A car battery is an integral part of your car’s ignition system. Without it, it is virtually impossible to start the engine. Once the engine is running, the alternator takes over to supply the car’s electrical needs while restoring the charge to the battery. The car battery is also used to power devices like lights, clock, radio and alarms when the engine is off.

You can prolong the life of your battery by getting into the habit of turning off all lights, rear window heater and radio before you switch off the engine. You can also learn to carry out basic battery maintenance yourself.

Types of batteries

Some cars come with maintenance-free batteries which can be identified by their flat top with no openings. Such batteries are sealed and should not be tampered with. There is usually an electrolyte indicator or “eye” at the top of the battery case to show the state of charge as indicated by the electrolyte level.

Each electrolyte level will be indicated by a specific colour shown on the eye. You have to periodically check the colour indicated to ensure that the battery is not discharged, showing a black or clear eye.

For older car batteries with removable cell caps, periodically open each cap on the cell to check that the electrolyte has not dropped below an indicated level. You can buy a bottle of distilled water at any petrol station to top up the electrolyte level in the battery cell to keep it at the right level.

Battery maintenance

Start with a visual check around the casing and cover for any cracks and other physical damage. A cracked battery needs to be replaced immediately as the electrolyte in a battery, a mixture of sulphuric acid and water, may leak. Any sign of moisture and a strong, sour smell from the battery indicates a leak.

Check for corrosion and deposits at the terminals or battery posts and cables. The first sign of corrosion is the presence of greenish-white crystals. The cables should not be damaged or frayed.

The top of the battery should be clean and dry. Keep the casing clean by washing it with hot soapy water and drying it properly. You can coat the terminals with some petroleum jelly to prevent corrosion.

Inspect the hold-down clamps and battery tray for damage and corrosion. Tighten any loose clamps as vibrations from the moving car can damage the battery’s internal parts and shorten its life.

For batteries with removable cell caps, check the water level every other month. If necessary, refill till the water level is below the bottom of the battery cap. Use only distilled water as tap water contains minerals and trace elements which could corrode the terminals.

CAUTION: When inspecting the battery, keep all sparks and flames away as a battery gives out hydrogen gas, which is explosive. Remove metallic objects like watches and rings to avoid contact with the battery terminals and possible electrical arcing.