Yes, I new what the peltier device was and how it worked quite well. But solar power to charge a battery is free in the long run, so the inefficiency compared to other options didn't matter. It was just going to be too small. And you may be right about propane, but it must be replaced at who knows how much in the future? I know what a panel costs now, and I know what a battery costs now. Things do wear out and need to be replaced no matter what, but I know the sun should still be free for a few more years. Plus trying to take a 20 gal. tank of propane into a large event may just raise a few red flags, where as you can just open the case to show its just battery's. This is why I want to keep it safe, portable, and powerful.