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Can a bad car battery cause an alternator to not charge?

Can a bad car battery cause an alternator to not charge?

In theory a car can run only with the alternator charge, but this can cause heavy voltage spikes and other strange symptoms so this means that a bad car battery can cause an alternator to not charge also. Cars are increasingly coming with modern electronics.

What causes an alternator to go over base voltage?

If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.

What happens when the alternator of a car is dead?

The alternator and the car’s battery work hand in hand. A good battery should give you service for the next five years before its lifespan ends. If your battery is dead, then it will not give power to the car’s alternator. The alternator normally lasts longer than the battery.

Why does my alternator not charge on tickover?

On checking the battery voltage was low – 11.8V engine running. Battery was replaced about 1 month ago.After much investigation discovered that the alternator does not ‘kick in’ until I rev the engine to approx. 3000rpm – it then charges away happly for the rest of the journey (at around 14.5V) even on tickover. Has anyone seen this problem before?

Why would a good alternator not charge a battery?

The alternator is powered by several different wiring mechanisms. If a wire is not attached properly, becomes detached or is inadvertently cut, the alternator will not have any power. If the alternator is not getting any power, it cannot turn the pulley and belt mechanism that charges the battery, and the battery will not charge.

Why isn’t my alternator charging my battery?

6 Causes of an Alternator Not Charging Worn out carbon brushes or damaged alternator. The most common reason why your car is not charging is actually because of a worn-out or damaged alternator. Broken Serpentine belt. Faulty fuse. Wiring issues or connectors. Damaged car battery. Engine control module error.

What are signs of needing a new alternator?

  • Warning Light. Many automobiles have a battery or alternator warning light on the dashboard.
  • Load Test. Conducting a load test will indicate whether or not your alternator needs to be replaced.
  • Voltmeter Test. You can test your charging system with a voltmeter.
  • Other Signs.

    What causes your alternator not to charge?

    There are several different problems that can cause your alternator to stop working. Your car’s alternator charges the battery by generating power with a pulley and belt system. If the belt that controls that system snaps, stretches out or breaks, the alternator will stop working, and the battery will not charge.

    What should I do if my alternator is not working?

    The solution is to check your car’s manual for the particular fuse that controls the alternator and replace it. In some cars, you might also find another small fuse to the alternator’s control—usually a 15A to 20A fuse. An alternator does usually has 3 or 4 wires to it to function properly.

    Why is there a noise coming from my alternator?

    Noise from the alternator could be caused by a faulty rotor shaft, rectifiers, bearings, slip rings, stator winding or brushes. You will need to carefully inspect each of these components and replace them. One sure way of confirming that the noise is coming specifically from the alternator is to use a vacuum hose.

    In theory a car can run only with the alternator charge, but this can cause heavy voltage spikes and other strange symptoms so this means that a bad car battery can cause an alternator to not charge also. Cars are increasingly coming with modern electronics.

    The alternator and the car’s battery work hand in hand. A good battery should give you service for the next five years before its lifespan ends. If your battery is dead, then it will not give power to the car’s alternator. The alternator normally lasts longer than the battery.

    The solution is to check your car’s manual for the particular fuse that controls the alternator and replace it. In some cars, you might also find another small fuse to the alternator’s control—usually a 15A to 20A fuse. An alternator does usually has 3 or 4 wires to it to function properly.

    Noise from the alternator could be caused by a faulty rotor shaft, rectifiers, bearings, slip rings, stator winding or brushes. You will need to carefully inspect each of these components and replace them. One sure way of confirming that the noise is coming specifically from the alternator is to use a vacuum hose.

    Can an alternator charge a deep cycle battery?

    If you have an inboard or I/O (inboard/outboard) engine, then you too are likely to have an alternator to charge your boat batteries. While an alternator is a good way to charge your boat batteries while on the water, there is a lot more to know about maintaining your marine batteries.

    Can a dead battery be revived by an alternator?

    Bear in mind here the distinction between a low charge, and a flat, dead battery. Yes – alternators can revive batteries that have drained somewhat, but they can’t revive a dead one (or at least it’s not recommended to try). When people say ‘flat battery’ they normally mean ‘low charge’.

    What should the voltage of an alternator be?

    Start your engine (up to 2000 RPM). Again taste the battery by running the engine in such away. If your battery is showing a reading in between 13 and 14 voltage that means your car alternator is fine. If you get a battery voltage less than this range, your alternator has some issues.

