But here, all good. As to power, I find that if I want to charge more than one thing I can't use my PC USB port to say some USB HUB and expect to charge say my phone, tablet and portable battery.
But my powered hub (it uses a wall wart) can charge all three.
Most USB hubs have ports that are designed for transferring data rather than charging devices. But will they charge devices (like a cell phone and MP3 player) even if slowly? Will they charge devices at the same speed as the USB ports on the computer itself? Does it matter whether the USB hub is self-powered or bus-powered?