Can I recharge my Android smartphone at any USB port? My girlfirend has just installed a new CD Player on her car that comes with a USB port to connect external devices(Flash card, external hard drive, etc). My question is based due the fact that I told her that if she want to recharge her Android smartophone on her car, she must buy a 12V car adapter to USB(which is very expensive on Brazil). Now, with the new CD Player, I'm wondering if she can use it's USB port to recharge her cellphone with the USB cable. It is feasible? There is any limitations on recharging an Android smartophone on another types USB ports(I mean from another host not only the CD player)?
There're two flavors of USB ports - powered and unpowered. Unpowered ports can't supply power to the devices and are rather rare. You identify them easily - connect the smartphone to them and see if it starts charging. If it starts charging the port is powered and you're okay.