I think there might be a bit of a misunderstanding in this one, no flashlight is more powerful than the sun. The thing you're looking for instead is intensity or concentration of light, a weaker flashlight able to focus its beam on a small target made out of a material which can soak up as much energy from it as possible is more effective at setting fire to something than a gigantic ball of plasma many times our planet an unfathomable distance away.To try out my eclipse glasses, I held them up to my Fenix PD35. Its 1700 lumens quickly melted a hole in the thin plastic. I believe that at a short distance, a powerful flashlight is brighter than the sun.