    Why is your new alternator not charging your battery?

    The most common reason for an alternator not charging a battery is because of a bad alternator or battery . You can easily test the voltage by connecting a voltmeter to your battery while the engine is off.

    Can a bad alternator overcharge a battery?

    Overcharging of the battery by a defective or malfunctioning alternator will result in the battery reaching an overcharged state. When overcharged, the plates inside the battery shed material and lose their capacity to hold electricity. The battery resists further charging, and the excess electrical charge builds up and is radiated as heat.

    Why does my car not start when the alternator is shut off?

    In this case, the alternator is doing its job of keeping the battery going once it has been jumped, but the battery can’t hold a charge when the alternator is shut off. A dead car battery is the first sign that something might be wrong with the alternator.

    Why does my car battery charge but not charge?

    Alternator problem occur because the alternator charges the battery when the car is running. If you jump the battery and it only remains charged for a little while, that’s a positive sign of a faulty alternator. However, it’s very important to have your car thoroughly inspected before you replace anything.

    In this case, the alternator is doing its job of keeping the battery going once it has been jumped, but the battery can’t hold a charge when the alternator is shut off. A dead car battery is the first sign that something might be wrong with the alternator.

    Alternator problem occur because the alternator charges the battery when the car is running. If you jump the battery and it only remains charged for a little while, that’s a positive sign of a faulty alternator. However, it’s very important to have your car thoroughly inspected before you replace anything.

    How long can a battery last without an alternator?

    A good alternator and can last well over a decade, sometimes as long as 15 to 20 years. However, if an alternator does fail on you then you’ll know it fairly quickly as your electrical systems will fail soon afterwards. The charge in your battery does not last long without the alternator there to keep it running properly.

    How can I tell if I have an alternator problem?

    To differentiate an alternator problem from the battery, you will need to use a voltmeter to check for voltage. First, turn off the engine and check the battery voltage. A fully charged battery should have a reading of 12.65 volts. Next, turn on the engine and recheck the voltage. You should have a reading of 13.5 to 14.5 volts.

    Why is my Camaro not in charge mode?

    Start the car and look at the multimeter reading. Because of the computer controlled nature of the Camaro’s charging system, it may not be in CHARGE MODE, just because the motor is running. To trick the system into charging, try turning on the headlight, and look for a voltage reading of 13.9 to 14.5 volts.

    Is the alternator the only thing that powers the car?

    Many people assume that the car’s battery is the only thing that powers all electrical components in the car. But, this is not true. The alternator plays a vital role in supplying power to the car’s AC, recharging the battery and ignition.

    What should my alternator voltage be when I start the car?

    To test the alternator, make sure the battery is charged and connect a multimeter to it, or the jump star post and a good ground under the hood. The multimeter should be reading at least 12.6 volts. Start the car and look at the multimeter reading.

    Why does the battery warning light come on after replacing the alternator?

    A relatively common “side-effect” of replacing a battery and/or alternator in a car is to have the voltage (battery) warning light come on. This is especially true in late-model vehicles with their more sophisticated internal diagnostic systems.

    Is it time to replace your alternator or battery?

    If so, it’s time to replace it. Some may recommend running the engine with the negative battery cable disconnected to test the alternator. However, this is not a good idea because it could damage the electrical system of your vehicle and cause greater problems. Fixing your battery or alternator can be an expensive repair.

    When does a car battery have a bad alternator?

    If your car engine shuts down immediately it starts or after a short drive, then your alternator has malfunctioned and is not charging the battery the way it should. If jumpstarting your car works and the car keeps running fine, but the vehicle does not start again using its power, then you have a dead battery on your hands.

    What should I do if my alternator keeps dying?

    The alternator is essentially a generator and it keeps your battery charged while supplying additional electrical power for the other systems in the vehicle. If you have a new alternator and your battery keeps dying on you, then there’s definitely a problem that you’re going to need to look into.

    How does an alternator and battery work together?

    Anything less than that and your car isn’t even able to start. Both of these car parts control your electrical system. However, your alternator charges your battery while your battery supplies power to your car. The failures of a battery are sudden, while failures of a failing alternator are slow.

    How long can a car go without an alternator?

    When you drive without a functioning alternator, your vehicle can only go for around Twenty-five miles before the battery is empty if you had a fully charged battery. Twenty-five miles translates to a maximum of approximately 30 minutes of driving.

