected to a charger, and remained in this mode playing back our test videos for 7 hours and 50 minutes. At that point, the icon disappeared, and the iPhone continued to play back videos for 7 hours and 44 minutes before bleeding dry of power; like the iPod touch, it crashed during video playback when it reached its 20% and 10% battery remaining points, but ultimately ran for twice its standard time.
iPhone’s other modes will also see a doubling of their standard run times, as well.
Juice Pack’s performance is solid: shy of the UPB10, but without question, enough to keep an iPhone running way longer than it could unassisted. Mophie’s pitch is that it’s “powered up and ready to go – straight out of the box,” conceivably enabling you to buy one in a store and guarantee that you can power a dying iPhone on the spot. Our sample arrived in full packaging with only a 50% charge, however, and given natural rechargeable battery depletion over time, it’s unclear how juiced up the Juice Pack will actually be when you get it.
Our two biggest concerns about Juice Pack relative to the flat B-rated UPB10 are build quality and pricing. By the standards we’ve come to expect from iPod accessory makers, our review sample came out of the box looking pretty unimpressive, with less than precise green coloring touching the otherwise black casing, and highly visible seams between the front and rear parts of the accessory’s shell. Blemishes in the soft rubber finish were also immediately visible. Mophie tells us that we’re the first people to receive a unit with these issues, and that buyers shouldn’t expect to see them, but given that our Juice Pack arrived in finished but arguably underprotective packaging, we may not be the last. Because the marks are only cosmetic, we’re not giving Juice Pack our automatic D- rating for defectiveness; they just detract from the unit’s appearance.