The alternator on a car engine: operation, utility and cost of replacement

The characteristics of the alternator

Key piece of a vehicle in good working order, the alternator must always function correctly. In the engine compartment, it is usually attached to the front face of the vehicle's engine block, not far from the starter. This is directly connected to the camshaft via a timing belt or alternator which transmits to it a movement identical to that of the engine.

The alternator is quite simply a small current generator cylindrical consisting of a magnet and a coil made with copper wire. Functioning like an electromagnet, the alternator is based on a simple principle, which involves rotating a magnet inside a copper coil. This rotation will generate an alternating current. The energy created feeds the electrical circuits and recharges the battery: this principle is called electromagnetism.

Only vehicles with thermal engines (hybrid cars also belong to this category) need an alternator given that the 100% electric motors are constantly recharged with electricity.

Its function within the car

Indispensable for starting, the alternator allows the vehicle's battery to be recharged by converting the mechanical energy of the motor into electrical energy. Its role is to take over from the battery after the car has been started, when the engine is running, it remains on so that the current passes from the engine to the various electrical devices such as lighting, the car radio, the engine. power steering or air conditioning.

It is for this reason that any vehicle that has been stationary for a long time will be unable to start, quite simply because it will not have driven and that the The alternator was unable to create an electric current to recharge the vehicle's battery, which drained over time. The charge of your battery is ultimately proportional to your driving frequency.

Maintenance, replacement and cost of the alternator

Vital to the proper functioning of your car and for the keeping its electrical system powered, the alternator must therefore be monitored to keep your car in good working order. It is easy to tell when it is faulty since the battery indicator light will automatically illuminate on the dashboard if it encounters any failure. If the light remains off and there is indeed a fault, then the battery charge will drain over time until it is empty. This will not prevent the vehicle from restarting, but it will stall constantly and it will require you to buy a new battery in addition to your alternator if it is broken.

An alternator does wear out. not and is supposed to work for the life of your car, if it breaks down it must be replaced right away.

Dismantling and replacing an alternator is still a investment to be taken into account since depending on the make and model of your vehicle, its price can range from 150 to 600 € when it is changed without including the cost of labor!

Check the condition of its alternator

Performing the test to find out if your alternator is out of order is relatively simple, all you need is an ammeter, a voltmeter or a multimeter that can be found at around twenty euros in a DIY store. Once switched on, you must first connect your multimeter to the appropriate terminals of your battery using the two black and red colored cables. You will need to measure the battery voltage in volts. If it is greater than 12.2V you can then test your alternator. Then, when your engine is running at around 2000 RPM, check the voltage displayed on your multimeter. If it is between 13.3V and 14.7V then there is nothing abnormal to sign. However, if this is not the case, and it is less than 13.3V then the alternator must be replaced: it is at the end of its life. Conversely, if the voltage exceeds 14.7V, the alternator regulator must be changed: It is no longer able to limit the supply of electricity. This surge could burn out your car accessories. If your vehicle has a "stop and start" button, an alternator can display 15V or 16V, or simply display 12V.

If the alternator is not the cause, then you have to be careful to the alternator belt or the accessory belt connecting the engine to the alternator. It should not be too tight or too loose in order to ensure proper operation of the alternator and to prevent your battery from being charged.

If the belt breaks, the distinct noise that it will alert you immediately and allow you to replace it as soon as possible.

To change it, just buy one of the same dimensions (similar width and length) and make an exchange standard between the two.It should be noted that in addition to having to be checked at least every 50,000 kilometers, the belt wears out over time due to its composition, mainly made of rubber, aramid and fiberglass .

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Buy your used car with confidence with Capcar! Capcar always ensures the proper functioning of the alternator and the battery. Indeed, all our cars are checked with a fine comb before being put on line on our site. With Capcar you know exactly what you are buying, so go ahead and trust Capcar!