I started using a 7290 and I'm charging it by connecting it to my PC. It takes a long time though. I was just wondering how long it takes to charge it from 20% to full, for example. Thank you in advance.

It could take an hour or two depending on whether you have the device on or not? If its on, it may be searching for a signal which slows down the process.

Charging via the PC takes significantly longer than with the charger.