I want to run an external HDD on a Pi (currently a first-generation model, I might replace it with a Pi 3 in the future). The drive has no extra power supply apart from its USB port.
Just plugging the drive into the Pi will not work, as the Pi cannot supply enough power. It does work, however, if I insert a powered USB hub.
This led me to the question: can I get rid of the Pi’s power supply, and just plug the power port of the Pi into another downlink port of the hub, having the hub power both the Pi and the drive? That way, I would need just one power supply for everything.
I have tried plugging the Pi into the hub (i.e. hub downlink to Pi power), without the drive connected, and the Pi boots up and works. To complete the setup, I would then connect the hub’s uplink port into one of the Pi’s USB ports, and plug the drive into the hub. Will this work, or should I anticipate problems (other than the hub supplying insufficient power to the Pi)?