Cold Weather and Car Batteries

Winter is coming.  While we’ve woken up to a few light frosts this month, last night’s temperature got down around 25 in many areas—cold enough to freeze hose spigots and potentially cause “no-start” issues in some cars.  Unlike our friends and family in the Northeast and Midwest, we’re used to fairly mild winters on average and therefore are less proactive with winter car maintenance.

So, why do batteries seem to suddenly fail in the cold?  It’s not because electricity doesn’t work in the cold, electricity conducts regardless of temperature.  But the fluid that conducts the electrical charge in car batteries is sensitive to temperature, particularly as it gets older.

A car battery contains 6 smaller batteries that are lined up, each compartment provides part of the charge needed to start your car.  If one of the compartments is weak (due to the chemical reactant being old), the other 5 compartments don’t add up to enough charge. A battery loses 50% of its cranking amperage below 32 degrees. If a battery is weak and only putting out 400 cranking amps then when temps are bellow freezing the battery will only have 200 cranking amps, not nearly enough amperage to turn over a car engine.

So if your car or truck is slow to turn over even at cool temps, there’s a good chance that the battery will fail when it’s really cold.  If you have any questions, stop by and we can test your battery’s cold cranking amps and let you know if you need a new battery.  It’ll take 10 minutes and could save you an unpleasant morning with a dead car or truck later this winter!


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