Mophie was obviously on the right track when it unveiled the strap-on iPhone battery called Juice Pack last year, but some notable quality control problems and a high price took away from an otherwise smart product’s appeal. This week, Incase released the Power Slider Case for iPhone 3G ($100), a product very obviously inspired by Juice Pack, sharing most of its features while improving on some, diminishing a major one — run time — and falling a little short of greatness of execution of others.
Both Juice Pack and Power Slider start from a smart premise: Apple’s iPhones have mediocre battery life, but it’s not always convenient to carry a spare dangling battery and/or charging cable around. So instead, these are custom-molded back-mounting batteries, formed like huge rucksacks with integrated, wraparound Dock Connectors. While Juice Pack somewhat awkwardly created a half-shell with pit-like grooves for the iPhone’s bottom speaker and microphone, Incase has instead integrated its battery into a redesigned—mostly thicker—version of its Slider Case for iPhone 3G.
This is a smart concept, as it gives users a combination of iPhone 3G body protection and spare power for use when traveling. Notably, Power Slider is now coated in clean, black soft touch rubber, and though there isn’t any screen protection—a continued, annoying omission from Incase’s cases—the company unusually includes a carrying bag for the case. This bag looks nice, and is useful for storage if you’re traveling, but we’d have been more pleased with a film screen cover, say nothing of integrated rubber button covers. With Power Slider on, the 3G’s camera and headphone ports are generously exposed, though the largest oversized headphone plugs won’t work with this case, and you will need to remove it entirely to dock the iPhone 3G or use it with other bottom-mounting accessories.
Fans of Incase’s slim plastic case designs may find one of Power Slider’s inescapable design elements to be less than pleasant: because there’s a battery in the back, and connection hardware on the bottom, this case roughly doubles iPhone 3G’s thickness and adds a bit to its height. Your iPhone goes from looking sleek to resembling a big black brick, and even users who aren’t thinness-obsessed may well want to remove the battery when it’s not in use.
That turns out to be trickier than one might hope.
Blame the battery. Incase has picked a 1330mAh lithium-ion polymer cell, which is claimed to be capable of more than doubling the iPhone 3G’s battery life. Notably, however, this cell has less power than the same-priced 1800mAh Juice Pack battery, say nothing of notable $40-$60 batteries we’ve tested from companies such as Just Mobile, Kensington, and RichardSolo. In our continuous tests over four days of traveling, running zero, partial, and full depletion tests of the iPhone 3G before connecting Power Slider, we either received one full iPhone recharge or fell a little short when Incase’s battery was completely charged. In other words, a power user who adds Power Slider will find that the iPhone 3G will likely run all day, rather than just for half of it.
The iPhone 3G did best when it and Power Slider were completely charged at the start of the day, connected to each other, and used such that Slider provided sips of power for the 3G whenever it wanted them. It did worst when the 3G was at 10% power and desperate for a recharge; we noticed Slider actually heating up when it was trying to bring the iPhone’s battery back to life, and only just completed a charge; it didn’t have 20-30% left to go. In other words, prepare to keep Slider attached for at least the first half of your day, and thereafter unless you want to carry a second, thinner case around as well.
There were a couple of other little things worth mentioning in Power Slider’s design. By contrast with Mophie’s Juice Pack, which looked amateurishly rough, and had rubber peeling off before we even started to use it, Incase’s use of soft touch rubber and general case design is very handsome, other than its thickness.
We’ve pocketed it for days without any problems with the rubber, and we actively liked the back, which contains five white LED lights and a recessed button to indicate power status.
Incase also includes what it says is a special USB 2.2 cable for charging of the battery. Apart from its case-matching rubber coating, we’re not going to claim to know what makes the cable special, but can tell you that recharging takes quite a few hours given the battery’s limited capacity, and the battery doesn’t seem to stay at 100% for long. On several occasions, we charged the battery fully at night, then came back in the morning to find it at only 4 out of 5 dots. We tried a test on one of these occasions and found that the iPhone 3G received something a little short of a 90% charge, suggesting that this wasn’t just an accuracy-obsessed LED design, but a reflection of quick drain when not in use. Some other cells use on/off switches to avoid this issue; in any case, we’d advise topping Power Slider off before putting it into use.
Finally, our iPhone 3G exhibited mixed interference test results. On a positive note, there were no noticeable wireless interference issues when used with Power Slider. Five-bar cell, three-bar Wi-Fi, Bluetooth and GPS all appeared to work the same whether this battery was attached or not; any difference there may have been was in no way obvious. Unfortunately, though Power Slider has an attractive plastic mesh grille at the bottom to cover the iPhone 3G’s speaker and microphone while positioning a mini USB plug for recharging, our test caller reported “profound” echoing back of his voice when Power Slider was on in speakerphone mode, some but less echoing in handset mode, and none when Power Slider was removed in either mode.