Full-battery effect during on-board solar charging of conventional vehicles

Abstract On-board photovoltaic arrays may reduce fuel consumption and contribute to decarbonization of road transport by feeding the electric storage capacity of a vehicle. Since the CO2 savings arising from this technology cannot be quantified by standard test-cycle CO2 measurements, additional procedures are considered to assess its performance under real-world driving. The full-battery effect, i.e., the loss of potentially storable solar energy due to battery saturation, influences significantly these savings. The objective of this study is to present a novel methodology to evaluate the impact of the full-battery effect during on-board solar charging of conventional vehicles and thereby to estimate the associated CO2 savings. The methodology is based on solar irradiance and driver mobility data. Results show that the full-battery effect can be uniquely determined by the normalized real-world solar irradiance and two dimensionless combinations of vehicle electric power consumption, solar-energy storage capacity, system efficiency, PV array peak power and inclination.