It is my understanding that there will be 5 batteries on the semi. Why not Just have 2 batteries on the truck so it weighs less without a trailer and could be smaller and then build/retro fit 3 batteries on or under the trailer, that way the trailer could be charged while waiting to be picked up and the charging port could be at the rear of the trailer so that the charging station could be in the loading doc and out of the way of the drivers when they back in to pick up or drop off loads. Also it would be easy to only install the needed number of batteries depending on the distance needed. They could easily be added and taken away or changed out with a electric fork lift. Maybe my industial design degree is kicking in.. lol. This idea is worth millions.