Please consider the difference between "Portable" drives, and "External" drives.

Portable drives are powered only from the USB ports (though some also can use an external power supply, specifically SimpleTech). They use a split USB cable that provides data and power, and a second split-off USB cable that can be used with a second USB port if the drive doesn't power up correctly. I.e., the second cable is power only.

These portable drives use slow 2.5" disks, and my experience (with dozens) is that they are amazingly fragile, and they may be subject to heat issues.

External drives use a separate power brick, are likely to be faster, and are probably better engineered for heat and power issues.

Bottom line here: Don't use a "portable" drive unless it's absolutely essential, and in that case, consider them only for porting, not archiving, purposes. Any data you really want to preserve should be saved some other way.