    How can you tell if your car has a bad alternator?

    To find out more, review our article on signs of a bad alternator. When the engine is running, the alternator charges the battery, while also powering your car’s electrical system. The best way to find out whether your car needs a new alternator or a new battery is to test both components.

    What to do if your alternator is draining your battery?

    In summary, a faulty alternator can drain your vehicles ‘battery. To test whether an alternator is draining the battery, with the car’s engine switched off disconnect the car’s electrical system leaving the battery only.

    What happens when an alternator stops the motor?

    If you can’t get it to restart, this is a sign the alternator is doing its job of keeping the battery working while the motor is running, but the battery isn’t retaining the charge when the alternator has stopped. As batteries age, they become less able to retain a charge because the metal inside corrodes.

    How do I know if my battery or alternator is bad?

    Signs of a bad alternator. If the above steps reveal that the battery is working, it’s time to take a closer look at the alternator. There are certain signs of a bad alternator to look for: While running the car, note the brightness of the interior lights. If the dashboard gradually dims, the alternator is likely at fault.

    What are the signs of a weak car battery?

    Dim Headlights. Dim or weak headlight beams can often be a sign of a weak car battery if the battery lacks sufficient power to power the vehicle’s electrical accessories, including the headlights.

    How do I know if it’s the battery or the alternator?

    Check the Alternator. Test the alternator to make sure that it can start up the battery. If the battery is working properly and nothing is wrong with it, then it’s the alternator that will more likely cause a problem. Try to start the engine and listen carefully, if it produces a “whining” sound, it may be the alternator.

    Where is the charge wire on a Dodge alternator?

    There is a Black/Grey Wire between the Gen/Alt and the PDC which contains the 140amp fuse and then a red wire to the battery. This is the large charge wire that electricity flows from the Gen/Alt to the 140amp fuse in the PDC and onto the battery.

    What to do if your Dodge truck won’t charge?

    Quick Tip: If your 1st or 2nd Gen Dodge truck won’t charge, don’t waste your money on a new ECU. Try installing an external voltage regulator! Watch more Quick Tips: https://www.youtube.com/playlist?list… Follow Rich on Car Throttle. https://www.carthrottle.com/user/debo…

    Is the alternator at the heart of the charging system?

    Dan Ferrell writes about do-it-yourself car maintenance and repair. He has certifications in automation and control technology. The alternator is at the heart of the charging system of your vehicle. Alternator problems and charging system problems can affect your vehicle in different ways.

    Can a bad battery cause an alternator to over charge?

    Make sure that all the connections to the alternator, remote voltage regulator (if applicable) and battery are clean, tight and in good condition. Check your battery or have it tested at your local auto parts store. A bad battery cell can cause the alternator to over-charge the good battery cells.

    Why is the alternator on my Dodge Ram not charging?

    The 2nd gen had external regulators, 3rd gen they went to the PCM. My 3rd gen had a fluctuating voltage issue i only notice when i installed a jl audio amp and it would shut off if it went over 15v. I ended up installing an external vr and just had to deal with the ck gauge light. Brandon-w likes this.

    Dan Ferrell writes about do-it-yourself car maintenance and repair. He has certifications in automation and control technology. The alternator is at the heart of the charging system of your vehicle. Alternator problems and charging system problems can affect your vehicle in different ways.

    Why is my car battery still not charging?

    If you are sure that your alternator is working properly and yet your battery is still not charging, then it’s possible that you have a bad voltage regulator in your vehicle. The voltage regulator keeps the right amount of electrical power flowing through the various electrical systems in your vehicle.

    How does the battery and alternator work together?

    The battery, on the other hand, supplies electrical energy to your car when the engine is off. Also, the battery provides the current needed to energize the starter, which then cranks the engine to get it running. Once everything is in motion, the alternator takes over supplying power to the car’s onboard electronics.

    What does it mean when your alternator stops the car?

    If you can’t get it to restart, this is a sign the alternator is doing its job of keeping the battery working while the motor is running, but the battery isn’t retaining the charge when the alternator has stopped. The car battery could be old. As batteries age, they become less able to retain a charge because the metal inside corrodes.

    When to know if your alternator or battery is bad?

    Using the process of elimination, find the culprit by bypassing the battery’s role and jump-starting your car. If the engine starts but dies immediately, your alternator probably isn’t keeping your battery charged. If a jump starts and keeps your car running, but the car can’t start again off of its own power, a dead battery is likely your answer.

