The problem with using a USB HDD that doesn't provide its own power (by this I mean the HDD having a power brick that you plug into a wall outlet) is that not every USB port has a high enough amperage rating. All USB ports provide 5.5v, but they differ about the amount of amps provided. if a device calls for say 5.5v, or 12v, and the power supply doesn't provide enough volts the device just wont power on. if the power supply provides to much volts then you can and most likely will damage the device. Amps are different though. your power supply needs to provide the amount of amps that the device requires, or more. More amps is always better. it wont make the device work any better, but if it provides more than needed then you are for sure going to be safe. The reason why this is the case is because if the device requires say 2.5 amps, and your power supply can only output say .5 amps (500mhz) the device will try to pull more amps than the power supply can handle and something is going to burn out. most of the time it's the power supply that will fry, but sometimes it can be the device that releases that magic smoke. release that magic smoke and it will never work again. There is one last thing to remember. the HDD uses a motor to spin up the platters. When an electric motor first spins up, it uses more power than compared to when it is already spinning. To solve the peak power problem, motor drivers use a capacitor. the capacitor basically acts as a battery that can dump all of its power all at once. even ceiling fans have a large capacitor to prevent blowing a fuse, or to prevent a wire becoming too hot due to dealing with all the power the motor is pulling at peak (spinning up). So lets get back to the usb boards on game consoles. yes it does cost a little more to have a USB board that provides 2.5amps, but not so much that would create a problem for the buyers. the problem is because they never ment for said device to accommodate a USB HDD. So say one of the engineers created planes for a USB board that had that high of a rating. whoever is above him/her would say why are you calling for that? all we are trying to power is a thumb drive. You see what I meen. So even if you have a game console that will spin up your HDD, it is prolly just a matter of time before you damage the USB board. A Y cable isn't really the ideal solution either. The problem with the Y cable is that most of the time the 2nd usb slot is sharing the amps. so just because you are using the power from both usb slots doesn't mean you have taken the load off of the driver board. you might get away with it working for a little while, but it could fry it at any time. the solution is cheap. get one of these, or something like it.
https://www.amazon.com/Drive-Conver...85153394&sr=8-8&keywords=usb+hdd+power++cable
