If you're looking for a tiny, lightweight, inexpensive -- but reliable -- emergency power source for your mobile devices, reviews say the Duracell Instant Charger fits the bill. For about $25, you'll get a rechargeable battery (about 3.4 inches by 1.4 inches, and a third of an inch thick) that charges via USB. It has USB and mini USB ports, a USB/mini USB cable, and a charging indicator light -- and that's it. But that's really all you need, say several experts and consumers. Just make sure your device is compatible (most gadgets that can charge with a normal USB or mini USB connection are). The Duracell Instant Charger may not hold enough juice to recharge your gadget all the way; for example, it adds about 50 to 60 percent to an iPhone's battery in tests. If you need more power, reviews point to the Technocel PowerPak XT , which has 40 percent more battery capacity.
Gizmodo.com, The-Gadgeteer.com and AnythingButIpod.com all test the Duracell Instant Charger and report on its performance in some detail. PCMag.com briefly recommends it in a list of the best travel gadgets. User reviews at Amazon.com include both praise and criticism.
Mark Wilson calls the Duracell Instant Charger a "perfectly executed little gadget." It's small, sleek and simple, and it stores enough power to charge an iPhone "about halfway," or power just about any other USB gadget.
Review: Review: Duracell Instant Chargers Are… Pretty Perfect?, Mark Wilson, Sept. 2, 2009
Alisa Clark recommends the Duracell Instant Charger as an easy-to-use portable power source. It holds enough power to charge her iPhone from 9 percent to 70 percent full.
Review: Duracell Instant Charger Review, Alisa Clark, Oct. 14, 2009
3. Anything But iPod
This reviewer likes the Duracell Instant Charger's tiny size, low price and solid build. It charges portable speakers and music players from Philips, Sony, Archos, Sansa and FiiO as well as the iPhone in this test.
Review: Duracell Instant Charger Review, Andreas Ødegård, Nov. 29, 2009
PCMag.com recommends the Duracell Instant Charger in this best-for-travel list. The one-paragraph write-up praises the "simple and portable device" that can provide hours of rechargeable power for a low price.
Review: Fall 2010: Best Tech for the Connected Traveler, Editors of PCMag.com
With more than 60 reviews posted, the Duracell Instant Charger rates an average of 4.1 stars out of 5. Most customers love its light weight and extreme simplicity, but a few complain that it doesn't hold enough power or isn't compatible with their devices.
Review: Duracell Instant USB Charger with Lithium Ion Battery, Contributors to Amazon.com