In this paper we study the power characterization of a skid-steered mobile robot operating both indoors and outdoors, taking the 3D elevation of the environment also into account. We show that the power equation of a driving DC motor together with the force model on an arbitrary terrain can be used to estimate the power consumption as well as the effective friction coefficients of a skid steered vehicle. We present a mathematical model that estimates friction due to skid as a function of slip angles, and the radius of curvature. We present experimental measurements and their statistical summaries regarding the power consumption of a skid steered robot operating at different radius of curvatures, which can be used for rough motion planning, as well as experimental results showing the fitness for our model.