What is an alternator and how much does it cost to repair?

If your car’s electricals are failing, or have stopped working entirely, then the alternator could be the cause. But what does an alternator do? And how much does it cost to fix?

In this guide, we’ll explain the role an alternator plays in your vehicle, some signs to look out for that indicate your alternator might need replacing, as well as more details about how to get a new part and how much a repair might cost you.

The alternator is the component of your car that charges your battery whilst the engine is running and powers the electrical systems of your vehicle, by converting mechanical energy generated by the engine into electrical energy.

The electrical energy produced is an alternating current (AC), but your vehicle needs a direct current (DC), so a mechanism called a rectifier converts the AC into DC so that it can power your electricals. The alternator also contains a component called a voltage regulator, which is responsible for keeping the current that flows to the battery steady.

A faulty alternator won’t be able to recharge your battery, meaning you’ll struggle to start your car without manually charging your battery. If you suspect an issue with your alternator, head to your local Halfords garage and we'll be more than happy to inspect it for you.

There are a few common warning signs that indicate your alternator is failing and you may need a replacement. These include:

• A battery warning light on your dashboard
• Flickering, dim, or unusually bright interior and exterior lights
• Your vehicle struggles to start or stalls often
• Electrical features in your vehicle aren’t functioning as usual (windows taking longer to raise or lower)
• Growling or whining noises

There’s no exact time limit that an alternator should last; it will depend on several factors including the quality of the alternator, the overall condition of your vehicle, and how much power the alternator is having to provide.

On average, you can expect the alternator to last around 80,000 to 150,000 miles.

Here at Halfords, we have a huge range of alternators for all car makes and models, from popular brands such as Bosch, Lucas, RTX and Starline.

The cost of an alternator replacement will depend on the make, model, and specification of your vehicle, but it couldn’t be easier to find the right part for your car. Just enter your registration number into the online tool provided and we’ll match you with the products that fit your car.

Once you’ve found the right part, you can have them delivered or opt for our convenient click and collect service, so you can get straight to fixing. If you’re still not sure of the right part, just visit your local Halfords store where one of our colleagues will be happy to help.

Once you suspect that your alternator is failing, try to get it seen to as quickly as possible – a worn-out alternator won’t recharge your battery, so you’ll only be able to drive for short time before the battery will need to be manually recharged.