Battery Failure

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Automotive battery indicator light

Years ago, vehicles were equipped with carburetors and required a longer cranking time to start. In many instances this longer cranking time would reveal a weak battery. You could actually hear the cranking power reduced especially in cold weather. When fuel-injected engines became the norm this was not as evident due to the fact that the vehicle starts up quicker.

A sudden change in temperature usually takes a weak battery out. That’s why the day before your vehicle may have started fine, with no warning of a problem. Then an extreme change in the weather (hot or cold) causes the weak battery to die, seemingly without a warning.

Why do batteries fail?
It’s unusual for a battery to malfunction because of a defect, driving habits are the usual cause. Using a lot of vehicle accessories and driving short distances prevents the battery from fully charging. Extended idling with heavy accessory use or driving a short distance only once a week can also reduce battery performance.

Typical electrical loads

(example from General Motors)

When the battery does not have have an opportunity to charge fully, acid stratification occurs. The electrolyte (battery acid) in a stratified battery concentrates on the bottom. It is similar to the way sugar granules collect on the bottom of a cup of coffee before it is stirred. Batteries tend to stratify if kept at low charge (below 80%) and don’t get the opportunity to receive a full charge. For example, short distance driving while running windshield wipers and electric heaters contributes to acid stratification. Acid stratification reduces the overall performance and life of the battery.

How to protect the battery
Check your battery every two years and keep the connections clean. Also clean the area around the battery hold down. Usually if a battery is super corroded the terminals leads are no longer airtight. If you clean your battery terminals and cables and the corrosion returns, replace the battery. If your battery is four years old and corroded, replace the battery.

Battery terminal corrosion

Batteries can cause all kinds of crazy problems; the vehicle’s electrical system has to be 100%. I have seen people replace parts on vehicles when the only thing wrong was a weak battery.

Just recently I checked a friend’s car and found a dead battery. I explained the battery read 12.5v but would not start the vehicle. He came back and told us the battery was okay. I asked the gentleman if he load tested it. He had not, but when he did he came back with a new battery.

Batteries can be difficult to diagnose, if your battery is more than three years old, my suggestion is to replace it. If you are seeing excessive corrosion and have had problems don’t fool around with an old battery. Have it checked out.

Battery Basics

Typical automotive batteries are made of five basic components:

  1. A plastic container.
  2. Positive and negative internal plates made of lead.
  3. Plate separators made of porous synthetic material.
  4. Electrolyte, a dilute solution of sulfuric acid and water, better known as battery acid.
  5. Lead terminals, the connection point between the battery and whatever it powers.

Battery construction

Battery cutaway images courtesy of Battery Council International

Battery cutaway images courtesy of Battery Council International

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4 responses to “Battery Failure”

  1. Leah Glauto says:

    It’s interesting to read about the history and how far the automotive industry has evolved since it started. Batteries have played a great part in that.

  2. Cheryl Smith says:

    My grandfather’s battery seems to be dead all the time. I always have to help jumpstart it. I didn’t know it should be replaced every three years. If it sits idle for a long time, could this be the problem?

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