While a car’s most basic functionality i.e., moving, is powered by fuel, the many electronic systems inside a car are powered by a battery which uses the motion of the vehicle to recharge. The vehicle’s electronic systems have become more advanced over the years, with the earliest cars having no electronics to the latest cars depending on it entirely for everything from steering to brakes. Each component of the vehicle’s electronic system is connected to the battery’s positive terminal by one wire and to the negative terminal through the car’s metal body. This completes the circuit and allows electricity to flow from the battery to the device.
The vehicle battery is usually a lead-acid accumulator which uses a chemical reaction between the two terminals to generate power. This reaction is completely reversible, which allows the battery to be charged. The battery in a vehicle is charged by a dynamo which converts the kinetic energy of the car into electrical energy which is stored as chemical energy in the accumulator. Most vehicles use multiple batteries, which are connected to each other, and one battery is used to power the starter motor, and the other for every other electrical component, which ensures that there is always enough power to start the car. However, when the batteries are connected with other elements, current from the battery with the higher charge would flow into the other. To prevent his a device that restricts the flow of current in one direction, such as Redarc Battery Isolator is used. This enables charge to flow in only one direction between the multiple batteries and the alternator.
The electronic systems in a vehicle can be categorised based on functionality. Most modern cars have several subsystems powered by the battery and working independently of each other. In modern vehicles, a greater degree of subsystems depends on electronics as opposed to mechanical systems found in older vehicles. For example, steering and brakes are electronically controlled on almost every modern car. This also gives remote locking, and key-less ignition capabilities.
The engine electronics are responsible for the smooth operation of the vehicle by monitoring various metrics and controlling the engine to ensure effective and efficient combustion of fuel. Throttle control, fuel injection rate and air intake are examples of the factors that can be controlled electronically.
Safety and warning systems are also powered electronically. These work by having sensors on critical parts of the car and informing the driver of any issues through a light in the dashboard. Examples for this include brake indicators, fuel indicators, and the infamous ‘check engine’ light.
Entertainment systems are also powered by the battery, and include radio, navigation and in modern vehicles the user interface display in the dashboard or seats.
Passenger comfort systems consume the most electronic energy in a modern car and the most prominent example of this is the air conditioning system, which is available on almost every car and is used extensively. Other examples include powered windows and door locks.