This paper is devoted to the problem of efficient energy use on a fixed route for solar car racing. Solar cars are electric vehicles that can charge the battery while traveling using a built-in solar array. Solar car races are characterized by very long distances and prohibition of wall charging: vehicles can only be charged using solar energy. This alone creates a serious energy shortage, but coupled with the main goal of finishing in the shortest possible time, the task becomes even more complex. Thus, proper power management is the key to success. Since optimization of power management strategy is a computationally intensive process, modified route representation and use of automatic differentiation are advised to raise the performance of the optimization process. The proposed methods are implemented in the SPbPUStrat software solution, which is capable of solving the problem in a short time: this allows the strategy to be recalculated in full upon request.