Alternator Vs. Battery


Is your car having problems? Won’t it start when you try to turn on the engine? Well, the problem sometimes lies between the alternator and the battery. Many times, people think when their cars get faulty, it is because it lacked proper maintenance. While this could be true, it could also be that some parts are due for replacements.

Knowing what is wrong with your car can be quite a challenge – you are not sure if you are to replace the battery or the alternator, as it won’t start. However, certain things would help you discover where the problem is; all you need to do is find them. In essence, the purpose of this Alternator Vs. Battery article is so that you won’t have to misdiagnose anymore.


How to Know the Problem: Alternator or Battery?

Things that are peculiar to these car parts when they are damaged are often used to diagnose the problem. It gets easier knowing the symptoms of a bad battery and a bad alternator.

A Bad Battery

It doesn’t take so long to know a failing battery. It often starts from maintaining it, i.e., how you constantly check the water levels and do what is necessary. If you also discover that when you crank the engine, it acts slow or sluggish, you might be facing this problem. Other signs include difficulty starting the car on cold mornings or no lights and sound when the engine is ignited.

An observable symptom of a low battery is that the terminals are corroded, meaning they are damaged. If you try to find a way around it by jumpstarting the car with another battery and it works, you don’t need further shreds of evidence that you have got a battery issue.

Sometimes, what causes a dead or bad battery is the alternator; so, you might want to look out for both of them. In other cases, electrical draws or connections, such as sound systems, alarms, auxiliary lights, fuses, etc., could run the battery out of power.

A Bad Alternator

Some of the bad alternator symptoms are quite visible; you see them most times but pay no attention to them. An alternator doesn’t get damaged at once; it takes time. You could have trouble starting the car – it doesn’t start at first, and then it does later. Others include dimming lights and poor output of the stereo system. With all of these, you can only conclude that your alternator is bad.

For a more coherent approach to know whether the alternator is bad, try to rev the engine with a few things in motion. For instance, a whine or fuzzy sound is produced when you switch on the AM radio and then rev the engine. It is also a sign that the alternator is not in great shape.

Lastly, some cars have an inbuilt battery indicator light that runs fast diagnostics. If it shows that a car’s charging system is faulty, the best guess is that the alternator has an issue. As you know it, an alternator charges a battery.

What Does A Battery Do?

A Car Battery is a rechargeable battery that is used to start a car. It is the Power Reserve that makes every other thing in a car function. Ideally, it uses its Lead-Acid constituents to provide electric current to the motor that ultimately converts it to chemicals for combustion to power a car.

Usually, batteries do not last so long; they only provide good current over a short time. Afterward, they are due for replacement. However, you need to maintain a car battery so that life wouldn’t run out so fast. One of the ways to do that is adding water to the battery – not too much and not too little.

When the need for replacement comes, you will observe the battery acting strangely; sometimes, it could confuse you. The next thing you should do is call for skilled professionals (mechanics) to change the battery.

What Does An Alternator Do?

It wouldn’t be so difficult to say that many batteries get bad because the alternator is. It is an electric generator that charges a car battery. It is also a useful component to power the electrical systems of a car with a running engine. The history dates back to the 60s, as they became alternatives to DC dynamo generators.

Before you change a bad battery, make sure to run a diagnostic test on the alternator for safety. It would surprise you to know that a bad alternator can ruin a perfectly healthy battery, as it maintains its voltage.

How Much Does an Alternator Cost?

Alternators are quite expensive, depending on the model of the car you are driving. The cost of hiring a professional to do the job is another, which is most advisable. However, if you can handle it yourself, then all you might need to spend on is getting an alternator.

On the contrary, you could go for fairly-used alternators if you cannot afford a new one. The con about doing this is that: you may not have to use it for so long before replacing again. Local junkyards and Parts recyclers should have deals available.

If it is Not the Battery or Alternator, Then What?

If your car doesn’t start even with the battery and alternator in good form, then you may have to visit a mechanic. It could be that your connections are wrong, and they need a little adjustment. However, when you start the engine, the car’s failed response is mostly due to its battery or alternator quality – no car runs with a low battery and bad alternator.


Many car owners often find articles like this useful, as it targets many of the issues faced with car maintenance‘. It is certainly not today that it has been quite the challenge to know what is faulty in a car; however, this Alternator Vs. Battery article provides an insight into the common signs and symptoms. Overall, invest in your car and enjoy a smooth driving experience.