Back in January I wrote about the "inconvenient truth" of trying to charge your iPad from a USB port: there's not enough juice.
My recommendation at the time was Digital Innovations' ChargeDr, a USB dongle that allows tablets and other devices to charge more quickly. It works (quite well, in fact), but it's a $30 solution.
If you fancy free workarounds instead, check out Asus Ai Charger. This free utility promises to charge iPhones, iPods, and iPads up to 50 percent faster using your PC's existing USB ports.
That's a pretty lofty claim: software that can boost the effective power output of hardware? It sounds almost impossible, but I'm here to tell you: it works.
I tested Asus Ai Charger on my HP Pavilion dm1z laptop. After installation, it adds an icon to the Windows System Tray, one that shows a red X until you plug in your iDevice. (Curiously, it works only with Apple products--I'm not sure why.)
Interestingly, that icon does absolutely nothing when you mouse over it or click it. The only thing that changes it is plugging your phone or tablet, at which point the X is replaced by a charge indicator.
Although I don't have the necessary electronics to measure this, Asus Ai Charger somehow enables a USB port to produce around 1 amp of power, nearly doubling the 0.5 amps of a typical USB port.
And, sure enough, my iPad charged more quickly than it did without Asus Ai Charger. I wouldn't call it fast--the stock iPad wall charger produces 2 amps--but it definitely made a difference. And it didn't cost me a dime.
Blogger Matthew Hunt conducted more concrete tests with his iPhone and posted the results here. In a nutshell, the iPhone charged just as quickly via Ai Charger-assisted USB as it did via wall charger.
Although Asus says that Ai Charger will work with all systems and motherboards, this is definitely a your-mileage-may-vary solution. Indeed, perhaps a use-at-your-own-risk one as well, given that you're dealing with ports and power output.
As I said, I've had good luck with this utility, but if you have the slightest concerns about mucking up your PC and/or iDevice, I suggest you steer clear. And if you want even faster charging from your USB ports, the aforementioned ChargeDr is worth a look.
Contributing Editor Rick Broida writes about business and consumer technology. Ask for help with your PC hassles at email@example.com, or try the treasure trove of helpful folks in the PCWorld Forums. Sign up to have the Hassle-Free PC newsletter e-mailed to you each week.