Car charger compatibility

[Pacific Coaster]

Hi
I have a TT1 car charger, it has a USB mini B plug on the end and produces 5v. I am wondering if I can use it to charge my TTRV2? The TTRV2 has the mini B socket for connecting to my PC and while connected to the PC, will charge via the USB port. Just trying to save a few dollars.
Pacific Coaster

 

[Schintzel]

Unfortunately the R2 does not charge via the usb socket.
Not sure why TT made it this way but pc usb sockets are normally limited to 0.5 amps@5V, the supplied mains charger is 2.0 amps @5V. So if it did work charging the TT via a pc would take 4x as long.