Alternator Overcharging

There are various different parts that make up a vehicle’s starting & charging system, which are all extremely important. The operation of the vehicle would be adversely affected if any of these applied parts failed at the same time, with the worst-case scenario leaving a driver stranded.

The vehicle alternator is among the starting and charging systems’ most frequently misunderstood parts. All of the vehicle’s accessories can be run when an alternator is operating as it should. With this knowledge, one can as well infer that an alternator that isn’t working well won’t be able to supply enough power to carry out this task effectively.

Many drivers are unaware that an alternator might malfunction in other ways. Actually, a damaged alternator frequently overcharges rather than undercharges, which causes a very distinct set of problems.

Continue reading to find out more regarding the signs of an alternator that is overcharging and how to fix them if you ever experience them.

What Is An Alternator?

The alternator’s in charge of charging the car’s battery, to put it simply.

In reality, it powers some of the car’s appliances while also charging the battery. Everything is dependent on the immediate output of:

  • the alternator
  • the battery
  • the electrical consumption of the vehicle’s system

These components continuously change their current outputs and draw. Was it supposed to convey 1A or 30A? For instance, charging the battery might become rather challenging.

The battery won’t recharge while you’re driving if there is an insufficient charging current. Sometimes until you stop the car, you won’t notice anything, but this could result in a dashboard battery indicator. The following time you approach it, it won’t turn on.

The power source will overload with an excessively high charging current. This article’s topic is just that. For additional information on what overcharging an alternator is, scroll down.

How Does An Alternator Work?

The acid solution’s ions are attracted to the cell plates by a battery to produce power. In other words, this induces a current by causing an unbalanced charge, which drives the movement of electrons.

The purpose of an alternator is to turn this chemical process around. Because of its charge, the ions are returned to the solution. As a result, they are free to respond once more, which allows the battery to keep running.

A simplified version of an alternator’s operation is shown below:

The crankshaft – , the focal point of an engine, – turns due to the standard ICE process.

It is connected by a pulley. A belt is fastened to the pulley. When the hood is opened, you can see that belt. Several additional pulleys are spun by this serpentine belt drive. The alternator is one of them.

The belt spins an electromagnetic rotor within a stator housing.

As the vehicle starts, the battery supplies power to the electromagnetic rotor. When the engine is operating independently, the alternator provides this current directly. It kind of runs on its own power.

The stator has three sets of interlocking wiring grounded to the same point.

All three of the wire coils experience current induction while the electromagnetic field rotates over the wiring for the stator. A three-phase alternating current (AC) occurs due to this.

Car circuits use direct current (DC). The AC passes through a rectifier to convert it to DC.

Finally, when the engine is running, a car’s circuit operates at roughly 14 V. The alternator will create considerably excessive potential, much greater than 14 V, if left unregulated. The puzzle’s last piece is a regulator. A Circuit board is used to monitor the amount of current being drawn from the alternator. It then modifies the input’s current into the electromagnet of the rotors in accordance with this.

What Does It Mean When Your Alternator is “Overcharging”?

The phrase “overcharging” is frequently used to indicate an alternator that is providing more output than it’s rated for.

All alternators are pre-disposed to produce a voltage as a result of the output that falls in a certain range, therefore this justifies a sufficient comprehension. This range represents the working limit at which the electronics of a specific vehicle are intended to operate.

Sensitive electrical parts can be swiftly destroyed by an overcharging alternator, rendering them worthless. In the end, this calls for expensive repairs that are significantly more expensive than buying a new alternator to fix the problem.

A voltage regulator built into an alternator controls its output and is intended to avoid overcharging. Voltage regulator malfunction, however, is a possibility and does happen occasionally. This causes the production of extra voltage to start up quickly.

Most alternators include integrated voltage regulators that are configured to restrict output to between 13.5 and 14.5 volts. As a result, any alternator that produces an output voltage of more than 14.5-15.0 volts may be considered defective due to an overcharging circumstance.

For your specific vehicle, manufacturing-specific service information should always be consulted to verify this.

