We've come to rely on USB as a universal data interface, especially as more devices use standard USB ports for both data and charging. However, you can be unpleasantly surprised to discover that USB is not a universal power interface. It turns out that more sophisticated devices like the Apple iPad, some smartphones, and Flip camcorders charge fine when connected to a computer, but not with common USB wall or car adapters.
So we'll be seeing more devices like the recently-reintroduced ZAGG ZAGGsparq 2.0 portable USB charger and battery, which includes two USB ports -- a general port for charging Standard USB devices, and an optimized port to charge the iPad, iPhone, and similar devices.
Plus the ZAGGsparq is not just a wall charger, it also contains a battery with enough capacity to deliver four full recharges for the iPhone, or charge iPad from 0 to 60%, and at same rate as iPad wall charger.
The design with battery is a bit chunkier than a plain USB wall adapter, at 3 1/2 x 3 1/2 x 1 inches and just over 8 1/2 ounces. It has LED status lights to show the charge level, and pivoting power prongs that fold into the unit for travel.
The ZAGGsparq 2.0 is available for $99, to help keep your smartphone or iPad running during a long and busy day away from wall power.
See my Portable Power Accessories Gallery for more on portable chargers
Find the ZAGGsparq Charger and Battery on Amazon.com