How the battery and the motor of the car work together is surprisingly simple – the battery connects to the ingition, which in turn activated the combustion engine. When you press the accelerator, the vehicle instantly feeds power to the engine. Electric dynamos work as generators during forward motion, taking your foot off the throttle, the car/vehicle begins to slow down by converting its forward motion back into electricity – this also happens when you hit the brakes on more modern vehicles. To maintain the life of the vehicle battery, manufacturers ensure that there is additional spare capacity to compensate for degradation over time. As the battery ages and cycles, additional spare capacity is used. This allows the range of the vehicle to remain the same for the entire battery life. Once the battery capacity falls below 80 per cent, the driver may begin to notice a drop in the battery range and performance.