What Are The Symptoms Of An Alternator That Is Overcharging?

When the alternator is running, a high voltage measurement is the most typical sign of an overcharging alternator. Harm to the electrical or charging system is frequently one of the first indicators of overcharging.

When the engine is operating, the majority of conventional automobile alternators will produce a voltage of 13.5 to 14.5 volts. On some automobiles, an alternator will frequently deliver 16 volts or more for brief lengths of time, but this is not unusual. Depending on the car, a particular voltage may indicate an alternator that is overcharging.

The car and how much electricity it needs to operate all its electrical systems will determine everything. In addition to using specialized batteries designed for usage with hybrid drivetrains and stop-start technology, many modern automobiles also use brake regeneration to provide electrical power.

High Voltage Reading From The Alternator When The Engine Is Running

An alternator that continuously produces a voltage that is higher than usual while the engine is operating is among the most common indications that an alternator is overcharging. On engine start-up, the alternator volts will typically be a bit higher than normal, but after the ECU has evaluated the present engine state and power demands, it should return to a normal voltage range.

If the car is more recent, the ECU is partially in charge of controlling the output of the alternator. The alternator’s output is modified to meet the vehicle’s power requirements. Diagnostic equipment is required in this situation to check the alternator’s status under various load scenarios to determine whether it’s overcharging.

An alternator output test with a multimeter is typically sufficient for older cars. The power generated ought to be pretty consistent, but it might increase by about 2 volts if a higher power is required (For instance, while the air conditioner is on and the headlamps. are on). When the battery is being overcharged by the alternator in older automobiles, the voltage dial over the dashboard may occasionally sound an alarm.

Physical Damage To The Battery

Examining the battery’s condition is an additional method of spotting an overcharging alternator. Batteries in newer cars typically have monitoring systems that keep track of their condition and prevent excess voltage from harming them. When there is an issue like overcharging, a red battery indicator will typically display on the dashboard of these cars. In order to prevent the battery from fully charging when the ECU discovers an issue, it may limit the volume of electricity that can reach it.

Older cars and equipment that lack an ECU for alternator monitoring typically let the alternator charge the battery excessively till it breaks. Swelling and cracking of the battery cover due to gas accumulation and electrolyte fluid leakage in the battery are indicators of an overcharged battery’s deterioration. Following an overcharge, a battery would typically feel warm to the touch. After being persistently overcharged, certain batteries might even begin to leak.

Check the Engine Light On the Dashboard

On more recent vehicles, an overcharged alternator will set off several error codes, which will typically result in the dashboard examining the engine light coming on. Modern automobile charging devices are managed and controlled by the ECU, as was just mentioned. The ECU occasionally has the ability to modify the quantity of electricity it generates. The ECU will record any alternator issues, such as overcharging, in memory, then take the required precautions to safeguard the battery and the remaining charging system.

P2504 Charging Device Voltage High is a frequent error message in this situation. In the event that the ECU detects excessive volts inside the charging device, this error is set off. It frequently indicates an alternator that is overcharging, but it could also be brought on by issues with other components, like a defective voltage regulator, faulty battery connections, or rust in the battery connectors.

Alternator Overcharging

Frequently Blown Fuses And Bulbs

The power system inside the car getting damaged is another sign of an overcharging alternator. Fuse and light bulbs repeatedly blowing as a result of voltage spikes is a common place to start. As a result of the ECU’s increased surveillance of charging systems nowadays, this symptom is less frequent, but in older automobiles, it may quickly turn into a serious issue if left unattended.

The charging system’s wiring looms may eventually get scorched or brittle due to an overcharging alternator’s damage. Should the alternator not be fixed or replaced, this may occasionally result in vehicle fires. It’s not as prevalent in newer cars, but it still can happen; hence, it wouldn’t be wise to disregard the dashboard’s red check engine or battery lights for an extended period of time after it shows.

