How it works

In a traditional vehicle, a 12-volt battery—often located in the engine bay or under a cover in the trunk—is responsible for supplying juice to a starter motor that spins the engine to life. Once the engine is running, it powers an alternator, a tiny generator that turns the engine’s rotating mechanical force into sweet, sweet electrical energy. The alternator usually powers accessories such as headlights and wipers while the vehicle is on the move, and it also recharges the battery. Electric vehicles (EVs) are powered by massive lithium-ion batteries—often positioned under the car’s floor—but they also have a smaller 12-volt battery to power accessories such as headlights, windows and wipers.

Know the signs 

A 12-volt lead-acid battery (as found in most cars) usually has a lifespan of three to five years, but drivers should always be on the lookout for signs of failure. Those include warning lights on the dashboard, dim headlights, a sulfur or rotten-egg smell, a weird-sounding horn, and corrosion, which looks like white or blue-green gunk on the battery itself. A dead or dying battery can (although not always) point to a problem with the alternator. Alternator failures are less common than battery issues, but signs to watch out for include a whining or growling noise from the engine bay, a burnt-rubber smell, and flickering or dim headlights.

Battery tips

To avoid battery problems, don’t run your vehicle’s accessories for an extended period while the engine is of, and check that you haven’t accidentally left the vehicle’s lights on before walking away. 0f your car will be parked for an extended period, consider installing a “smart” battery charger/maintainer to keep it in good shape. The best way to prevent a dead battery, however, is simply to use your car. Try to drive for at least 20 to Ħ0 minutes once a week. 0f all else fails, CAA Mobile Battery Service will test, replace and recycle your old car battery from your home, workplace or even from the side of the road.