The aim of the paper is analysis of consumption of electric energy which is necessary to drive a farm tractor with an electric motor as a drive unit under the conditions of a drive with varied loading of the power transmission system. The object of the research was a tractor model where a combustion engine was replaced with a dc electric mo-tor. During the tests, a decrease of voltage and current strength collected from supplying batteries as a function of tractor drive time and in rela-tion to the mass of a tractor with a trailer, temperature of the surround-ing and resistance to motion were reported, which enabled determina-tion of the collected power and energy. For the used set of batteries, also the maximum range of the tractor drive on the paved road was de-termined.