Nearly four years have passed since the last time we tested one of Griffin’s TuneJuice battery packs for the iPod, and plenty has changed since then: iPods are more power-efficient than they were, Griffin’s better at accessory design than it was, and prices have gone up on iPod accessories that include Apple’s Dock Connector plug. Thus, we find ourselves looking today at TuneJuice for iPhone ($30), which does basically the same thing as the original TuneJuice, but looks nicer and sells for $10 more.

As it turns out, TuneJuice for iPhone is actually just a modestly revised version of an accessory called TuneJuice 2 for iPods, which transformed the white glossy TuneJuice into a matte black and gray box with chrome and glossy black accents. The first version depended upon a 9-Volt battery to provide extra power for an attached iPod, and this decreasingly common battery was replaced in the second model with four AAA batteries.
These same design and battery tweaks have carried over to the iPhone version of TuneJuice.
Consequently, Griffin notes accurately that TuneJuice can power an iPhone for roughly 2 hours of talk time or 1.5 hours of Internet use; alternately, it can completely recharge a totally discharged iPod nano 4G with the tiniest hint of additional juice left to spare; the batteries on earlier nanos can similarly be brought up to full- or near-full capacity. Other iPods, which use a lot more power, will get 50% or less of a battery charge from a completely fresh set of AAA batteries. Griffin supplies the first set of AAAs; you can buy replacements as you need them.
When TuneJuice sold for only $20, this made some sense, but at a $30 asking price, it’s not quite as exciting.
Given the rate at which AAA batteries can be drained, particularly in the case of iPhone use, our advice for serious users has been to invest in slightly more expensive rechargeable battery packs: Just Mobile’s $40 Gum, for instance, costs $10 more than TuneJuice but includes a rechargeable cell with five times the integrated power of TuneJuice and its included disposable AAA batteries. Since the cost to add a set of four rechargeable AAAs to TuneJuice is roughly $10, the result of doing so will be a comparably priced but far more limited charger.
We’d recommend TuneJuice for iPhone only to users who think they’ll be far away from power outlets for extended periods of time and would rather hunt for or horde AAAs than spend a little bit more up front for a more capable rechargeable battery solution.