You cross your fingers and whisper a prayer under misty breath as you turn the key in a cold parking lot. It started earlier, but you could hear the car battery straining to turn over even then. Now your vehicle has been sitting in the frigid cold all day and there’s a chance you could be digging for change to catch the bus home.
Situations like this offer a stark reminder of how much extreme temperatures can affect the performance of your car battery. To gain a better understanding of why this happens, it’s important to learn how batteries work.
Car Battery Basics
A car battery is an electrochemical device that consists of three basic components:
- Electrodes that collect an electrical charge
- Electrolyte solution that supplies water and sulfate for the electrochemical reaction to occur
- Battery case to house these components
Your battery, also known as a lead acid battery, is comprised of a series of cells containing positive (pure lead) and negative (lead dioxide) electrodes. When these different metals are placed in a solution of sulfuric acid, a reaction occurs which causes a potential difference between the electrodes, which is measured in volts. The current this provides is used by your vehicles ignition system to turn over the engine and power ancillary devices such as radios, lights and fans.
Temperature Can Take a Toll
It’s getting hot in here: Heat typically accelerates chemical activity, but higher temperatures also speed up internal corrosion within the cells and reduce the life of the battery. This is particularly true of batteries that repeatedly reach high internal temperatures, and once capacity has been damaged by heat, it can’t be restored.
Cold bogs batteries down: Just as heat speeds up chemical reactions, cold temperatures slow them down. That’s why a battery can become sluggish in winter, even though its state of charge may remain unchanged.
At colder temperatures, the battery’s ability to provide sufficient power to start and run a vehicle is diminished. That’s why automotive batteries are rated in CCA (Cold-Cranking Amperage). This is the amount of current a battery can deliver for 30 seconds at -18 C without dropping to a specified cutoff voltage. Obviously, the higher the CCA, the better the battery will perform in adverse conditions.
Batteries can freeze: A fully charged lead-acid battery can survive up to –50 C, but a battery with a low state of charge can freeze at –1 C. When the water in a battery freezes it expands and can cause irreparable damage to the cells.
If your vehicle is struggling to turn over, read: How Can You Tell if You Need a New Battery?
Are extreme temperatures taking a toll on your car battery? Come by one of our Kal Tire locations for a free battery test. We stock a full range of batteries that’ll deliver the cold-cranking amps your vehicle needs to handle the toughest Canadian climates.