Why is the alternator important?

The alternator is the main component in your vehicle’s charging system. It converts mechanical energy into electrical energy, supplying the battery with a constant source of power.

Without the alternator, the battery will not be able to stay charged. This is due to the alternator not providing the necessary power to the battery. A failed alternator will make your car unusable until the alternator is repaired.


What causes the alternator to not charge the battery?

  • Burnt out diodes – The diodes convert the electricity from AC to DC. Exposure to extreme heat or short circuit can cause the diodes to burn out. If a diode fails, the alternator will struggle to provide the battery with the required amount of power.
  • Damaged belt/pulley – An alternator drive belt transmits mechanical power from the engines crankshaft to the alternator pulley , which is turned into electrical power by the alternator. If this belt/pulley fails, your alternator will not be able to produce any power, resulting in the battery being starved of energy.
  • Damaged alternator clutch pulley – some modern alternators have a clutch pulley (rather than just a fixed / static pulley). If the clutch pulley fails it will often make noise while rotating and can either reduce the alternator charging output, or stop it all together.
  • Bad wiring – There are many wires that connect to your alternator. If any of these wires become damaged or disconnected from the alternator, it could lose output charging power.
  • Damaged internal component – Inside the alternator are several components such as the bearings, stator, rotor and cooling fan. These parts can become damaged over time, resulting in it not being able to convert energy correctly.
  • Dirty battery terminals – The terminals on your battery can become corroded, limiting the alternator’s ability to charge it. This corrosion can usually be scraped off.


Symptoms of an alternator not charging the battery:

A failing alternator will display the following symptoms:

  • Battery / Starting problems – The most obvious symptom is that the battery is not holding a charge. Your vehicle may fail/struggle to start and lose charge after short amounts of time while driving. This can cause your vehicle to start running rough, lose power and then stop altogether, while driving which is a dangerous situation to be in, especially at night / rain or in heavy traffic / roundabouts and so on.
  • Lighting problems – Lower battery power can cause the headlights and dashboard lights to flicker or lose brightness.
  • Alternator Screeching or Squealing noise – Your vehicle may produce a screeching or squealing noise that get worse when you rev the engine up. This can be due to the belt being slightly loose or worn and not working correctly.To test if the alternator drive belt is the making this noise, often carefully pouring cold water on to the alternator drive belt while the engine is running will quieten the noise down.Often the simple solution to prevent the alternator drive belt making the loud and embarrassing screeching or squealing noise is to tighten the alternator drive belt to the correct belt tension. Please be very careful not to over tighten the drive belt, as this can quickly damage alternator bearings and other bearings for other items driven by the drive belt such as the water pump, air conditioning pump and so on.

    We recommend that you get the alternator drive belt tighten and tensioned correctly by your trusted local mechanics.

  • Grinding / Clicking / Rattling or Rumbling noise – Worn out or damaged alternator bearings may also cause an alternator grinding / clicking / rattling or rumbling rattling noise. The easy way to test if this noise is coming from the alternator (or some other engine part) is to disconnect the alternator drive belt (for a very short time) and run the engine. If the noise has no gone, then it is likely the alternator bearing have please
  • Battery light – The battery light may appear on your dashboard, warning you of a fault in your alternator/charging system. If this happens you should immediately take to your trusted automotive repairer, otherwise your vehicle will quickly become unreliable.


Alternator Diagnostics and Replacement in Hamilton

Is your battery not charging correctly? If so, we can help you.

At Grimmer Motors, we can provide advanced diagnostics for your car’s alternator/charging system. If the alternator is damaged, it is usually more cost-effective to replace the entire alternator rather than individual parts. Replacing the alternator will allow your battery to stay charged, reducing the risk of it going flat while driving, causing you to breakdown, and needing jump-starting. If the battery needs replacing, we can install a new one in your vehicle.

For fast, friendly high-quality battery and alternator charging system diagnostics replacements in Hamilton, contact Grimmer Motors today!


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