1. There is now talk about a Tesla Semi with a sleeper. Is that needed for a 600 mile rig? 2. Tesla is suddenly very secretive about its charging set up when it seemed that past conference calls with comments from Musk and Straubel closed the book on that- but Musk did talk about upping the range. 3. The roadster has a ton of range- seems like going with more of a X 100 D econo range type set up where the acceleration goes down a bit might also help enable a longer range truck- after all the Tesla Semi is way way faster than the most powerful diesel semis under full load up grades and from a stop. Automotive Engineer Randy Carlson predicted a 1000 mile Tesla Semi was possible and laid out the case for it here: https://seekingalpha.com/article/4127262-tesla-semi-revisited
Just adding solar panels to the trailer could add quite a bit of range, might be able to get another 150 miles of range a day.
