Impact of extreme climatic conditions on fast EV charger performance: field experimental insights from Qatar

This study presents in situ experimental assessment of a commercial air cooled DC fast charger operating under Qatar's extreme desert climate, with ambient temperatures crossing 15–55 °C. High resolution field measurements were used to evaluate the coupled effects of ambient temperature, rectifier temperature, offered and delivered power, conversion efficiency, input current harmonic distortion, and EV battery state-of-charge evolution. The results show thermally induced derating: the charger maintained near rated output under moderate thermal conditions but experienced a rapid reduction in offered power once rectifier temperature approached 55 °C. Under peak summer operation, offered power declined by up to 35–40 kW, average efficiency decreased by approximately 5–8 %, and current THD increased markedly during thermal tapering. Charging duration for the tested SoC window nearly doubled, increasing from 86 min in winter to 169 min under extreme summer conditions. The offered and delivered power comparison further recognizes charger limited operation from battery limited charging, which confirms that high temperature performance loss is primarily dominated by charger side thermal protection. Data driven thermal performance models have been developed. The models were validated using cross session and temporal hold out analyses, which accurately predict offered power derating and charging duration with respect to temperature. The findings provide validated evidence of the limitations of conventional air cooled fast chargers in hot climates and offer practical guidance for thermally resilient, grid compliant charging infrastructure, including improved cooling, harmonic mitigation, and hot climate deployment standards.