A model simulating an autonomous battery electric vehicle system for agricultural field use was created, assuming a 200-ha conventional cereal farm in Swedish conditions. The different subsystems were verified against sources in the literature, field experiments and general common practice. The model was used to compare two different charging systems (conductive charging and battery exchange) for battery electric tractors to each other. A comparative simulation was made with conventional diesel systems (fully autonomous or manned for 10 h d−1). The simulation results indicated that battery exchange was generally a faster system than conductive charging. The results also showed that both electric systems were able to achieve similar active time during spring field operations as a corresponding system of a simulated manned diesel tractor for battery sizes from 50 kWh and charge powers from 50 kW. •A dynamic discrete-event model of a 200-ha Swedish grain farm was constructed.•Autonomous electric tractors and diesel counterparts were simulated and compared.•Weather and charging queues had high impacts on time requirements.•Electric tractors compared well with manned diesel systems in spring operations.•Battery exchange systems outperformed conductive charging in most cases studied.