I have 2 USB hard drives that combined take too much power to run through the pi USB port.
I have several 5V sources laying around that provide plenty of current for all of the hard drives and raspberry pi combined.
Could I wire up the USB any of these two ways to power the hard drives via the external source?:
In the first case, the Hard drive power is in parallel with the USB power. In the second case, the pi power is disconnected and the external power is connected directly to the HDD.