    Where can I buy an alternator for my car?

    Car parts are normally listed in the automotive section of the want ads. Craigslist is another good source of car parts. People parting out vehicles often sell the parts online and if you know what you’re looking for, bargains can be found. Auto parts stores often sell second hand or rebuilt car parts, including alternators.

    To differentiate an alternator problem from the battery, you will need to use a voltmeter to check for voltage. First, turn off the engine and check the battery voltage. A fully charged battery should have a reading of 12.65 volts. Next, turn on the engine and recheck the voltage. You should have a reading of 13.5 to 14.5 volts.

    What happens when the belt on an alternator breaks?

    A closer observation of the alternator will reveal a pulley and belt system that works to convert mechanical energy into electrical energy. The serpentine belt powers the alternator, and if it fails, the alternator will stop working the moment your belt wears out and breaks, or the pulley becomes damaged.

    Is there a problem with the alternator in Liberty?

    Discussion in ‘ Liberty ‘ started by jonahb1987, Jul 10, 2019 . I recently had a breakdown. At first we thought it was the alternator, so I bought a new one. Had it installed at a mechanic and the same problem would happen. After being jumped, it would start but putter out in like 4 minutes.

    What to do if your alternator won’t charge your battery?

    Make sure you ground your multimeter, and put the power side to the stud that is coming out from the alternator (should be nut holding your wires that go to your battery). If your getting 13.5-14.5V there then the connection between the alternator, and battery is bad.

    What causes an alternator to stop working on a car?

    Once the alternator stops working, so do all of the electrical systems required to keep a car going. Other problems can also cause a car to not start. It could be a bad starter, corroded cables, or a broken connection somewhere between the battery and starter.

    A good alternator and can last well over a decade, sometimes as long as 15 to 20 years. However, if an alternator does fail on you then you’ll know it fairly quickly as your electrical systems will fail soon afterwards. The charge in your battery does not last long without the alternator there to keep it running properly.

    Why is my Honda alternator not charging the battery?

    I was in the process of limping it home when I realized that the alternator was not charging the battery (pulled the negative cable off the battery and the van died). No bid deal, Im a mechanic so I went to Advance Auto Parts and got a replacement alternator. Put it on, charge the battery and problem solved for a while.

    How can I tell if my alternator is charging the battery?

    Use your multimeter (if you don’t have one get one). Turn it to dc volts put your leads on your battery (with the car running), if your alternator is charging it should read from 13.5V-14.5V (thats a good charge). If your not getting a reading from there you can check your output from your alternator.

    Can you drive a car with a faulty alternator?

    Faulty diodes can easily be replaced, but you will need to dismantle the alternator. It is impossible to drive the car with a faulty alternator. While it is the work of the battery to power the electrical components in the car, it cannot do this alone.

    How long does a car battery last without an alternator?

    If you are lucky and could get up to two hours. Note: In case you have to start the car without an alternator, don’t turn off the engine once you’re going. Starting the car flattens the battery down quickly. Starting a car uses ten times more juice than everything else put together.

    Why is my Ford F-150 not charging?

    Please try again later. On many Fords the alternator has a ‘smart charge system’ that regulates the output of the alternator to ensure the battery is being charged efficiently, reducing emissions and improving performance. So let’s come along with Eric O. at the SMA shop as he diagnoses this F-150 that came in with a no charge condition.

    Many people assume that the car’s battery is the only thing that powers all electrical components in the car. But, this is not true. The alternator plays a vital role in supplying power to the car’s AC, recharging the battery and ignition.

    How does a lithium battery affect an alternator?

    Since lithium batteries have such a low resistance, the lithium battery will take all the charge current the alternator can deliver. This causes the alternator to deliver the max charge current until the battery is fully charged.

    Can a bad alternator damage a battery?

    For one, a bad alternator can kill a battery, even if it was not the battery that was the issue to start with. When the alternator is going bad, the battery picks up the slack of providing electricity to the car’s electrical system.

    What causes an alternator to go bad?

    Reasons an Alternator Would Go Bad Failing Diodes. An alternator is essentially composed of three smaller alternators that each supply varying levels of power. Defective Bearings. Alternators revolve on high-precision needle bearings that you generally cannot hear. Insufficient Field Voltage. An alternator must have a field voltage of 12 volts to produce electricity. Worn Belt.

