An electric motor powered vehicle includes an energy reservoir provided by a battery-mass flywheel having a diameter approximately equal to the vehicle lateral wheel spacing, allowing a compact configuration. The flywheel may include a pair of counter rotating wheels mounted on concentric shafts and may be enclosed in a containment device. A shoe-rail electrical connection facilitates transfer of current to and from the batteries. The flywheel may include fuel cells charged from a remote hydrogen source. Flywheel, alternator and friction braking may be controlled by pedal movement. Energy may be transferred to the battery mass flywheel independently of vehicle motor drive. The motor-flywheel drive connections are made through inputs to a differential gear drive. The fuel cells may charge the batteries, and a second alternator may recover flywheel energy at vehicle shut-down.