Few things in life are as frustrating as when you're already late for work, rush out to your car, and discover it won't start. The headlights are dim, and the engine refuses to turn over. At that moment, you realize that your battery is dead and you have to make the dreaded phone call to your boss, explaining you'll be significantly late. He might question how you ended up in this situation, but even if he doesn’t, it's beneficial to know what causes battery failure and how to avoid it in the future.

Batteries die for a plethora of reasons, as explained below, but being in the car industry, we notice a huge uptick in battery sales during the winter months. This is not surprising, as that is when batteries often die of old age due to increased internal resistance and reduced capacity in cold temperatures. If I were the boss, I would be justifiably peeved if your car not-starting event happened in winter because that is an entirely foreseeable and preventable problem.

The car battery is the most crucial component for starting and driving your vehicle. It sends power from the starter motor to the spark plugs, igniting your car’s fuel, while also providing power to other systems like lights, radio, and in some cases -air conditioning. You might notice your car battery beginning to die if you have difficulty starting your vehicle, experience flickering lights, or notice a weakening alarm system.

Your car battery may begin to drain for several reasons:

  1. Human Error We’ve all done it at least once—come home from work, tired and not really thinking, and left the headlights on, didn't completely close the boot lid, or forgot about some internal lights. Overnight, the battery drains, and in the morning, your car won’t start. Many new cars will alert you if you’ve left your lights on, but they may not have alerts for other components.

  2. Parasitic Drain Parasitic drain happens when components in your vehicle continue to run after the key is turned off. Some parasitic drain is normal—your battery keeps things like your clock, radio presets, and security alarm operational at all times. However, if there's an electrical problem, such as faulty wiring, poor installation, or defective fuses, parasitic drain can exceed what's normal and deplete the battery.

  3. Battery Stratification This relatively unknown problem occurs mainly in luxury vehicles that drive very short distances daily. The electrolyte on a stratified battery concentrates on the bottom, causing the upper half of the cell to be acid-poor. This effect is similar to sugar collecting at the bottom of a cup of coffee when the waitress forgets to bring a stirring spoon. Batteries tend to stratify if kept at low charge (below 80%) and never receive a full charge. Short-distance driving while running windshield wipers or heated seats contributes to this.

  4. Faulty Charging If your charging system isn’t working properly, your car battery can drain even while you’re driving. Many cars power their lights, radio, and other systems from the alternator, which can make the battery drain worse if there's a charging problem. The alternator may have loose belts or worn-out tensioners that prevent it from working properly.

  5. Defective Alternator A car alternator recharges the battery and powers certain electrical systems like lights, radio, air-conditioning, and automatic windows. If your alternator has a bad diode, your battery can drain. The bad alternator diode can cause the circuit to charge even when the engine is shut off, leaving you with a car that won’t start in the morning.

  6. Extreme Temperature Extremely hot (over 38 degrees Celsius) or cold (under -10 degrees Celsius) temperatures can cause lead sulphate crystals to build up. If the car is exposed to such conditions for too long, the sulphate buildup can damage the battery's long-term life. It may also take a long time for your battery to charge in these environments, especially if you only drive short distances.

  7. Excessive Short Drives Your battery may wear out prematurely if you take too many short drives. The battery puts out the most power when starting the car. Shutting off your vehicle before the alternator has a chance to recharge could explain why the battery keeps dying or doesn’t seem to last long.

  8. Corroded or Loose Battery Cables The charging system cannot top up your battery while driving if the battery connections have corroded. They should be checked for dirt or signs of corrosion and cleaned using a cloth or a toothbrush. Loose battery cables make it difficult to start the engine as they cannot transfer the electrical current efficiently.

  9. Old Battery If your battery is old or weak, it will not hold a full charge well. If your car consistently won't start, it’s possible that the battery is worn out. You should generally replace your car battery every 3-4 years. If old or poorly maintained, your battery may die regularly.

Diagnosing and Replacing a Battery Having a battery that won't hold a charge is frustrating, and figuring out what's causing the problem can be tricky. Assuming the cause of the battery drain is not human error, you'll need the assistance of a qualified mechanic who can diagnose your car's electrical problems and determine if it's a dead battery or something else in the electrical system.

If the problem is indeed the battery and requires replacement, make sure you know what the different battery specifications mean so that you can make informed decisions when purchasing a battery.

  • Cold Cranking Ability (CCA): This rating defines a battery's ability to start an engine in cold temperatures. It refers to the number of amps a 12-volt battery can deliver at -17 °C for 30 seconds while maintaining a voltage of at least 7.2 volts. The higher the CCA rating, the greater the starting power of the battery.
  • Reserve Capacity (RC): This is a general indicator of how long a new, fully charged battery can operate essential accessories if the vehicle’s alternator fails. It identifies how many minutes the battery can deliver a constant current of 25 amps at 26° C without falling below the minimum voltage needed to keep your vehicle running.
  • Amp Hour and C20 Battery Capacity: This indicator shows how much energy is stored in a battery. It is the energy a battery can deliver continuously for 20 hours at 26°C without falling below 10.5 volts.

A driver in a colder climate will choose a battery based on cold cranking amperes, while a driver in a warmer area chooses a battery based on reserve capacity. In South Africa, it follows that buyers should choose batteries based on their reserve capacity.

In Summary At Start My Car, we can help you with all your battery-related needs. We offer an extensive range of maintenance-free, O.E.M quality Exide batteries complete with a 2-year warranty. We also stock battery terminals, battery hold-downs, trickle chargers, multimeters, battery water, battery acid, and booster cables. Have a look at our website and feel free to contact us if you need any assistance!