Hi Mikejin
I do not know the thermal eye, but as far as i can see it can take from 9-32v, so your battery pack should be fine.
The hd dvr is rated at 5-32v so battery pack fine here to.
in generel i have experience in wirring up theese mini dvr`s - but not your thermal eye, so please check the schematic, and try to get some second hand oppinion :-)
You can also try to google "fpv setup" in general (as long as the thermal eye have direct video out) it is the same setup as "fpv"
I hope you get it to work and "catch" some bats :-)