An alternator is a crucial part of a car battery. It converts chemical energy into electrical energy for a car’s running. It also powers other car components and accessories. However, at times, an alternator can become overcharged and malfunction. It occurs due to numerous reasons. That said, we have compiled a list of different causes of alternator overcharging and how to fix it.
But first, we will go through the symptoms to help identify this problem in car alternators.
ALTERNATOR OVERCHARGING SYMPTOMS
An alternator overcharging means it generates more than the required voltage. A 13.5 or 14.4-volt output is a standard for alternators. At times, some car parts malfunction, indicating such problems. It is easy to confuse these symptoms with a bad car battery or an alternator. To clear up this uncertainty, let’s go through the common symptoms of an overcharging alternator.
Flickering Dashboard Lights or Headlights
One might notice flickering headlights or dashboard lights due to excessive power output. It happens when the alternator pumps more charge, making the lights too bright and then back to normal.
Shortened Bulb Life
An overcharging alternator affects car electronics. Since there is too much power supplied to electric components, it puts an increased strain on the components. As a result, they wear out faster. Car bulbs have a different average life span, depending on their type. These include:
- Halogen: 450 to 1,000 hours
- HID: 6,000 to 24,000 hours
- LED: 30,000 to 50,000 hours
High Voltage Readings
Another sign of alternator overcharging is high voltage readings. A voltage reading above 14.5 volts on the vehicle’s voltmeter or dashboard gauge indicates overcharging. When voltage ratings are unbalanced, they also create an open loop fault in cars.
Strange Smells
Overcharging leads to excessive heat in the alternator. As a result, a burning smell emanates from the engine compartment. It indicates the formation of hydrogen sulphide gas and that battery is no longer safe to use.
Battery Damage
Over time, an overcharging alternator damages the vehicle’s battery. Excessive voltage causes the battery to overheat, dry out and have a reduced lifespan. It also causes the battery to corrode and one might notice a bulge in the battery. This will also lead to the car battery not charging.
Battery Warning Light
Many modern vehicles have a car battery warning light on the dashboard. If this light is illuminated while driving, it could indicate an issue with the charging system, including potential overcharging.
How to Test an Overcharging Alternator?
It is important to confirm that the alternator is indeed the problem if the car shows the above-mentioned symptoms. Therefore, here are the steps on how to test an overcharging alternator:
- Disconnect the battery cables to prevent any sparks from occurring while testing the alternator.
- Set the multimeter to DC voltage with a range set to 20 volts or more.
- Touch the red probe of the multimeter to the positive battery terminal.
- Touch the black probe of the multimeter to the negative battery terminal.
- Start the engine and let it run for a few minutes.
- The multimeter should read between 14.2 and 14.7 volts. If the reading is higher than 14.7 volts, then the alternator is overcharging.
- Turn on the headlights and other electrical accessories. The multimeter reading should not change significantly. If the reading does change, then there may be a problem with the alternator or the electrical system.
- Turn off the engine and reconnect the battery cables.
ALTERNATOR OVERCHARGING CAUSES
Now we are aware of the common symptoms of alternator overcharging which lead to different issues such as a car dying while driving. Let’s learn the common causes.
Voltage Regulator Malfunction
The voltage regulator is a critical component of the charging system in a car. It regulates the output voltage of the alternator to power the vehicle’s electrical systems within the required range. If the voltage regulator fails, it can cause the alternator to generate excessive voltage, leading to overcharging of the battery. This results in damage to the car battery and other electrical components.
Wiring Issues
The connection between the alternator and the battery is crucial for the proper functioning of the charging system. If the connections are loose or corroded, it creates a resistance in the circuit, causing voltage fluctuations. These fluctuations cause the alternator to produce higher voltage levels than necessary, resulting in overcharging.
Faulty Engine Control Module (ECM)
The Engine Control Module (ECM) controls various aspects of the vehicle’s electrical system, including the alternator. It might malfunction or send incorrect signals to the alternator. As a result, a faulty ECM causes overcharging.
Problems With the Car’s Electrical System
The alternator’s voltage output is influenced by the demand from the vehicle’s electrical system. If there’s a malfunction or excessive demand from various components like car headlights, it causes the alternator to produce more voltage than required.
Short Circuit in the Alternator
A short circuit within the alternator’s internal components can disrupt the normal flow of electrical current. It also causes irregular voltage output leading to damage in car computers. If certain parts of the alternator become short-circuited, it leads to overcharging of the battery. Moreover, short circuits can occur due to wear and tear, manufacturing defects, or damage caused by external factors.
Bad Alternator Bearing
The alternator contains various internal components, including bearings that allow the rotor to spin smoothly. If one of these bearings goes bad, it causes the alternator to spin irregularly or produce excessive friction. This leads to alternator overcharging. In addition, a failing bearing might produce unusual grinding or whining sounds.
ALTERNATOR OVERCHARGING FIXES
There are two practical ways to fix an overcharging alternator. They include the following methods.
Replace the Voltage Regulator
Here’s how you can do so.
- Begin by disconnecting the negative (black) cable from the battery to ensure safety and prevent any electrical mishaps.
- The voltage regulator is usually located on the alternator itself. It might appear as a small box attached to the back of the alternator. In some cases, especially in older vehicles, the voltage regulator is a separate component mounted elsewhere in the car.
- Use the appropriate car mechanical tools to carefully remove the screws or bolts holding the voltage regulator in place.
- Ensure that the new voltage regulator is the correct type for the car’s make and model. Align the new regulator with the mounting holes and secure it in place using the screws or bolts removed earlier.
- Reattach the negative (black) battery cable to its terminal. This will complete the replacement process.
Replace the Alternator
If the regulator is a functioning problem, then the problem lies within the alternator. Here’s how to replace an alternator with these steps.
- As with the voltage regulator replacement, start by disconnecting the negative (black) cable from the battery.
- Locate the alternator in the vehicle’s engine bay. One or more bolts are securing it in place. Using the appropriate tools, carefully remove these bolts and set them aside.
- The alternator is connected to the electrical system through a series of wires. Disconnect these wires, making sure to note their locations for reconnection.
- With the mounting bolts and wiring disconnected, remove the old alternator from its position.
- Position the new alternator in the same orientation as the old one and secure it with the previously removed mounting bolts.
- Reconnect the wires to the new alternator in the same locations from which they were removed earlier.
- Tighten the mounting bolts to the manufacturer’s recommended torque specifications. This ensures that the alternator is properly secured in place.
- Finally, reattach the negative battery cable to its terminal.
Apart from the above-mentioned methods, it is suggested to seek professional advice. Also, always refer to the vehicle’s repair manual for specific instructions and safety precautions. Regular maintenance of the car battery, alternator and electrical system also helps prevent issues like overcharging.
FAQs
What causes an alternator to overcharge?
Alternator overcharging is caused due to multiple reasons. These include wiring issues, bad alternator bearing, faulty ECM and issues in the voltage regulator.
How to fix an alternator overcharging?
An overcharged alternator can only be replaced with a new one. If the voltage regulator is the issue, it must be replaced.
Is 15 or 17 volts too high for an alternator?
The normal voltmeter reading for an alternator is between 13.5-14.5 volts. If it exceeds the limit, then there is a problem with the alternator and it is generating charge more than required.
All in all, these were the symptoms and causes of alternator overcharging. We have also provided common fixes to solve the issue. Therefore, if you find such issues persistent in your car, it is time for a change. Go through these used cars for sale in the UAE for budget-friendly options.
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