    A relatively common “side-effect” of replacing a battery and/or alternator in a car is to have the voltage (battery) warning light come on. This is especially true in late-model vehicles with their more sophisticated internal diagnostic systems.

    Why does my Roadtrek battery not boil over?

    These batteries will not boil over because there is no water inside. If overcharged, a wet cell battery can boil – if there is not a special circuit to prevent this. The two AGM batteries that Roadtrek is using now have 220 amp hours. I will explain this more later.

    What happens if you put a wrong battery in your car?

    Installing an incorrect battery can adversely affect the electrical system of your vehicle, and cause major damage if the terminal locations create a short circuit with nearby components. If you are unsure about which battery to buy, ask your car mechanic or consult the vehicle owner’s manual.

    Where is the battery disconnect switch on a Roadtrek?

    FOR YOUR BATTERIES TO WORK YOUR BATTERY DISCONNECT SWITCH MUST BE ON! The battery disconnect switch is located on the bottom right of the monitor panel. Here is a photo of mine. See the rocker switch on the right. It says “BATTERY” next to it.

    What kind of battery do I need for a 2002 Ford Think?

    Most everyone on this forum would likely recommend that you upgrade the battery pack to some sort of lithium cell rather than use the old-school technology of lead-acid. I have recently purchased a 2002 Ford Think.

    What to do if your Ford battery is toast?

    Well that’s a sad story–shame on the seller for not being honest with you, they had to know that the batteries were toast. Most everyone on this forum would likely recommend that you upgrade the battery pack to some sort of lithium cell rather than use the old-school technology of lead-acid.

    Is there a case of a Ford battery depleting itself?

    It contained this sentence: “Ford, however, found that there has never been a case of the main battery depleting itself so far that it couldn’t fire up the gasoline engine, even after freezing the vehicle for two days at minus 30 C in Alaska.” In other words, color us skeptical about what the dealer told her.

    How long does it take to charge a Ford Think battery?

    It was plugged in for three full days, full charge showing on both the on board charger and dash meter….it will go about 8 feet and they are completely drained. New battery time. I would like to replace them with no maintenance, sealed 12 V batteries.

    Can a loose tensioner cause an alternator to fail?

    Nevertheless, if the tensioner wears out, it can cause alternator problems (loose belt or worse, the belt can totally fall of the alternator pulley). Broken or damaged wires This happens mostly in older cars duo to material fatigue of the electric installation.

    What causes an alternator pulley not to work?

    Not replacing it on time, stuck alternator pulley or a faulty bearing are common causes of this problem. Worst thing about this problems is that it can snap at a moments notice. Main causes of alternator problems (at least from what I’ve seen) are: This is the first and most common reason of them all.

    What happens to the spark plugs when an alternator goes bad?

    The alternator in your car provides power to the spark plugs that ignite the gas in your engine. If your alternator is beginning to go bad there might not be enough power in your spark plugs to start your car or keep your car running.

    Can a bad battery cause an alternator to fail?

    The alternator is responsible for recharging your car’s battery. Car batteries can (and do) fail on their own. However, a bad alternator can cause your car battery to drain and not be recharged. If you find yourself jumpstarting your car frequently or your battery dies, be sure to have your alternator checked.

    Can a bad alternator cause an engine Rattle?

    This seems like a vague symptom–after all, lots of things can cause unusual noises in the car. However, sometimes alternator failure can cause some of the bearings to fail in the engine, creating unusual rattles. The alternator might be the culprit, especially if accompanied by some of the other symptoms we’ve mentioned.

    What to do when you install a new alternator?

    When a new alternator is installed, check the battery voltage and use a battery charger to bring the battery up to full charge before you return the vehicle to your customer. Also, start the engine and use your DVOM to check the charging output of the alternator. Don’t assume everything is working OK just because you bolted in a new alternator.

    When to replace the alternator on a Ford 4.6L?

    Now, this test result, in conjunction with ALTERNATOR TEST 1 and 2, let’s you now that the alternator on your Ford 4.6L or 5.4L is equipped car, pick up or SUV is bad. Replace the alternator. Replacing the alternator will solve the No Charge condition on your vehicle. CASE 2: The fuse IS blown.

    A closer observation of the alternator will reveal a pulley and belt system that works to convert mechanical energy into electrical energy. The serpentine belt powers the alternator, and if it fails, the alternator will stop working the moment your belt wears out and breaks, or the pulley becomes damaged.

    If you can’t get it to restart, this is a sign the alternator is doing its job of keeping the battery working while the motor is running, but the battery isn’t retaining the charge when the alternator has stopped. The car battery could be old. As batteries age, they become less able to retain a charge because the metal inside corrodes.

    How does an alternator start and run an engine?

    Starting and running an engine, in its simplest form, is a three-step process. First, the battery delivers a jolt of electricity to the starter. This starts the engine running, which puts the alternator into action. Finally, the alternator completes this cycle by charging the battery.

    The battery, on the other hand, supplies electrical energy to your car when the engine is off. Also, the battery provides the current needed to energize the starter, which then cranks the engine to get it running. Once everything is in motion, the alternator takes over supplying power to the car’s onboard electronics.

    Start your engine (up to 2000 RPM). Again taste the battery by running the engine in such away. If your battery is showing a reading in between 13 and 14 voltage that means your car alternator is fine. If you get a battery voltage less than this range, your alternator has some issues.

    The alternator is essentially a generator and it keeps your battery charged while supplying additional electrical power for the other systems in the vehicle. If you have a new alternator and your battery keeps dying on you, then there’s definitely a problem that you’re going to need to look into.

    Can a weak battery destroy an alternator?

    A weak battery can adversely affect your alternator in the long run. Imagine a scenario where your car broke down and won’t start. You have a busy day ahead of you but you’re a car guy and your vehicle is a priority to you.

    How many volts should my alternator be charging at?

    A car alternator needs to be putting out at least 13-14 volts (ideally between 13.8 and 14.2 volts) to effectively charge a 12 volt car battery. If the alternator is putting out too much voltage (15+ volts), it is likely your battery acid will boil over out of the battery.

    What are the symptoms of a bad alternator in a GMC Sierra?

    Here are the most common symptoms of a bad alternator in a GMC Sierra: The battery light is designed to tell you that there is not enough voltage to properly charge the battery, or that the battery itself is not holding the proper voltage. In rare occasions the service engine soon light may light up.

    What does it mean when your alternator is not charging?

    If the alternator is not charging the battery, you will have a red “ALT” or “charge” sign on your dashboard. This means that your battery is no longer being supplemented for power by the alternator. You will need to recheck the wiring because the light could also be faulty.

    Will alternator cause no start?

    Charging Problems. The first sign of trouble when an alternator is failing is a low or dead battery. On a late-model vehicle, that can not only cause a no-start but also can cause the loss of “learned” data in the powertrain control module and other modules throughout the vehicle.

    Can bad alternator drain battery?

    If your alternator has a bad diode , your battery can drain. The bad alternator diode can cause the circuit to charge even when the engine is shut off, and you end up in the morning with a car that won’t start.

    Can a bad alternator leave a Chevy Silverado without power?

    A bad alternator can leave your Chevy Silverado without power and unable to move. Alternators don’t always go bad in the exact same way. We’ll cover the symptoms of when an alternator goes bad, and how to diagnose a bad one (which is really pretty easy).

    What are the symptoms of a bad alternator?

    In rare occasions the service engine soon light may light up. Also, some vehicles have an “alt” light that specifically tells you there is a problem with the charging system, and not the battery itself. Outside of the battery warning light, a dead battery is the most common symptom of a bad alternator.

    Do you need an alternator for a 12 volt car?

    If you got 14.2 or more volts, the alternator is charging fine. If it’s still showing in the 12’s, it’s time to replace the alternator. If it’s producing a voltage level in the 13’s, go ahead and take it into a parts store and have it tested. It’s probably bad.

    What causes an alternator to over charge a battery?

    Measure voltage across the battery with your DMM. You should get 0.5 to 2 volts higher than base voltage. If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.

    What should the voltage be on a GM Charger?

    The system voltage is below 12.56 V When any one of these conditions are met, the system will set targeted alternator output voltage to 13.9-15.5 V, depending on the battery state of charge and estimated battery temperature.

    What should alternator voltage be on Silverado Sierra?

    Did you check it on the battery terminals or the alternator terminals? 13.8 and 13.9 are normal. 14.0 -14.8 is normal. Crank the truck make sure everything is off (ac, heater, radio) and test the alternator straight from the alternator terminals you should get in the 14 area.

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Ruth Doyle