A snowed under sedan.

Cold Weather Car Battery Tips and Tricks

Car batteries must work harder in cold weather to turn your engine. The lower the ambient temperature, the greater the internal resistance along with a corresponding reduction in battery capacity. Thus, at zero degrees Fahrenheit, your car’s battery may operate at only half of its charging capacity, possibly rendering your car undriveable.

The following four cold weather car battery tips and tricks may help you avoid an emergency call to roadside assistance this winter:

1. Turn Each Power Load Off

When you start your car, energy from the battery supplies ignition to start the motor. At the same time, power is sent to various systems that may not have been turned off when you last drove the car. Just like that, extra power feeding the audio system, navigation, headlamps, wiper blades, heated seats and climate control system may overwhelm your battery on a cold day. Therefore, make it a habit to switch off each power draining load before turning off your car.

A corrosive battery can render your vehicle inoperable.2. Park Your Car in a Garage

You can’t do anything about the weather, but you can mitigate its impact on your vehicle. A battery providing 100 percent capacity during the summer will usually supply half that capacity when temperatures approach zero degrees Fahrenheit explains Battery University. That means an older, less effective battery will have an even lower capacity than a new battery.

If possible, park your car in an enclosed structure, such as a garage. Heated or not, a garage provides protection from energy sapping winds and should allow your car to start on the coldest mornings.

Note that you should never idle your car in the garage as toxic fumes may enter your house.

3. Clean the Car Battery

Your battery may be at full capacity, but if corrosion is present, then it may not be able to start your car. To avoid this pitfall, you should be proactive and perform some maintenance on your battery.

First, take a wire brush and clean around each cable and terminal. Second, remove the negative and then the positive cable. Third, mix a solution of one cup water with two teaspoons baking soda and apply to the dust-like corrosion. Fourth, using a rag, wipe down the battery, including the posts. Fifth, spray corrosion protection on each post. Lastly, reconnect each clamp, starting with the positive one before moving to the negative connection point. Use a pair of pliers or a wrench, as needed, and always double check the connection points are secure.

4. Test It Out

If your battery is older, especially if it is at least three-years old, it should be tested to ensure it has sufficient capacity. A digital multimeter will accomplish that task. First, set the range on the DC voltage scale to 20V, then insert the positive or red test lead of the multimeter into the terminal denoted by a “V” for voltage. Second, insert the negative or the black test lead into the terminal marked “COM” for common. Third, activate the multimeter, then connect the open end of the positive lead to the battery’s positive terminal, then do the same with the black lead. Fourth, observe the voltage number on the multimeter screen. If the battery is fully charged, then it will read at least 12.65 volts. If it reads 12.4 to 12.6 volts, you may need to recharge it for up to 12 hours. With a reading of 12.3 volts or lower, your car battery should be replaced.

Check out all the electrical system products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For additional information on cold weather car battery care, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Flickr

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Matthew C. Keegan

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