An alternator belongs to a class of electric generators, used to charge car batteries. They’ll also power a car’s electrical system when you’ve turned on its accessories.
Without a working alternator, your battery would slowly drain any time you were using the car.
But do all cars, even modern cars, use alternators?
All modern vehicles need alternators because of their electrical systems. They’re the only devices capable of supplying a steady charge, even at idle speeds. Most alternators last around 100,000 miles if you get them when they’re brand-new.
Prior to 1960, most cars had a DC generator. The introduction of silicon rectifiers changed how they were made around that time.
The first alternators built using modern designs were made during WWII. They spread to other applications following the war, ones with high power demand.
Chrysler produced the first consumer vehicle with a modern alternator, the Valiant. It first hit consumer markets in 1960, followed closely by models from Ford and GM.
Modern cars replaced dynamos with alternators because of their advantages.
Using an alternator to generate power doesn’t weigh down the car as much. Alternators aren’t as fragile as dynamos, either.
If you bought a car built after 1960, you’ll need one of them to keep its battery charged.
Anything older than that would mean you’d have to get a dynamo, instead.
The biggest difference between modern alternators and old ones is their power output.
It wasn’t uncommon to find them with amperages under 30 amps.
Modern alternators rarely produce fewer than 50 amps, and many of them produce 70 amps or more.
Commercial vehicles have alternators that produce up to 300 amps.
You can find commercial alternators capable of generating more, depending on the application. The more electric a vehicle needs, the more powerful its alternator will be.
What Does an Alternator Do?
A typical alternator has two windings.
One of them is called the stator, and it sits on the outside. The rotor winding rotates around the interior of the device.
Your alternator receives a voltage through its regulator. Once you’ve turned on the car, the engine causes the serpentine belt to turn the rotor winding. As it rotates, an electrical current moves through it.
This creates a magnetic field, surrounding the rotor winding. As a result, an AC current propagates in the stationary winding.
Diodes placed along the alternator convert AC current into DC. That’s what’s used to power the vehicle’s electrical system.
Your alternator controls how much voltage exits by using a voltage regulator. This only allows so much current to pass through, protecting your electronics.
Modern automobiles still use the same basic principles to build their alternators.
However, they’ve updated their designs to make them more compact. This also has the added bonus of reducing their operating temperatures.
Improving its cooling has made it possible to generate more power while using a smaller one. So, modern alternators tend to be much smaller than what you’d see years ago.
Many of them have slots, cut into the side, acting as vents. Some manufacturers even install fans in them to make sure they’re cooled if you turn on the car.
They’ve opened up the alternator’s casing to expose its windings, improving heat transfer. Another way they’ve upgraded its design is by packing the cores tightly. That’s improved the design’s magnetic efficiency and reduced their effective size.
You can even get an alternator that’s water-cooled. They’re capable of powering large devices without overheating.
How to Tell If You Need a New Alternator
Your car isn’t going to stay on for long if its alternator stops working. Most of the time, modern cars have to use electricity to keep their engines running.
A dead alternator is usually an easy fix, but you’ve got to realize it’s the problem. Keep an eye out for the following signs if you suspect your alternator has stopped working.
One of the simplest ways to check is by looking at the dashboard, behind the steering wheel. That’s where most cars show you any indicators that you can look up in the manual.
Most of them use a symbol that looks like a battery with a line going through it. If you see that, it’s telling you there’s something wrong with the alternator.
You can also go to an auto parts store and buy a voltmeter to check the alternator yourself. Once you’ve bought one of them, you can use it to test the alternator’s current.
You may need to get a battery charger so that you can turn on the car, though. Asking a friend to jumpstart the engine is also a possibility.
Test the battery’s voltage with the engine off. It should be somewhere around 12 to 14 V if the battery is in good condition.
Now, you’ll have to turn on the engine and test the battery again.
Once you’ve turned the engine on, you should notice that its voltage jumps. Most of the time, it’ll read 14 V or more if the engine is running.
If your voltage doesn’t increase, then something is wrong with the alternator.
You can also pay attention to your car’s accessories to see if the alternator is failing. If the interior lights seem like they’re flickering, it could be the alternator.
Has your car battery been dying if you leave the car alone, lately? That’s a really common sign that you’ve got a bad alternator.
Replacing it should prevent the battery from going dead as often. That’s going to increase its reliability, making it crank with ease.
What Does a New Alternator Cost?
You’ll need to consider two costs if you have to replace your car’s alternator. The cost of the part is usually not too expensive. But, you can double the final price after you’ve calculated labor costs.
You can expect a new alternator to cost between $500 and $1,000 if you have a modern car.
That’s including the cost of the parts and labor. Replacing an alternator isn’t too complicated if you know how to work on cars.
Doing it yourself would be a great way to save on labor expenses. A prefabricated alternator only costs $150 if you’re driving an inexpensive car. So, replacing one of them isn’t always a high ticket repair.
Still, if you’ve never worked on a car, hiring someone else is a better idea. You won’t be able to drive unless the alternator has been installed properly.
Look at a few online videos to get an idea of how difficult it would be to tackle this project without any help.
If you feel like it’s doable, you can save a ton by taking care of it yourself.
Just make sure you’re paying attention to the way its serpentine belt connects to all the rollers. They’re put on them in a particular way that you’ve got to replicate. Otherwise, it’s not going to spin the alternator winding’s, rendering them ineffective.