Battery Fails Quickly After Replacement

The battery’s lifespan will be significantly shortened if it is continuously overcharged. Traditional sealed automobile batteries have an electrolyte of sulfuric acid & distilled water, which enables the battery to be charged and discharged repeatedly. The battery’s internal liquid heats up due to continuous overcharging while the engine’s operating, triggering a chemical process that produces oxygen and hydrogen.

An overcharging battery rarely explodes since sealed batteries in cars typically have an exhaust system to let these gases out. The battery’s capacity to effectively discharge & recharge is diminished by the loss of electrolytes, though.

The acidic electrolyte in AGM batteries, which are commonly found in newer cars, is linked to a mat with a fleece texture to assist in preventing overcharging-related electrolyte damage. As a result, charging & discharging can happen more frequently.

How To Identify Alternator Overcharge

The alternator voltage should be 14.2 volts; however, the vehicle battery is programmed to operate at 12.6 volts. These numbers, along with a multimeter, make it simple to determine whether your automobile is being overcharged by the alternator.

Step By Step Instructions:

  1. Put 20 volts of DC on the multimeter.
  2. Connect the black probe to the negative battery clamp as well as the red probe to the battery clamp’s positive terminal.

When the engine is off, the battery’s base reading ought to be 12.6 volts or perhaps higher than 12–12.2 volts.

  1. Launch the engine. As soon as the alternator starts charging the battery, the voltage reading ought to be from 14.2 to 14.7 volts.
  2. Set the radio, hazards, and headlights to on. Ideally, the reading ought to be above 14 volts, which is still greater than the voltage of the base battery.
  3. A failing battery may have volts below 12.2 volts. After at least thirty minutes of driving, inspect the automobile once more. We need to take the alternator out of the equation when the battery’s voltage remains low in order to determine the cause.
  4. The 14.2-14.7 voltage range is where the alternator functions. This wattage is sufficient to swiftly and securely charge the battery. As the alternator must also give electricity to the headlights as well as other power users, doing so may cause a tiny drop in voltage.
  5. It is obvious that the alternator’s not generating enough power should the voltage falls less than 14.2 volts when the vehicle is not under load or less than 12.7 volts when it is. The battery is dying, though, when the alternator’s producing adequate power however the battery is still below 12.6 volts.

When the engine is operating, the volts reading will exceed 14.7 volts, which makes the overcharge the easiest to diagnose. Although it doesn’t provide a clear description of how to resolve the issue, the following footage does demonstrate how to set up and interpret a multimeter for voltage.

How To Fix An Overcharging Alternator

There are a couple of short-term workarounds for the issue that I’ve observed, but I don’t advise trying them. An overcharging alternator can only be rectified by taking it apart and having it fixed or by installing a new one; therefore, the issue must be handled carefully.

You’d need to open that alternator and possess advanced electrical system expertise to repair the voltage regulator, which is a task beyond the scope of a do-it-yourself technician. A new alternator can be purchased from Amazon or a nearby parts store, or we can seek assistance from one of the many alternator repair services.

The job’s level of difficulty is determined by where the alternator is. The task is very simple if it is easily accessible, but if it is hidden deep within the engine’s bay, you will need to remove pieces that are in the way. The best approach to reach the alternator in that situation will be demonstrated in a vehicle-specific guide, which I would urge you to search for.

Step By Step Instructions:

  1. Remove the battery’s negative terminal connector.
  2. By removing obstructions, you can make room around the alternator to perform repairs. A lot more labor will be involved if the coolant pipes are removed.
  3. Release the alternator pulley’s serpentine belt tensioner, then remove the belt.
  4. The alternator’s power plugs must be unplugged. To remove the alternator bolts, use the largest ratchet and a socket.
  5. To improve the connection, clean the nuts and bracket for the alternator with the wire brush.
  6. Align the alternator with the bracket. Apply anti-seize to the threads of the bolts before inserting them in the alternator’s holes.
  7. Bolts should be manually tightened in pairs, so they descend uniformly. Use the ratchet to complete the task.
  8. Reconnect the wires to the alternator.
  9. Reinstall the serpentine belt and make sure that each pulley is correctly seated before mounting it. Refer to the illustration in the repair manual or on the sticker in the engine bay.
  10. Reconnect the battery’s negative terminal.

