The utilization of water resources as renewable energy through waterwheels presents an environmentally friendly alternative, however, its efficiency requires improvement through technological modification. This research investigates two design modifications: a 45° Angle Cap (AC) and a Water-Filled Angle Cap (WFAC), in comparison with a waterwheel without a Cap (WC). Experiments were conducted at discharges from 1 to 10 m³/h with a constant torque load of 0.05 N-m. The highest efficiency of 57.08% was achieved in the AC 45° configuration at 1 m³/h, generating 1.09 watts of power, while the WFAC 45° yielded the highest power output of 2.88 watts at 10 m³/h with an efficiency of 14.50%. Although increasing discharge generally led to higher power input, it was accompanied by a decrease in efficiency across all configurations. Among all three variations, WFAC 45° demonstrated superior performance at higher discharges, indicating its potential for enhancing the power and efficiency of overshot waterwheels.