How Temperature Affects Your Car Battery

Jan 22, 2016 by Darren (Driver Weekly)

Car batteries give the best performance at a temperature range of 20°C to 30°C. The life and performance of the battery are significantly impacted by extreme fluctuations in temperature with heat being just as harmful as cold.

Basics of the car battery

A car battery (or lead acid battery) is an electrochemical device that includes several basic elements such as the housing to hold the various elements, electrolyte solution that helps to supply sulfate and water to promote the electrochemical reaction which gives the battery its power and a series of electrodes to help gather the electrical charge.

Your car battery is based on a series of cells which contain negative (lead dioxide) and positive (pure lead) electrodes. By combining these metal types in liquid like sulfuric acid, it is possible to create an electrochemical reaction which is possible to measure in volts. This electrical input has the ability to provide a sufficient charge to turn over the engine as well as other ancillary components like the fans, lights, and radios. 

How temperature takes its toll

Temperature can play a critical role in the operation of the car battery because it runs based on chemical reaction. The preferred operating temperature of a car battery to give optimum performance is in the region of 26.7 C (or 80 F). Prolonged exposure to heat causes the battery’s water to evaporate, which causes damage to the inner components of the battery. One component that is easily damaged by heat is the voltage indicator. Should this part fail, the battery is no longer able to charge and operate at the optimum rate, which also leads to a loss of electrolytes. Once the electrolytes are lost, this leads to the complete failure of the battery. While chemical activity is generally accelerated by heat, excess heat isn’t appreciated by the battery because it speeds up cell corrosion which will shorten the lifespan of the battery. The most noticeable damage is caused to batteries that repeatedly experience high temperatures without having the benefit of being able to cool down. Similar to heat, the cold temperature can have an adverse impact on the car battery which leads to a slowdown in its chemical reaction. This means the battery is less efficient and unable to provide the desired power to run and start the engine and related components. A car battery can be rated in cold cranking amperage (CCA) which helps to identify the battery current delivered for a 30-second interval at a temperature of -18 C without loss of performance. For cold weather driving, a battery with a high CCA rating is sure to give the most desirable operating performance.

Batteries can freeze

A lead-acid battery kept fully charged has the potential to survive in cold temperatures in the region of -50 C, but the poorly maintained and charged battery can easily freeze at just -1 C. Once the liquid in the car battery starts to freeze it will expand which results in permanent damage to the cells which cannot be repaired.

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