NUC 8I3BEH - power consumption

You can find real world figures here:

However, they dont take into account the possibly higher requirements for the boot process, and if you’re powering portable USB drives or other USB equipment etc.
I can tell you that an sBooster 15-16.5v CANNOT power the NUC8i3 when the Ultra adapter is involved. (Without the Ultra seems to work, but can be a bit unstable)