How much time do I need to budget for grant preparation?
I am a mid-career physicist at a national lab looking to move to a lower COL area closer to family where being a single-income family is more viable. I didn't have luck with faculty applications in this last cycle due to lack of teaching experience (I had a pair of zoom interviews with top-ranked engineering programs, but didn't get invited for on-campus because I have never taught classes, although I have advised grad students).
I was told by one of the universities that they would be willing to bring me on as a research professor, provided I could bring in enough funding to establish and maintain my lab. Colleagues have warned me that doing so would likely require ~20 hours per week working on grants alone, above, and beyond regular work.
Is this a reasonable amount if I assume that I'd need to bring in at least $6-700k per year (myself, a lab tech, and 2-3 students)? For professors, how much time do you typically spend on grant applications, updates, etc?