If your car battery UK is failing, you’ll notice one immediate effect: your vehicle won’t start as easily as it should. That’s because the battery provides electrical energy to the starter motor to get the engine turning over.

But how? The answer lies in how to compare car battery brands are constructed. In a lead-acid battery, which many vehicles have, there are positive and negative electrodes. The positive electrodes contain lead oxide plates which sit in an electrolyte, in this case, sulphuric acid and distilled water.

There’s also a positive grid, which both holds the active material and collects electrical current. That’s constructed from a lead alloy. The negative plates within the negative electrodes are made of pure lead, and the negative grid also holds the active material and acts as a current collector.

When you start the car’s ignition, it sparks a reaction between the four main materials – lead, sulphur, hydrogen, and oxygen – that converts chemical energy to electrical energy.

The batteries for cars then uses this not only to start your engine but also to power the vehicle’s lights and other electrical accessories. These are also negatively affected if your battery is starting to fail.