Why the right car battery is no longer just about engine size

For years, buying a car battery was one of the simplest decisions for motorists: match the size, replace the old one and drive on.

But that simplicity no longer holds.

According to Charles Ngare, General Manager at Chloride Exide, today’s vehicles have evolved into far more complex machines, and that shift has changed how batteries should be selected and used.

Modern vehicles now depend heavily on electronic systems that demand more power, more stability and more intelligence from a component many drivers still treat as basic.

Unlike older models where batteries mainly served to start the engine and power basic functions, today’s cars run multiple electronic systems at once.

These include safety and driver-assist features such as lane departure warnings, blind-spot monitoring, adaptive cruise control and multiple onboard cameras. Comfort systems like heated seats and massage functions also add to the load.

This shift, Ngare says, has turned the battery from a simple starting device into a core part of a vehicle’s operating system.

One of the biggest disruptors in battery design has been the introduction of start-stop systems.

According to Ngare, these systems automatically switch off the engine when a car stops and restart it when the driver moves again, improving fuel efficiency and reducing emissions.

But that efficiency comes at a cost: repeated engine shutdowns and restarts place far greater strain on the battery than traditional driving conditions.

Different battery designs

To keep up with these demands, battery design has evolved in stages.

The first shift was from vented batteries, which required regular maintenance, to maintenance-free batteries designed for convenience. "Then we moved away from that to something more convenient. Less maintenance. And that's maintenance-free. Whereby you just fitted it and forgot about it,” said Ngare.

But as vehicles became more advanced, even maintenance-free batteries were no longer enough.

Two newer technologies emerged. Enhanced Flooded Batteries (EFB) and Absorbent Glass Mat (AGM).

EFB batteries are designed for vehicles with moderate start-stop systems and moderate electronic demand. In contrast, AGM batteries are built for higher-performance vehicles with heavier electrical loads and advanced systems.

"Then the AGM battery came in to handle cars, basically premium cars with advanced driver assist systems, higher-end electronics. And it has four times the cycle life of a standard battery. The main differentiator between an AGM battery and the rest is that an AGM battery, unlike what we have traditionally known batteries to have inside, that is the diluted liquid electrolyte, the acid,” said Ngare.

According to Ngare, a common mistake motorists make is selecting a battery based only on engine size.

He says that even if a wrong battery is fitted, the car may still start, but some systems may not function properly.

"What normally happens is that if you fit the wrong battery, at times the car may work. It will ignite. It will light, you know, basically the basic systems of a battery. But certain advanced systems are going to be switched off by this car.”

He adds that most modern vehicles have a battery management system that constantly monitors performance. If the wrong battery is detected, comfort and safety features may be deactivated.

Even with the correct battery, some functions may still not work until the battery is registered with an OBD2 diagnostic tool, as modern vehicles adapt to battery performance over time.

"You have to tell it, now reset all these electronics because I have a new battery,” says Ngare.

Installation 

Ngare also highlighted simple installation practices that remain critical.

He advised that during removal, motorists or mechanics should disconnect the negative terminal first, then the positive. When installing, the order should be reversed: positive first, then negative, because the negative is where the power rests.

He also warned against hammering battery terminals, explaining that the terminal holds internal cells in place and forceful impact can damage them, eventually causing the battery to fail.

As vehicle technology continues to evolve, Ngare says motorists must rethink how they approach something as routine as battery replacement. What was once a simple swap has now become a technical decision tied closely to a car’s electronic systems.

For him, the message is simple: understanding your battery is no longer optional; it is part of understanding your car.