I have 7 hdds that I've been using for backups of things. I don't want them all plugged in to the computer at the same time, so I've decided on only having two plugged in. for the others, I'm leaving them unplugged from usb. however, I was wondering if the powered hdds should be removed from the surge protector. are they still receiving power without the usb cable being plugged in? could having them like that damage them?