As a guy who drives, you should know your car battery is needed to start your engine and if the batteries fail, you need to know which type and size battery you need for replacement from the nearest supply shop.
Car junkies know the average 12-volt automotive battery has six compartments or cells filled with a solution containing sulfuric acid and distilled water. Each cell has a series of alternating positive and negative plates separated by isolators. Each positive and negative plate in the battery is connected and has lead sheeting that is bonded to it.
When the battery supplies electricity, electrolytes react with the lead to form lead sulphate. As it charges, the acid is returned to the electrolyte and the lead sulphate is converted back into active material in the plates. During this cycle, hydrogen, and oxygen molecules evaporate out of the electrolyte. This is the main reason car batteries need topping up with distilled water. Continuous charging and discharging washes lead off the plates and these build up at the bottom of the battery. This is why plates short out and batteries die.
Maintenance-free batteries found in most new vehicles have thicker plates and more electrolytes which make them more reliable and last longer than the older version. Maintenance-free batteries must not be topped up. Once the electrolyte evaporates and the plates are exposed, the battery is dead.
Gel-type batteries, meanwhile, have gelatin-like electrolytes which are not lost through evaporation. However, the gel requires the use of thinner plates for proper distribution which can be shaken apart in rough driving if the gel battery is in marginal condition.
Recombination batteries are a new type which allows the gases formed during charging to be recombined. As a result, electrolyte concentrations are kept to their optimum levels. These batteries are completely sealed, do not need topping up, and come with either liquid or gel-type electrolyte. The lead do not get sloughed off to the bottom of the plates and these are generally tightly packed. The result is a powerful, compact battery with quicker charging time and a longer lifespan--but you have to pay higher.
Batteries are rated by ampere hours (Ah), cold cranking amperes (CCA) and reserve capacity. These ratings tell you how much power a battery can produce, especially under marginal conditions.
Ampere hours rate how much current can be drawn from a battery over a 20-hour period without voltage dropping below 1.75 volts per cell. A healthy battery should keep the parking lights lit for 20 hours. If you're into listening to your audio system or using other accessories without the engine running, this is an important measurement.
Cold cranking amperes, meanwhile, rate a battery's ability to start an engine in cold conditions. Fortunately, this is not an important consideration in warm Malaysia.
Reserve capacity, measured in minutes, tells how long a battery can keep the engine going if the alternator fails. To test, 25 amperes are drawn from the battery for as long as voltage does not drop below 10.5 volts. Any car battery should have a reserve capacity of at least 120 minutes, so you can always make it home.
When buying a car battery, get one rated for your vehicle and all the accessories it uses. This means a high Ah and high reserve capacity. To be sure of the quality, purchase a name-brand battery and make sure you have a warranty for it. Your car won't have a pleasant relationship with batteries that are poorly assembled and use inferior materials. In the end, it might leave you stranded in the middle of nowhere for your stinginess.