NUC8I7BEH Offically Input DC 12V-19V(±10%)
is 10.8V-20.9V the specific input dc voltage?
I have a power bank that outputs DC 10V-12.6V 150W Max
Is it possible to operate the nuc8 with the power bank?or how min voltage can operate the nuc8?
Yes, it is possible, but I would make sure that you set it to output at its highest voltage.
When people ask about running on batteries, I always recommend that they look into getting a DC-to-DC "Buck" Converter, which can convert the voltage to 19V and eliminate any drift. Here is an example of such a device (one that was developed specifically for NUCs): Mini-Box.com: DCDC-NUC, 6-48V automotive power supply for NUC, 12V or 19V output.
Hope this helps,