Category Archives: car battery fail in winter

Why do car batteries die in the cold weather?

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woman trying to repair broken down carWinter in Wisconsin always comes with surprises, like the snow storm that the weather man didn’t predict or an icy spot on the road. What it shouldn’t come with is a dead battery and a surprise jump (or worse a dead battery that can’t be jumped).

While you can’t always avoid the need for jumper cables (unfortunately, some batteries fail unexpectedly), it can help to know why car batteries seem to fail more when the temperatures drop.

Why do batteries fail during winter?

Surprisingly, summer heat is actually harder on car batteries. Batteries consist of cells surrounded by an electrolyte solution (more information on how batters are made in this video). Hot weather can hasten corrosion and cause the solution to evaporate in the battery. This damage weakens the battery, which car owners often don’t notice until the temperature drops. When the weather gets colder, the fluids in a car become like molasses. It’s harder for the battery to start up the sludgy fluid in winter—leaving car owners out in the cold with a weak battery that needs to be jumped.

What is the right way to jump a battery?

  1. Park another car near the front of the car with the dead battery. Turn the car off, and use the parking brake if necessary to secure the car.
  2. BE CAREFUL! Electrical systems can cause situations where someone could get hurt. Be very careful when jumping a battery.
  3. Find the positive and negative terminal on the battery. A plus sign is positive and a minus sign is negative.
  4. Clamp the positive cable to the positive terminal on the dead battery.
  5. Clamp the other end of the positive cable to positive terminal on the live battery.
  6. Do the same with the negative terminal on the dead battery.
  7. Clamp the other end of the negative clamp to a non-moving metal part of the engine. Do not reach into any areas with moving belts or parts.
  8. Start up the car that runs. Let the car run for a few minutes.
  9. Try to start the car with the weak battery.
  10. Remove the jumper cables.
  11. Get your battery checked and replaced if necessary.

If a battery needs to be jumped often, contact a mechanic to get the battery tested. A weak battery should be replaced.

How can I tell if my battery is going to fail?

As mentioned before, a dead battery cannot always be foreseen. In most instances, however, there are signs that a battery needs to be replaced: