Lighting 101: Be the Flash
The fact is that modeling lights need lots of juice. And juice wither comes from the wall - as in AC - or from big, heavy batteries. And stop-gap measure modeling lights, designed not to use much juice, usually do not put out that much light anyway.
So, if you want extreme portability, lose the idea of modeling lights. You do not need them anyway.
You know what hard light looks like. You know what soft light looks like. So, no need for a modeling light for previewing on that front.
What you want to know is (a) where will the light fall, and (b) will there be reflections?
Reflections are pretty easy. Light works like a pool shot. Light will reflect off of a subject at the same angle (but in opposite direction) that it struck.
That is why we learned to light eyeglass wearers at an oblique angle. The reflections are still there. They are just angled to go harmlessly away from the camera angle.
You can also pop the flash and "eyeball" the scene - especially shiny or glass areas - to check for reflections, too. Just make sure you are looking from the same position from which you will be shooting.
It is easier than you think. Try it.
Now, where will the light fall? That one is different, and is the main reason most people use modeling lights.
This is another really easy workaround.
You are already used to walking around a looking at your scene from a few different points of view to choose your camera angle. (You should be, anyway.)
You need to get in the habit of doing this with your light, too. A good time to do it is while you are setting up your lights.
The difference between your camera angle and your lighting angle will determine much of the quality of your photo, so consciously considering both angles is a good habit to get into.
But, more importantly, when you are looking at the scene from your lighting angle, you see exactly what the light will see. Which, with a little practice, will eliminate your need for a modeling light.
Last I checked, (and absent your working near a black hole) light travels in a straight line. If you are looking at the scene from the same perspective that your light will see it, you become your own modeling light.
With a little practice, it is a very fast procedure. Especially if you are folding the process into that of setting up the lights.
I know it may sound a little kooky.
Just try it.
Next: Don't Let Good Light Ruin a Photo