Once known for its interesting case designs, Mophie has built a name for itself over the past couple of years as a provider of rechargeable battery accessories — slimline “Juice Pack” backpacks specific to a given iPhone or iPod touch body design. Now that Apple’s in the process of rolling out new enclosures for its portable devices, Mophie has developed several new device-agnostic battery solutions, including Juice Pack Reserve ($40), which takes a different approach from its predecessors.
Made from metallic silver and matte black soft touch plastics, which contribute to a lightweight and somewhat inexpensive feel in the hand, Reserve is designed to be carried around separately from the iPod or iPhone. You can optionally attach it to a belt loop or bag with an included carabiner hook, pulling it into use only when extra power is really needed—hence the “reserve” part of the name.
A retractable Dock Connector plug is on one side, with a port for recharging the 1000mAh battery on another, and a USB cable is included so that you can refuel it using a computer. This combination of features places it in the same general category of simple battery packs as options we’ve previously reviewed from Kensington, Just Mobile, Dexim/RichardSolo, and others.
Also worth noting is Reserve’s shape, which at roughly 1.7” wide and 3” tall does protrude from the iPhone’s or iPod touch’s bottom—and partially cover the lower speaker and microphone on an iPhone—though the impact on speakerphone performance turns out to be minimal; attachment of the accessory lowers the apparent volume only a little on both sides of a call. Juice Pack Reserve also has one of the gimmicky add-ons found in some Dexim/RichardSolo and off-brand OEM-sourced batteries: holding down a button on one side activates a small LED flashlight, with just enough illumination power to barely show you the path ahead—your iPhone or iPod screen can do much better. Tapping the same button shows up to four white light indications of the unit’s remaining power; Juice Pack Reserve turns these lights on automatically during USB recharging to let you know how close it is to full.
Based on the 1000mAh rating, which is roughly 2/3 the size of an iPhone 4 battery or 1-2 times the size of batteries in most iPods, depending on the model, one might expect a charge along those lines.
In our testing, energy lost in the transfer process meant that a completely discharged iPhone 3GS with a roughly 1200mAh battery actually recovered only 53% of its power from Juice Pack Reserve. As with virtually all iPhone/iPod batteries, you’ll come closer to this one’s full recharging potential when it’s paired with a device that still has some of its original battery power left, but Mophie’s choice of a 1000mAh cell is on the low end of standalone rechargeable battery units we’ve tested.
But then, the price is lower, too, and ultimately, Mophie is hoping that both the atypically low $40 tag and the convenience factor of having a belt hook and slide-in Dock Connector plug will make up for its weaker run time. Overall, we’d call it roughly par with the good but not great batteries we’ve seen for the iPhone and iPod, a “get what you pay for” option that has commensurately less longevity than the more common $50 1200mAh batteries offered by companies such as Dexim/RichardSolo, and the same as the now $40 Kensington Mini Battery Pack and Charger. It also falls well below the run time of Just Mobile’s famous Gum, but includes the Dock Connector that Gum leaves you to self-supply.
