Hooking up my philips dvdr16ls and a hard drive one the same caddy?



I have opened up my hard drive caddy and put my philips dvdr16ls in it so its working on usb. I notice that the connections are the same as in a pc. As the top is off could I hook up a doubler on the power plug and a standard pc drive connector so I can run the hard drive and the dvdr of the same supply. Do these things draw much power - what would happen if it was too much draw? It would be useful to do as I am all out of usb ports and space wise it would be a neat option