recharge the battery while breaking and remove mechanical brakes
the idea seems obvious but the implementation is not trivial. normally, to slow down the rotation of wheels we'd need to induce the electro-magnetic field of the opposite direction and spend some battery's power. my idea is (assuming that the the inductor is rotating inside the static magnets): to get the massive magnetic system rotating while the car is accelerating, and use this magnets to induce the "breaking" electro-magnetic field on the rotating inductor connected with driving wheels; considering the inverted design (if Smart's transmission is not a "classic" one but with static inductor and rotating magnets): add another "passive" inductor rotating with the wheels which will be activated while breaking (mechanically inserted into static magnets while braking); the 10kg weight of mechanical braking system will move into the motor, hopefully charging the battery also; precession aware (is the driver gyro-aware? haha)