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How Long Do Car Batteries Last


How Long Do Car Batteries Last?

Your car battery is the silent hero of your vehicle. It works tirelessly, no matter what weather is prevailing or how much you drive. But car batteries don’t last forever. On average, they last around four years. While they may seem sturdily constructed and seemingly indestructible, batteries are often not visible signs that they need to be replaced. Here are some things you should know about car batteries to ensure they keep working long enough to get you through the day.

Temperature affects battery life

One of the most overlooked factors that influence the life of a car battery is temperature. The more extreme the temperature, the less battery capacity it has. In fact, the chemical reactions that happen inside a battery double every ten degrees that the temperature increases. These chemicals are extremely damaging, and a battery that is not kept at an optimum temperature will suffer a rapid decline in capacity. High temperatures also lead to corrosion of the grid, which forms the mechanical skeleton of the active mass.

Corroded terminals

Using an old butter knife to scrub the battery terminals can help remove heavy corrosion. Hold the knife at a 45-degree angle and press it down on the terminals to clean them. If the corrosion is not removed, a wire brush or steel wool can be used. It is important to wear gloves when cleaning car batteries, since the electrolytic solution is partly sulfuric acid and not for the faint-of-heart.

Under-hood heat

Under-hood heat can reduce the life of car batteries. Hot weather can damage the internal cells and evaporate the battery fluid, reducing its life. Fortunately, most car manufacturers install a thin insulation shield around the battery, which can be purchased online. You can also protect your battery by keeping it in good condition and charging it properly. Battery terminals should also be securely fastened without overtightening them.


One of the most important steps in maintenance is to check the electrolyte level and specific gravity of the battery. The electrolyte is a mixture of sulfuric acid and water and should cover the lead plates in each cell. If the electrolyte remains too low, it can corrode the lead plates inside the battery and cause problems. The electrolyte level should be around 0.5 percent of the battery’s capacity.

Structural failure

The ageing process of a car battery is one of the most common reasons for its premature failure. During normal recharging, electrolyte tends to concentrate on the bottom half of the cell, leaving the top half of the cell with low acid levels. Stratification is particularly common when the battery is low in charge – usually below 80%. This can also happen if the battery is being used to run an electric heater or running short distances. When this happens, the battery will lose its ability to take a charge and eventually fail.

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