Technical specifications: Why does it not say anywhere what power the hard drives need when powered via USB? I currently have 10 external hard drives connected to my MacMini via a USB hub. That went well for a long time. But for some time now, 1-3 (especially one) hard drive(s) keep logging off. I suspect that in the worst case several hard disks start up together from sleep mode, causing the USB operating voltage to collapse. The power supply of my USB hub (7+4 expansion) is probably too weak. I wanted to see how much different external USB hard disks draw....but no information. (not even in the manufacturer's data sheet)
The end devices assume that the USB port can deliver the required power according to the standard.
If your USB hub cannot, then this is more the problem of the hub - less of the end device.
In this context, it is perhaps worth noting that not only the speeds have changed with the different USB standards, but also the possible amperages that a device can draw. Several USB3 devices may have problems if they are connected together to a USB2 hub.
Wikipedia has a table with the possible power ratings.
https://en.wikipedia.org/wiki...
