Though 150 KWH isn't usable for propulsion I did some calculations and a 20 lb bottle of propane has 126 KWH of energy. Another example of how poor ICE engines are. I can fit almost 3X the energy of the battery pack in the way back, but good luck getting 300 miles of range out of a 5000 lb ICE with that little fuel. I did have a Tesla moment getting the propane. On Memorial Day weekend I had the car towed to the same shop because I got a bad flat. The guy who filled the propane bottle was the same guy who fixed the flat. He was extremely impressed by the car when he drove if across the parking lot after fixing the flat. .