Alternator Buying Guide: Everything You Need to Know

What Is an Alternator and What Does It Do?

A car alternator isn’t just a part; it is the powerhouse of your vehicle’s electrical system. In majority of modern vehicles, a functional alternator is needed to charge the car battery, which supplies power to:

·       The battery

·       Lights and dashboard electronics

·       Radio, AC, and infotainment

·       Engine sensors and controls

If your alternator fails, your vehicle will eventually stall and here's a chance you'll be left stranded on the side of the road.

 

When do you need a new alternator?

Before buying a new alternator, we need to make sure it's the problem. Here are common symptoms of alternator failure:

·       Dashboard warning light (usually a battery symbol)

·       Dim or flickering headlights

·       Dead or weak battery (despite a new battery)

·       Grinding or whining noises coming from the alternator

·       Output voltage of alternator is lower or higher than average normal level 13.5–14.5 volts while the engine is running.

However, there are problems that look like alternator Issues but aren’t actually caused by the alternator., including 

• Faulty battery
• Loose or Corroded Battery Terminals
• Blown Fuses
• Slipping alternator belt
• Wiring Issues (especially ground connections)
• Faulty belt tensioner or water pump making grinding noises

We usually recommend seeking a professional diagnosis from a qualified auto electrician or mechanic.

 

Where to buy a new alternator?

There are several options for buying an alternator:

·      Auto parts stores

·      Genuine part dealers

·      Online retailers e.g eBay, Amazon, or like us

·      Directly through local mechanics

 

How to Choose the Right Alternator?

Most consumers often wonder how to choose the right alternator for their vehicle, because they have shopped around and encountered many different options, making a decision can be overwhelming sometimes. Here is a step-by-step guideline to help you choose the right part.

 

Compatibility

Usually, the simplest way is to provide the 17 digits VIN number or registration number to the retailers, they can use this information to check on their catalogue and source the right part. 

Providing only the year or model of the vehicle is not always sufficient. Some car makers, especially Nissan, BMW, and Mercedes, produce the same vehicle model in different countries, often using different parts depending on the production region. 

Our part specialist team has extensive experience and in-dept knowledge in identifying the correct part for your vehicle.

This image above shows the different alternators used in Thai built Nissan Navara D40 vs Spain built Nissan Navara D40

The best way to check fitment is to remove the faulty alternator from the vehicle and compare it with the new alternator, make sure the outer appearance, regulator plug type and part number all match. The part number of an alternator is typically printed or engraved on the alternator.

 

The image above shows the part number on the alternator of a Subaru vehicle. 

 

 

Product Options

• Genuine alternator

Genuine alternators are made by the Original Equipment (OE) manufacturers that also supply parts to your car's brand. For example, BMW vehicles typically use Bosch or Valeo alternators, while Toyota vehicles often come equipped with Denso alternators. 

OE manufacturers have highest production and quality control standards, and they have extremely low failure rates. Genuine alternators are designed to last for at least 5-10 years under normal driving conditions. They usually come with a one-year manufacturer's warranty.

However, a genuine alternator can be very costly, e.g. a genuine alternator for BMW X5 can cost $1800. Meanwhile, not all genuine alternators are readily available in Australia. In many cases, dealerships need to order them from countries like Japan or Germany, which can take up to two months for delivery. If make an order by mistake or change or mind, genuine alternator is not refundable.

Furthermore, making a warranty claim for a genuine alternator is often challenging. OE manufacturers are so confident in the quality of their products and may easily reject warranty claims unless comprehensive testing or clear evidence proves the alternator has a manufacturing defect and the vehicle has no other issues affecting the alternator. 

 

•   Aftermarket alternator

Aftermarket alternators are built by third-party manufacturers. They are designed to function and perform similarly to the original alternator but they have much more competitive prices. There are many major aftermarket brands on the market and our own brand, Canton Auto Parts, is one of the emerging aftermarket brands in Australia.

Aftermarket alternators vary in their brand, quality and price. Many customers who research online come across “too good to be true” low-priced alternators on online marketplaces. For example, some alternators listed on platforms like eBay are priced at just over $100.

The reality is that most of these low-price alternators are made with poor quality components. As a result, they tend to have significantly higher failure rates and much shorter life span, and can potentially further damage to the vehicle.

Our manufacturing partners are ISO 9001 certified and have strict quality control processes and product standards, significantly reducing failure rates during mass production. Our products are built with high quality electrical components, including regulator, pulley, rectifier, bearing etc. They are designed to meet or exceed OE products.

In some cases, aftermarket products can actually be an improvement over the original alternator, as many aftermarket manufacturers have their research team and engineers to address and correct design flaws found in the original alternator.

 

 Alternator Warranty 

Due to mass production nature of electrical components, it is hard to avoid product failures. Having genuine warranty on alternator is essential for peace of mind and protection. Most genuine alternators come with one-year manufacturer’s warranty.

It is worth noticing some online retailers advertise 5 years, 10 years or even life time warranty. These warranties can be misleading; some sellers fail to honour their warranties when the product fails within the stated period. For example, one of my customers attempted to make a warranty claim from an online retailer and he was told to pay extra for the replacement alternator. 

The image above shows an example of one of online retailers who refused to honour their stated warranty

We are an Australian-owned and operated business. Our alternator products come with one-year Australian warranty. For full details, please refer to our warranty policy.

 

Final thoughts 

Whether you’re shopping online, at a local store, or through your local mechanic, this guide gives you the confidence to make the right choice.  Don't settle for the cheapest option. Having a good alternator can save you from a lot of trouble.