I'm primarily a natural light photographer, but I do own a set of ProFoto strobes I got a deal on, used of course. The only bad part is that are not compatible with a battery system, so taking them outside of my garage/studio is not going to happen unless I have 20,000 feet of extension cords. So I'm thinking of getting a 300 W/S battery powered moonlight to use outdoors as fill light. My question is, if I shoot through, or reflect off an umbrella will 300W/S be enough to use as a fill light? It puts out a GN of 190, and I expect to be 10-20 feet away from the subject.

I would love to spend more $ on a good light, but I don't do much location work to justify the price.

Thanks!