A similar discussion happened over a year and a half ago, but it contained so many wild guesses and misinformation that I decided to start a new thread.
I have a Motorola Droid that charges without issue from the Motorola charger. However, I have many instances where I don't have the charger with me, but have a USB port available. But, it seems like the Droid does not want to accept charge from a normal USB port.
In my specific instance, I have a 4-port powered USB hub (2A @ 5V, meaning each port should output the USB-standard 500mA) that I use for general charging needs. This hub sits alone (i.e. no computer has connected to it), and all of the other devices I have connected to it charge without issue. I have tried with other hubs, as well, so I know that the hub doesn't have problems.
I realize that the Motorola charger outputs 850mA, at least the one I have. But, does the Droid really only accept charge in that range? I would understand if the Droid refused a 100mA current, but most other devices whose chargers output higher currents will accept a lower current (500mA), but just charge more slowly, even my Transformer!
In essence, I would like to know what I can do to cause the Droid to recognize the 500mA charging port on the hub. A firmware update? A hack?