How to Start a Car With a Frozen Battery

by Hans Fredrick
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dead battery image by Katrina Miller from

Cold winter temperatures are hard on a car's battery. As the weather drops, so does the battery's ability to create the power that is necessary to turn the engine over. Cold weather can often make a battery die. Then, the battery will need to be boosted or charged in order to start the engine. However, in extremely cold temperatures, a battery may actually freeze rather than simply drain and die due to the cold. It is important to recognize the difference, and to learn how to deal with an actually frozen battery.

Step 1

Find out if the battery is actually frozen, or merely dead. Look at the car battery. If the fluid inside the battery is still liquid, then your battery is not frozen. You can charge or boost it instead. If it is frozen, you need to thaw it before it can be used. Never attempt to boost a frozen battery, as it could explode. Never attempt to boost a battery if the case has cracked due to cold either.

Step 2

Plug in the car if your car is equipped with a block heater. Most cars in cold weather regions should be equipped with these. Plug the car in for at least two to three hours, and check the battery. If it is not starting to thaw out by then, the block heater alone is likely to prove ineffective.

Step 3

Remove the frozen battery from the car. Remove the battery cover, detach the battery cables and carefully pull the battery out. Put the battery in a warm garage and allow the battery to thaw. If you need to use your car immediately and have a spare battery, you can install it, and see if the car will start. Not all cold weather starting problems are restricted to the battery. If the weather is cold enough to freeze a battery, your car still may not start.

Step 4

Tow the vehicle to a heated area if you do not want to remove the battery. If you are parked in the driveway and have an available garage space, push the car inside the garage, and turn up the heat until the battery has thawed.

Step 5

Test the frozen battery after it has thawed out, and charge it. Most batteries which have frozen will need to be charged. Inspect the battery, and ensure that it is not cracked or leaking before you attempt to charge it. Also, ensure that the battery is completely thawed before you hook it up to a charger.

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