Trailer costs range

In 2 weeks I will travel for the first time with my EQE 350 with trailer and (heavy) motorcycle on holiday. Now I realize that such a trailer costs range, but it is not clear to me how the Navi takes this into account in relation to the charging points, which it recommends after the target entry. According to my understanding a certain distance must have been driven first to determine consumption data with the heavy load, in order to recommend reliable charging points on the route, or how to Does anyone have any experience?