Battery Warning Light

Battery Warning Light

Battery Warning Light-All You Need To Know

Battery warning light

What does it mean when the battery warning light illuminates on your car’s dashboard, while the engine is running?

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It basically means the alternator is not charging the battery.

Some cars have a volt gauge and a battery warning light, others just a light to warn of malfunction.

Let’s start at the beginning.

Main electrcal components in a car

Electrical System Main Components

In the above illustration, we see the basic components making up a car’s electrical system, in relation to the battery warning light, we will consider the Battery(far left) and Alternator(far right)

The battery supplies the car’s system with electricity, but the alternator is responsible for keeping the battery charged(filled with electricity)

Cars runs mainly on a 12-volt system, but when being charged constantly the voltage goes up to approx, 14 volts, compensating for a drop in voltage due to long cabling and other various factors.

Connected between the Alternator and the Battery is a warning light in the shape of a battery icon(top in the illustration-on the dashboard), this warning light illuminates when the ignition is turned on, to indicate the circuit is functioning.

When the car is started the battery warning light goes out immediately, indicating the charging system is working correctly.

When the battery warning light illuminates while the engine is running, it indicates the battery is not being charged, this is a dire situation.

After the battery depletes, the car will stop due to inadequate or no electric power and cannot be started again as the battery has no more power/voltage.

A typical battery warning light


Common Causes

  • Broken Fan Belt
  • Malfunctioning Alternator(not charging the battery)
  • Short Circuit in the car’s electrical system.
  • Bad or no earth connection
  • Faulty Battery(not holding the charge)

Until Next Time "Safe Motoring"

Gary De La Cruz

I have been 30+ years in the motor industry, still hands on, and have great passion for my chosen profession, I learn new things each day and believe that "if you enjoy your work, you never have to work a day in your life"I believe in honesty, integrity and helping where help is needed.

This Post Has 2 Comments

  1. Clara buttler

    Battery provides electrical energy required by different types of electrical appliances. However, weaker or older battery couldn’t do so in an effective way. So, the condition of the battery needs to be inspected at a regular interval by conducting volt test and replacement of weaker battery is really essential to ensure continuous power supply to different types of electrical appliances used in the vehicle for various purpose. Apart from this, the condition of alternator should be inspected at a regular interval to evaluate it’s condition.

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