Rick's Free Auto Repair Advice

The 6 most common symptoms of a dead car battery

Learn the 6 most common symptoms of a dead car battery

There are several symptoms of a dead car battery; from a clicking noise when you turn the key to slow cranking or no cranking at all. I’ll cover all of them and which symptoms don’t indicate a dead battery

1) Rapid clicking when you turn the key is one of the top symptoms of a dead car battery

If you turn the key and hear rapid clicking, that means the starter motor is getting power, just not enough to fully engage the starter drive and crank the engine. Listen to this sound. If your car sounds like this, then start by cleaning the connections.

Remove the battery terminals and clean them and the posts with a wire brush. Then reconnect and try starting the engine. If it started, then the corrosion was the problem.

Dash lights coming on doesn’t mean your battery is charged enough to crank your engine

If you turn the key and your dash lights come on, that does not mean the car battery is good. Why? Because it takes very little power to light up your dash lights. In many cases, it only uses a few amps. But starting your engine requires a minimum of 100 amps.

2) You hear a single click when you try to start your car

This is one of the common symptoms of a dead car battery. The single click means the battery has enough power to operate the solenoid, but not enough power to run the starter motor. In some cases, however, it can be a sign of a dead starter. So always get the battery tested

3) No clicking and no dome light

A dead battery may not have enough power to produce any noise when turning the key

4) Slow cranking

5) Flunks a battery test

Modern battery testers are very accurate. Yet I’m still amazed a flunked battery test is one of the symptoms of a dead car batteryat the number of people who take their battery to the auto parts store, have it tested, and then don’t believe the results. It’s usually because they think that if there’s voltage, it must be good. Not true. A battery can show voltage or every turn on your dash lights, but that doesn’t mean it can produce enough amps to crank your engine at the proper speed.

5) Swollen battery case

In normal conditions, a fully charged car battery can’t freeze. However, a severely discharged battery can freeze in cold weather. When it does, the sides and top bulge out. So a bulged battery is a dead one

swollen battery case examples

Swollen battery caused by freezing

6) Leaking

The acid in the battery should stay in the battery. If any leaks out, replace the battery.

Checking your battery with voltmeter only tells you its state of charge, not its state of health.

Use a voltmeter to check your car battery voltage. A fully charged battery should read 12.6 volts and 12.2 volts represents a battery that’s 75% discharged. If your battery reads 12.6, that’s not the end of testing. Battery voltage only tells you the battery’s State of Charge (SOC). It does not tell you the battery’s State of Health (SOH).

Use a battery tester to determine the car battery state of health

To determine SOH, you’ll need a modern digital battery tester that performs a simulated load test along with a conductance/resistance test. These tests determine the condition of the lead plates and bus connections inside the battery. A battery can pass the SOC test but fail the SOH test. You should replace a battery that fails the SOH test because it’s an indication of impending failure.

© 2012 Rick Muscoplat

Posted on by Rick Muscoplat

Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN