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Car Care Advice

All You Need to Know About Your Car’s Charging System

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Wondering how your car’s charging system powers up your car?

The charging system comprises three important components, namely the alternator, voltage regulator, and battery that provide electrical power for your vehicle’s operating needs. 

These components perform critical functions like charging the battery, firing the spark plugs during combustion, and powering the car’s electrical and starting system.

Read on for a lowdown on the crucial components of a car charging system, signs of damage, and replacement costs.

This Article Contains:

How Does Your Car Charging System Work?

Your car’s electrical system runs throughout the vehicle, supplying power to various electrical components, including:

The primary elements of charging systems are the alternator, battery, and voltage regulator. A complex wiring harness connects these components to the other parts of the vehicle’s electrical system. 

Here’s the step-by-step process of how car battery charging systems work:

  1. The battery converts chemical energy into electrical energy.
  1. The battery terminal and battery cables facilitate electrical current flow to the car.
  1. As you turn on the ignition switch, the current engages the starting system, comprising relays (starter solenoid), fuses, and the starter motor.
  1. The relays and starter solenoid convert the low amperage signal from the ignition switch to a high amp current, which activates the starter motor.
  1. The starter motor turns the engine over, activating the ignition system and allowing the air-fuel mixture to enter the cylinders. This leads to the combustion process that kickstarts the engine. 
  1. The rotational force of the engine’s crankshaft turns the drive belt pulley. The drive belt uses the mechanical energy (generated from the crankshaft’s rotation) to power up the alternator.
  1. The alternator recharges the battery.

Note: The charging system of an electric vehicle is different from that of gas-powered cars, which run on internal combustion engines. You can charge an EV battery by directly plugging the battery charger into an external electricity source. A battery connector called the Megawatt Charging System is also being developed to cater to the charging needs of an electric vehicle with a large EV battery.

Now, let’s examine the charging system components that produce the electrical power for your car — starting with the alternator.

How Does an Alternator Work?

The alternator is typically mounted outside the engine and connected to the crankshaft by a drive belt.

It converts the mechanical energy of your engine’s rotation into the electrical energy needed to run the vehicle. The alternator also recharges the battery, replenishing the power used during the starting process (when the car relies on the battery alone).

Here’s how:
The alternator generates Alternating Current (AC) power, which is converted to Direct Current (DC) power. Three crucial components, the rotor, stator, and rectifier, facilitate this process inside the alternator. 

The rotor (an electromagnet) and the stator generate electricity. The rectifier then converts the current to meet the electrical demand of car accessories and delivers the electrical charge to your battery. A series of six diodes (two for each of the three sets of windings in the stator) facilitate the conversion of AC to DC.

Without a properly functioning alternator, your battery cannot maintain its fully charged state. Let’s find out how to spot alternator damage.

What Are the Symptoms of a Bad Alternator? 

Some of the telltale signs of a bad alternator are:

  1. While the battery warning light typically indicates a battery-specific problem (or loose battery connections), it can also indicate a bad alternator. The alternator may be putting out electrical voltage that is either too high or too low.
  1. The drive belt rotates on a shaft supported by bearings to power the alternator. A problem with either of these items can cause a whining noise from the area of the alternator.
  1. Burning wire or rubber smell is another indicator of a bad drive belt, bad alternator, or both. Excess friction on the belt, failed components inside the alternator, or a combination of both can cause this. 
  1. Since your alternator charges the battery and fires the spark plugs, it won’t provide sufficient current flow for starting and driving if it’s faulty. 
  1. Sometimes, a dead battery may be a symptom of a bad alternator. If the alternator doesn’t generate enough electrical voltage, the battery won’t fully charge and eventually fail. 
  1. If your alternator is putting out the incorrect battery voltage, your headlights may appear too bright, too dim, or flicker as you drive. 
  1. A failing alternator that isn’t putting out sufficient power can cause your power windows and seats to operate slowly. Alternatively, you might be unable to meet the electrical demand to power up your car stereo, cigarette lighters, AC blower fan, and interior lights. 

So, how much will you spend switching your damaged alternator with a new one?
Read on to find out.

How Much Does It Cost to Replace an Alternator? 

Alternator replacement could cost between $750 and $850, depending on your car’s make and model, the type and quality of the parts used, and the mechanic’s labor charges. 

Let’s move on to the next component in your vehicle’s charging system — the voltage regulator.

How Does a Voltage Regulator Work?

A critical component of typical charging systems, the voltage regulator, regulates the system voltage generated by the alternator (alternator output). Depending on the vehicle, the voltage regulator can be located inside or outside the alternator or built into the Engine Control Module (ECM) on newer vehicles.

Did you know?
The alternator can produce a battery voltage higher than what your car’s charging and electrical system can safely handle. The voltage regulator keeps the alternator output within the proper range, minimizing the risk of overcharging. The voltage reading should typically lie between 13.8 volts and 14.6 volts. 

This voltage will power the car’s electrical components and recharge the battery without causing any problems.  

But how can you tell if the voltage regulator is bad?
Let’s find out.

What Are the Symptoms of a Bad Voltage Regulator?

Here are a few signs that may indicate voltage regulator failure:

  1. A dead battery, corrosion on the battery terminal, need for frequent battery water replenishment, or a warped battery case
  2. Dimming, flickering, pulsing, or prematurely burned-out bulbs
  3. Dim lighting, erratic or non-functioning speedometer, or inconsistently working infotainment systems
  4. Sputtering, stalling, jerky acceleration, rough idling 
  5. The check engine light or battery light comes on 

If you have a bad voltage regulator, you’ll probably need to replace it.

How Much Does It Cost to Replace a Voltage Regulator? 

You’ll likely need to spend between $180 and $380 to replace a bad voltage regulator. This includes labor costs ranging from $140 to $240, as most voltage regulators sit inside the car’s alternator, making it difficult to access. 

Next, we’ll explore the ins and outs of the battery.

How Does a Car Battery Work?

Your car’s battery provides the energy needed to start your vehicle. When your engine is shut off, the battery powers the vehicle’s radio, clock, security system, and computer memory.

Here’s how:
The battery consists of a plastic case containing lead and lead dioxide plates. These plates are submerged in an electrolyte solution of sulfuric acid and water. A chemical reaction between the plates and the electrolyte produces an electrical current that allows the battery to do its job. 

So, what happens when your car battery goes dud?
Let’s find out.

What Are the Symptoms of a Bad Car Battery?

Your car battery might begin to fail without routine maintenance or when it reaches the end of its lifespan

When that happens, you may notice:

  1. It gets harder to start your car
  2. You need to charge your battery with a battery charger frequently
  3. Your interior lights and headlights become noticeably dimmer
  4. Some of your vehicle’s power accessories don’t work 
  5. Your battery warning light comes on
  6. The case of your battery is bulging, cracked, or leaking  
  7. Your car’s fuel economy has reduced

Wondering how much it’ll cost to replace a bad battery? 
Read on for an estimate.

How Much Does It Cost to Replace a Car Battery? 

You can purchase a standard flooded lead-acid battery for $185 to $300. A premium AGM battery will cost you around $250 to $400. In addition to the battery costs, you’ll need to pay labor charges to remove your old battery and install a new one.

Now that you’re familiar with a vehicle’s charging system components, let’s see why it could malfunction.

What Causes a Charging System to Fail? 

There are multiple reasons for battery charging system problems, including:

  1. The car battery isn’t working 
  2. The battery connections are bad (loose, cracked, or corroded) 
  3. The alternator is malfunctioning 
  4. The alternator belt is worn out or loose 
  5. A fuse has blown 
  6. The voltage regulator is damaged 
  7. There is a wiring problem 
  8. The engine computer has broken down 

Because the charging system is complex, it’s best to have an auto repair technician troubleshoot the issue and fix it correctly as early as possible! 

Fix Charging System Woes with AutoNation Mobile Service

A properly functioning car charging system is crucial for smooth vehicle operation. Not to mention that routine maintenance and timely repair can help prevent charging system failure. 

However, locating and fixing a malfunctioning component can be complex, so it’s best left to professionals like AutoNation Mobile Service. We’re a mobile auto repair and maintenance company offering transparent pricing and a 12-month, 12,000-mile repair warranty on auto parts.

Contact us to get your car charging system fixed right from your driveway.