ELECTRICAL SYSTEMS (a) Fundamentals (b) Auto Wiring system (c) Battery (d) Ignition System

Electricity in vehicles works like water flowing through pipes. Current flows from the battery's positive terminal through wires to components, then back to the negative terminal, completing a circuit. Think of your father's car battery as a power station storing electrical energy that powers everything from the starter motor to the headlights.

In a series circuit, components connect one after another, so current flows through each part sequentially. In a parallel circuit, components branch off separately, allowing current to take multiple paths. Your car uses both types. The lighting system uses parallel circuits so each bulb works independently, while some ignition systems use series components.

Ohm's law (V = IR) tells us voltage equals current multiplied by resistance. Understanding this helps diagnose electrical problems. A faulty alternator in a Lagos taxi might fail to charge the battery properly, causing dim lights or starting difficulties.

When electricity flows through your car's wiring, different circuits need different cable sizes—this is what we call wire gauge. A thick wire (low gauge number) carries heavy current safely, like what your starter motor needs, while thin wire (high gauge) handles smaller loads like dashboard lights. Think of it like water pipes: bigger pipes for more water flow.

Colour coding helps mechanics identify wires quickly. Red typically means positive, black means negative or earth, and yellow, brown, or green indicate different circuits. In Nigerian cars, this system prevents dangerous mistakes during repairs or modifications.

Cables join using three main methods: twisting and soldering for permanent connections, crimp terminals for quick disconnection, and connectors for complex circuits. Earth return systems use the car's metal body as the negative pathway instead of running separate wires back, saving weight and cost.

The lead-acid battery is your car's power bank. It stores electrical energy to start your engine, power lights, and run other electrical components. Think of it like the power supply in your home—without it, nothing works.

A lead-acid battery contains lead plates (positive and negative) inside cells filled with electrolyte, which is a mixture of sulphuric acid and distilled water. When you turn your car key, chemical reactions inside produce electrical current. For example, in Lagos taxis, a dead battery means no movement until you jump-start the vehicle using another car's battery.

Testing involves checking voltage with a multimeter—a healthy battery reads 12.6 volts. Regular maintenance includes keeping the electrolyte topped with distilled water, cleaning corrosion from terminals, and securing the battery firmly.

The coil ignition system is the heart that makes your car engine fire and run smoothly. Imagine it as a chain of friends passing a message—the battery sends electrical current to the ignition coil, which transforms weak current into a very strong spark. This spark jumps across the spark plugs in each cylinder, igniting the fuel-air mixture and making the engine work.

The main components work together perfectly. The battery provides initial power, the distributor directs the spark to each spark plug at exactly the right time, and the breaker points control when the coil produces the spark. In a typical Nigerian Tokunbo car like a 1998 Honda Accord, you'll find the distributor under the bonnet, connected by thick cables to each spark plug. When you turn the ignition key, this entire system springs into action in milliseconds.

Understanding how these parts connect and time their actions is crucial for diagnosis and repair.