SanDisk 2TB Extreme Portable SSD… 1 being used for cloning (formatted APFS) and 1 for Time Machine backups (formatted HFS+).
When connected to my MacBook Pro, using either a TB3 or SanDisk’s provided USB-C cables, the SSDs heat up, in the lower half of the SSD where cable connects, more than I would expect, regardless whether actively working or simply connected but dismounted. [The SSDs are laying flat with the top (perforated) side face-up; so, heat easily escapes.]
It seems logical the SSDs would heat up when actively reading/writing, but I would expect the SSD, when not actively working, to cool down from the heat level it reaches when actively read/writing. The SSD (even when connected, but dismounted) maintains the same heat level rather than the heal level lowering.
The amount of heat is notably warm - almost hot, but certainly less than really, really hot; so, somewhere between really warm and a lower threshhold of hot. …If I disconnect the SSD, the heat level completely drops off.
Long term & reliable SSD usage seems will be best by disconnecting it after principal tasks have been completed, in order to control the SSD from long periods of being overly warm.
I had intended to actively use these SSDs and then, dismount them (keeping them connected), as I’d like to avoid continual, cable disconnecting / reconnecting that might cause deteriorating wear of the USB-C port. …Am I correct these SSDs are not designed for continual, cable connection to the computer source?