Let’s discus how to buy the right alternator for your vehicle. First things first. It needs to fit. A different year or a different engine may require a different alternator, even on the same make and model.
Another consideration is the brand. Reputable brands—such as AC Delco, Bosch, DB Electrical, and Remi—ensure you are getting an alternator that lasts. eBay has a vast selection of high-quality brands to consider.
One final aspect to decide if you want a new, used, or rebuilt alternator. Read on.
Types of Alternators
A Balmar marine alternator kit.
The alternator is the heart of your vehicle’s electrical system. It turns mechanical energy from your engine into electrical energy to charge your battery and run your car’s electronics. You need an automotive-specific alternator.
Automotive alternators often use a brushless configuration with an internal regulator. They generate AC power that is converted into DC power by the rectifier. The internal regulator ensures a consistent voltage for the electrical system’s power supply while keeping the battery charged.
Boats use alternators, too, but they are different from the ones used in cars. Marine alternators are very similar in design, except that they are created to withstand the salt-water combination, and they have further protections from sparking that could start a fire. Some larger boats and yachts have two or more alternators to supply enough power.
How do you find an alternator that fits your car?
It’s important that the alternator you choose fits your car. With the
eBay Parts Finder
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, you don’t have to worry about compatibility. Start on eBay's page for car and truck alternators and generators. Then, filter results by your car’s year, make, and model to find all the options that work on your vehicle.
Again, be mindful to plug in the correct year, make, model, trim, and engine of your vehicle to ensure you get the correct part. You can filter by brand and warranty to help ensure you get a quality product.
How Much an Alternator Should Cost
When buying a rebuilt alternator, stick with a top brand.
Alternator prices
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depend on the vehicle you drive and the condition of the alternator. For example, brand-new alternators with a warranty commonly cost between $200 and $400.
A similar rebuilt alternator may only be about $100. Keep this in mind: A rebuilt alternator might not last as long as a brand-new unit.
There’s also the option to purchase an alternator rebuild kit for around $50. These require more work. You will need to replace the internal components of the alternator, including the resistors, rectifiers, bearings, diodes, and brushes to make it like new again. This was a common option in the past when alternators were more expensive. Most people now prefer to replace the whole alternator as a unit to save time.
New vs. Rebuilt vs. Used Alternators
While a used alternator can save a few bucks in the short term, buying a new or rebuilt unit is usually the safest bet.
A new alternator with a warranty is the best option. This is the most reliable option, although it will cost the most upfront.
Rebuilt alternators have been refurbished to meet original equipment specifications and may include a warranty. The price is typically less than a new alternator but more than a used variant.
A used alternator saves money on the initial purchase price, but it could cost you more in the long run. Only buy from a reputable seller who offers a guarantee. There’s no way to be sure how long a used alternator will last.
What's the best alternator for car audio?
Buying an alternator for your car requires finding the right alternator to fit your year, make, and model. If you have a modified car, you may need to choose an aftermarket option that can handle any upgraded components.
When you upgrade to a high-end sound system, your vehicle requires more power than if you keep the equipment stock. There are higher electrical demands. Upgrading the alternator helps ensure the battery doesn’t die. Depending on the size of the sound system, you may need an alternator with between 150 and 250 amps. You also want a reliable brand, such as Mechman, Singer Alternators, or XS Power.
Does alternator amperage matter?
Alternators are based on the power output provided. This measurement is shown in amperage. Its higher rating shows the amps provided while driving at a higher rpm, possibly around 125 peak amps. During idle, output naturally drops, with many alternators listed around 40 amps. When replacing the alternator, you don’t want anything less than the original component. The owner’s manual should list the alternator specs. However, if you’ve added aftermarket electronics to the car, it wouldn’t hurt to get a better alternator.
Should you consider a three-wire alternator?
There are also one- and three-wire alternators. A single-wire design connects to the positive battery terminal and positive alternator terminal, requiring a certain rpm before the alternator can supply power. On the other hand, a three-wire alternator provides amperage after starting the engine, so it’s better for cars with increased power demands.
Most cars are designed with a three-wire design, but some enthusiasts switch to one wire to clean up the engine bay. There is not much cost difference between a one- and three-wire setup, so choose based on electrical needs and looks.
Parts Commonly Replaced When You Change Alternators
We recommend installing a new serpentine belt when replacing your alternator.
While
replacing the alternator
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, we always recommend inspecting the corresponding parts. Look carefully at these parts to ensure everything is working as it should. It will be easier to swap them out now while you are already working on the car:
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Serpentine belt (drive belt)
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Tensioner
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Idler pulleys
Use a voltmeter to differentiate whether a car battery or alternator has gone bad. Many people mistakenly only replace the battery when the alternator is the problem. However, if your car battery is old, you may want to replace it at the same time as the alternator. When a failing alternator supplies too much voltage to the battery, the alternator can wear out the battery.
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This article is meant to provide general guidance only. Automotive maintenance, repair, upgrade, and installation may depend on vehicle-specifics such as make and model. Always consult your owner's manual, repair guide for specific information for your particular vehicle and consider a licensed auto-care professional's help as well, particularly for advance repairs.