Electric vehicles (EVs) are rapidly replacing gas-fueled vehicles because of their advantages in energy efficiency and environmental friendliness. However, the limitations of driving range and long battery recharging time are the main challenges of EVs. Therefore, the proposed design of an in-wheel generator and intelligent DC-DC converter was developed. The rotor of the in-wheel generator with 3 pairs of magnets around it is built to fit inside an 18 inch wheel rim. In this way, a part of the energy is converted to charge the battery. However, the electricity created from the in-wheel generator is not enough for charging the battery. Hence, the intelligent DC-DC converter is utilized to determine stability. In the proposed system, an intelligent controller is built up into the DC-DC converter to change circuit parameters such as capacitors and duty cycle. The stable output voltage from the converter is utilized to charge the battery pack. This fuzzy-based controller is implemented to deal with the dynamic range of speed and battery pack conditions. The system design and performance analysis demonstrate the advantages of the energy efficiency of the proposed in-wheel generator for rechargeable batteries used in EVs.