How To Test A Car Battery For A Dead Cell

A battery is composed of a series of cells each of which produces a certain amount of voltage. A dead cell in a battery will produce no voltage and will prevent the battery from starting the car. To test for a dead cell in a battery you will need a voltmeter.

First make sure that the battery is properly charged. A dead cell will not be able to hold a charge so it is important to make sure that the battery is fully charged before testing.

Next disconnect the negative terminal of the battery. This will prevent the voltmeter from reading the voltage of the battery as a whole and will allow you to test each cell individually.

Attach the voltmeter to the positive terminal of the first cell in the battery. The voltmeter should read 12 volts. If it does not then that cell is dead. Repeat this process for each cell in the battery.

If you find that one or more cells in the battery are dead then the battery will need to be replaced.

What is a common cause of batteries dying?

Answer: Batteries can die from overcharging sulfation corrosion or simply being old.

What is sulfation?

Answer: Sulfation is when lead sulfate crystals build up on a battery’s lead plates.

This can happen when a battery is left discharged for too long.

How can you tell if a battery is sulfated?

Answer: If a battery won’t take a charge it may be sulfated.

You can also check for sulfation by doing a load test.

What is a load test?

Answer: A load test is when you put a load on the battery to see how well it performs.

This can be done with a load tester or by starting the car with a voltmeter attached to the battery.

What is a voltmeter?

Answer: A voltmeter is a device that measures voltage.

How do you attach a voltmeter to a battery?

Answer: You can attach a voltmeter to a battery by connecting the positive lead of the voltmeter to the positive terminal of the battery and the negative lead of the voltmeter to the negative terminal of the battery.

What should you do if your battery tests bad?

Answer: If your battery tests bad you should replace it.

Can a battery be repaired?

Answer: In some cases batteries can be repaired.

This usually involves adding water to the cells or replacing damaged cells.

How do you add water to a battery?

Answer: You can add water to a battery by removing the caps from the cells and adding distilled water until the cells are full.

How do you know when a cell is full?

Answer: When adding water to a cell stop when the water level reaches the bottom of the fill tube.

What is the danger of overfilling a cell?

Answer: The danger of overfilling a cell is that the battery can explode.

How often should you check the water level in a battery?

Answer: You should check the water level in a battery at least once a month.

What are the signs of a battery starting to fail?

Answer: The signs of a battery starting to fail are dim headlights slow cranking and the check engine light coming on.

What is the first thing you should do if you think your battery is failing?

Answer: The first thing you should do if you think your battery is failing is to have it tested.

Where can you have your battery tested?

Answer: You can have your battery tested at most auto parts stores.

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