I'd like to use an external usb3 2Tb WD MyPassport 5200rpm HDD with my Raspberry Pi400 for a large Retropie project.
I think having it running powered from the Pi400 alone is not giving enough power to it: I once noticed some ext4 errors on reboot, which perhaps is caused by the lack of power.
I was thinking of using a USB 3.0 Y-cable (which I already own) to supply enough power to the external HDD: https://www.amazon.co.uk/InLine%C2%AE-USB-Y-Cable-Micro-Black/dp/B00NQHZBF8
I've been told that it might back-power the USB3.0 port of the Pi400. I've so far tested it and it seems to be running OK, and brown-outs have disappeared. But I stopped for fear of damaging the Pi400.
Can you please kindly let me know what damage could this create?
What I tried so far: I run the external WD mypassport 2TB 5200rpm HDD directly with the Pi400 and noticed some exr4 errors on reboot. Which makes me think it's a brown-out.
I run the Y-Cable plugged to a 5V-1A adapter and to the HDD and into the Pi400 and haven't had any problems.
I also tested a usb3.0 powered hub that worked well for a week and it is now causing some brown-out symptoms, so I'd like to return it and explore using the Y-Cable instead.