Best Portable USB Charger

Charge any small USB device, no outlet required

Not surprisingly, portable USB chargers far outnumber other charger types. In a world constantly on the move, connecting to the power grid isn't always an option. Having a device storing enough reserve power to charge portable USB devices can be very handy, especially during emergencies. The ideal portable USB charger stores plenty of juice, is able to charge multiple devices at one time, is lightweight yet durable, easy to use and delivers tons of power simply and reliably. The i.Sound Portable Power Max (*Est. $50 and up) is all of the above, and it even comes with a built-in flashlight, a "curious feature" says one reviewer.

Experts like Dactyl Anapest from iSmashPhone.com say the i.Sound Portable Power Max is a "must-have" for people owning multiple USB devices. For starters, none of the experts knows of any USB charger capable of holding so much power. Even the "smaller" Power Max, at 8000mA, packs more punch than its closest competitor, the largest IOGEAR GearPower Mobile Power Station (Est. $70), which musters a respectable 6600mA. IOGEAR's largest model also only has two USB ports, while the Portable Power Max has five, and using an included mini USB mini/micro split cable, can charge seven devices at once.

The device monitors its 2.5 amp capacity, and if it nears overload or gets too hot, a warning sounds. If it's ignored, the Power Max shuts itself down. Four bright blue LED lights measure charging level. CNET's Jeff Bakalar, who rates the Power Max "very good," says it is "lightweight, quick, and easy to use." It can recharge while charging other devices, something the GearPower charger cannot do. Most important, however, is the Power Max's performance. Dan Cohen, a reviewer with GearDiary.com, says he charged his iPhone 11 times and his iPod 18 times. "Now that's impressive," he says. Reviewer Jeff Richardson of iPhoneJD.com survived Hurricane Isaac, and he says he would have paid "top dollar" for a device like the Portable Power Max, adding that it's "a great addition to any emergency preparation and camping kit."

It's not a perfect device. Experts find fault with the five USB ports packed so tightly that larger USB dongles may be difficult to fit. Charging multiple devices at once significantly slows charging times, and the glossy case is prone to smudging and scratching. Still, as iLounge.com's Jeremy Horwitz says, "the sheer quantity of power inside this battery is amazing." Its ability to charge so many devices at once makes the i.Sound Portable Power Max a clear winner.