I have successfully charged a empty battery with hybrid USB

[purezerg]

i made a cable, that has 2 USB-A at the computer end and the other end is a USB-B + firewire.
the cable has got a boost that converts USB to 12v.

i have successfully charged 2 empty BP915 batts with this method.

the boost circuitry is a little on the big side. 4cmx1.5cm

I wonder how many people are actually interested in such a cable.

I haven't tested it on a MBP or any mac.