The transportation sector is moving towards a green future with a rapidly growing EV market and consequently, the demand for EV chargers is rising too. With the increased interest in 800V batteries and the current presence of 400V and 600V batteries, the voltage range for EV chargers is wide (150V-1000V). In this thesis, a wide-output EV charger based on two DAB converters with series-parallel output is proposed. A novel method of reconfiguration is introduced to allow live transitioning between series and parallel mode. The circuit of a 25kW converter is optimized to achieve optimal efficiency during a charging cycle. A comparison between advanced DAB modulation strategies is made and Triple Phase Shift (TPS) modulation in combination with Minimum Current Stress Optimization (MCSO) improves the efficiency of the DAB at low voltage and low power operation. The converter operates at >97.6% efficiency in the full range of 150V-1000V with a peak efficiency of 98.8%. A 25kW converter is modelled and simulated in PLECS, and a 200W hardware prototype is built to verify the new method for live transitioning.