There is a mutual relationship between an alternator and a battery. A few tips below can help you find the exact reason behind your car electrical systems not running properly.

The battery and the alternator work in cohesion to power your vehicle’s essential components, including the engine, air conditioner and entertainment systems. When the engine gets started, the alternator jumps into the scene and begin charging the battery. It keeps doing that until the engine is turned off.

When a car battery is bad, you will have a problem cranking the engine, and similarly, if the alternator is in bad shape, the vehicle can run only for a small period. If the car is not starting, then either the battery or the alternator is going haywire. It is necessary to know the difference between a bad battery and a bad alternator so that you have enough knowledge to get your car started without causing additional problems.

It is not that easy to figure out the exact problem your car is facing. But, a few tips can help you find whether it is the battery or the alternator that’s causing the problem.

Checking the battery

Some of the things you can check in the battery are as follows:

Battery gauge – Dead battery not starting is a common problem in cold weather conditions. One should look at the battery gauge on the dashboard if it is sending a charge when you turn off the car. If you see a dim or flickering light, then it indicates that something else is consuming the battery power.

Common connections

The next step you can take is to check the common connections such as windshield wipers, automatic window openers and brake lights. Turn them off and try to start the car again.

Check for corrosion

Check the battery for any corrosion and clean it off and then see if the battery shows any sign of life.

Battery voltage

The next thing you can do is to check the voltage of the battery using a voltmeter. Normally, it should be about 12.6 volts when the car is off. Turn the engine on and check the battery with the voltmeter again. If it reads between 14-15 volts, then the battery is fine. But if it is less than 13 volts or more than 15 volts, then the voltage regulator, the wiring or the alternator might be faulty.

If the battery is unable to store charge even if all the electrical components and accessories are turned off, then you must check other systems that are dependent on the battery for running the car.

Checking the alternator

Sometimes your car starts but can get stalled in the middle, which means the battery is not getting charged with the alternator.

First step

A simple test, to begin with, is by starting your car and then unplugging all the positive connections attached to the battery. If the car comes to standstill, most likely, the alternator has an issue.

Second step

Another thing you can check is whether the interior lights of the car is working or not since the alternator charges the battery. Start the car, and turn on the interior light. If you see the lights starting brightly but slowly fading, then it shows that there could be a fault with the alternator as it cannot keep the charge while the car is running.

Third step

The next thing you can check is if the car lights are bright while you accelerate but start to go down when you decelerate. It demonstrates that something is going on with the alternator.