What Causes an Alternator to Overcharge?

The majority of the time, a faulty voltage regulator is the cause of an overcharging alternator. An alternator’s entire output of voltage is regulated by a voltage regulator, as its name suggests, preventing the generation of excessive output voltage.

Every alternator functions in combination with a voltage regulator made by the manufacturer, the majority of which are built inside the alternator itself. Typically, this regulator stops an alternator from producing charge rates greater than 13.5–14.5 volts. However, there is a relative decline in voltage regulation when this crucial component fails.

While voltage production-preventing alternator failures are more frequent, voltage regulator failures and the overcharging that frequently follows them do happen occasionally. A good digital multimeter is often used to diagnose this issue.

Can You Continue Driving?

It is never recommended to keep driving while your alternator is overcharging. Due to the electrolytes boiling over in this scenario, battery damage is very certainly going to result. Furthermore, operating a vehicle continuously above its authorized operating voltage can harm delicate electronics found in several control modules.

When an overcharging occurrence is severe, driving for extended periods of time can lead to expensive electrical system repairs that are significantly more expensive than changing the damaged alternator. The likelihood of such harm increases the longer a car is operated in this condition.

In any case, the underlying reason for a vehicle’s overcharging issue needs to be identified and fixed as soon as practical. This avoids a great deal of additional hassle and may lessen the need for costly secondary repairs.

Schedule a meeting with a reputable service shop as soon as you can if you do not feel confident handling such repairs yourself.

Frequently Asked Questions – Alternator Overcharging

Are 14.7 volts too high for an alternator?

Alternator output should be between 14.2 V and 14.5 V when measured directly across the battery posts in order for adequate charging times. Batteries have a significantly increased propensity to emit excessive amounts of acidic vapors and hydrogen gas, as well as to damage nearby objects when the charging voltage is higher than 14.5 volts.

Are 16 volts too high for an alternator?

It’s typical to see as little as 13 volts for some alternators. A reading of 13.6 volts that remains steady is problematic for certain people. Others frequently experience long periods of as much as 16 volts. Even so, it’s completely usual for other people to occasionally notice that the alternator isn’t even charging.

What can cause high voltage in a car?

Higher than 15 volts signifies a problem with the voltage regulator or associated circuits in the charging system. If it’s significantly too much, it can harm the battery or the electrical system.

How does a car act when the alternator is going out?

The gasoline injectors might not fire, resulting in an engine stall, if a defective alternator is unable to maintain a steady charge in your battery. A failing alternator can cause a variety of additional electrical problems. Generally speaking, these problems show themselves as a reduction in performance.

How do you know when you have a bad alternator or battery?

Re-start your vehicle. Your car’s alternator is probably incapable of recharging the battery if you can start the engine, but it shuts off quickly after. A dead battery, on the other hand, is most likely to blame if you re-start the automobile and it later struggles to start on its own.

Why is an alternator giving out 18 volts?

Your car’s electrical system will be damaged if the regulator malfunctions and the battery boils dry or explodes while charging at 18 volts. Before it is wrecked, get it towed to an automotive electrician.

What is the consequence of high voltage?

Circuit boards and other electrical & electronic components (such as those) can prematurely fail due to overheating when the voltage is too high. Overheating results in accumulated harm that cannot be undone.

What is the charge of an alternator when idle?

When the engine is idle, a decent alternator should generate 13.5 to 14.5 volts. Low voltage readings (12.5 volts or below) suggest a charging issue but do not provide any additional information.

Conclusion – Alternator Overcharging

Although alternator overcharging is a significant issue, it may be resolved in about an hour with the right socket set and a new alternator. If you can afford it, purchase a brand-new alternator or call the nearby restoration experts for an assessment.

A new alternator requires at least several hundred dollars in labor, but you can save money by purchasing the necessary tools and keeping them for future repairs. By doing this, you’ll gradually expand your toolkit to the point where almost all repairs only require replacement parts, sharply lowering the cost of ownership.

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