Review: Just Mobile Gum and Gum Pro Portable USB Power Packs

September 19, 2008 3:30 pm UTC
by Jeremy Horwitz

There are times when Apple’s iPods and iPhones — particularly the iPhone 3G — desperately need more power. Over the course of a couple of cross-continental trips this month, and two multi-hour power interruptions at our homes, we’ve found ourselves depending on external batteries again to keep our iPhones running. The ones we’ve been testing are Just Mobile’s Gum Portable USB Power Pack ($40, aka PP-07) and Gum Pro Portable USB Power Pack ($60, PP-08), which have one major advantage over competitors: they offer a lot of power for the dollar.

The standard Gum crams a 2200mAh battery into a plastic shell the size of a thick pack of chewing gum. Notably, that capacity is a little over 150% the power of an original iPhone, and slightly more than that for an iPhone 3G; both devices consume more power than any iPod currently on the market. In other words, you can can fully recharge your iPhone or iPhone 3G one full time from the Gum, and still have enough left over for more than half of another charge, while virtually any iPod can recharge two or more full times from this model. We tested the Gum with an iPhone 3G during the aforementioned cross-country flights, and managed to tap it out only after two separate days of fairly brisk use as a supplement for a single iPhone charge that we’d performed during that time.

By comparison, the Gum Pro is roughly twice the size and has 4400mAh of power, or 300% the battery capacity of an original iPhone. This means that you can recharge a fully depleted iPhone roughly three times from the Gum Pro. Users of the iPhone 3G will get closer to 3.5 charges out of the device, while iPod owners can get even longer run times: the original iPod touch, for instance, can be fully recharged nearly 5 times from the Pro version, or 2.5 times from the original Gum. We tried the Gum Pro when we ran out of iPhone 3G battery life during one of our power outages; it had enough juice to completely refill the iPhone, and still showed two out of its three lights to indicate that it could do a couple more full charges if necessary. By iPod and iPhone battery standards, it’s a monster.

It’s worth noting at this point that there are many other iPod and iPhone batteries out there—Kensington’s $50 Mini Battery Pack and $60 Portable Power Pack, APC’s $70 UPB10 Mobile Power Pack, and Mophie’s $100 Juice Pack, just to name a few. But Just Mobile’s value is a lot better. At $40, the standard Gum actually offers more power than most of these other options, including the $100 Juice Pack. The $60 Gum Pro offers way more than any of them. Both use shapes that we found easy to hold and carry, too.

There’s only one caveat that you’ll need to bear in mind. Like most competitors, but unlike the iPhone or iPod touch-specific Juice Packs, both Gum and Gum Pro are device-agnostic; they connect with a cable to your iPhone or iPod rather than strapping on to its back. And you have to supply that Dock Connector to USB cable yourself. Once they’re connected, you just flip an on/off switch and watch a three-level power indicator to make sure there’s still juice left. The only other item Just Mobile includes in the box is a USB cable designed to recharge the battery, which you connect up to a computer or any USB wall adapter you already own.

From our perspective, the value offered by these batteries makes them both highly recommendable options when viewed alongside their competitors. Their compact sizes, large capacities, and reasonable prices make either one of these options the sort of battery pack that we’d want to have around as a spare—the fact that you could have both for the same price as a Juice Pack, and wind up with roughly 4 times greater capacity, speaks for itself. Consider these a very strong option if you’re in the need of extra fuel for a roadtrip, or just a way to keep your iPhone going in case of an emergency.