Battery light on; belt noise

The battery light is on. I think the battery is not charging. And there is a belt noise when starting the car. I think it's either a loose belt or the alternator seized or is bad.
Experienced mechanics share their insights in answering this question :
When the Battery Light on the dashboard illuminates, usually there is an issue with the alternators performance. The alternator is the device that maintains the batteries charge during vehicle use. If the belt is too loose, it can slip causing noise. Also, a slipping belt cannot spin the alternator properly and causes it to appear to be malfunctioning when the belt just isn’t tight enough. Have an experienced technician inspect the drive belt system and test the vehicle’s battery in order to make the necessary repairs.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

The battery light is an indication that something in your charging system is not working properly such as a weak battery (usually noticeable with a weak start), a failing alternator or a bad voltage regulator. The whining sound may be the alternator failing which is common when this happens.
Basically, the light indicates a battery charging problem. If the light comes on and stays on while driving, this means that your alternator is running solely on energy stored in the battery. If you continue driving, your battery will eventually drain and your vehicle will stop working.
A failing alternator belt can cause the Battery Light to turn on, dimming or flickering lights in the car, and engine stalls.
The belt squeals because there is improper tension in the belt drive system. This is usually caused by a worn automatic tensioner, but other causes can include a contaminated belt (oil, belt dressing, etc.) or a belt that is too long or worn out.
If you ever hear growling or whining noises coming from under the hood, you could have alternator problems, which should be checked out by a professional ASAP. This growling or whining sound happens when the belt that turns the alternator`s pulley becomes misaligned or rubs against the side of the pulley.
An effective method to determine whether it`s your battery or alternator that`s gone bad is to connect jumper cables from a running vehicle`s battery to yours. After a few moments, try starting your vehicle. Once it`s started, remove the jumper cables — if your engine stalls, your alternator has probably gone bad.
Probably, the most common symptom associated with a bad regulator is flickering, dimming, or pulsing lights. To be more specific, you may notice that the vehicle`s: Headlights fluctuate between bright and dim, without you doing anything. High beam isn`t working as expected.
One of the most common signs that your car`s serpentine belt is going bad is squealing noises coming from the engine. The belt may be loose and need to be tightened, or it could be worn out and need to be replaced. If you hear squealing noises, it`s best to take your car to a mechanic to have it checked out.
Misaligned pulleys usually cause belt noise at idle that gradually goes away with increased engine speed. Sometimes belts will make noise when the humidity is high, then quiet down on dry days. This is particularly true if the belt tension is weak, allowing the belt to slip.
It is recommended to have a dedicated grease gun for alternator bearing re-lubrication only. Never mix lubricant types. As per the Installation, Service & Maintenance manuals, it is vital that the grease, grease gun, grease nozzle and relubrication nipple are free from abrasive materials and other contaminants.
Signs of a Bad Alternator

Some of the things to look for are no-starting and trouble starting, dimming lights and problems with stereo system output. If your car starts but stalls when you`re underway, your battery is probably not being recharged due to a faulty alternator.

Can I Still Operate My Vehicle with a Bad Alternator? While you can technically still drive with a bad alternator, it is not advised. This is especially true in newer vehicle models. This is because there is more electricity involved compared to an older model.
If engine noise is your culprit, you may hear a whining or clicking sound. Its pitch will usually vary with engine speed. If this is the case, you can install an alternator noise filter on the power line between the battery and the alternator to minimize the problem.
Battery Problems

Low pitched whining noises and the noise of a cranking engine without it starting are both signs of a dead battery. No noises at all are also a sign of a flat battery. Check for any visible signs as well, such as the battery warning light illuminating.

If engine noise is your culprit, you may hear a whining or clicking sound. Its pitch will usually vary with engine speed. If this is the case, you can install an alternator noise filter on the power line between the battery and the alternator to minimize the problem.
A bad battery won`t damage the alternator, but a bad alternator can damage a battery. The car battery simply isn`t made to deliver electrical energy for extended periods, so both components need to be functioning optimally.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

in my car battery warning light appearing while driving.so I have replaced both battery and alternater still light is on
ANSWER : As you may yourself have seen, there are many reports of this fault with the Civic, that is a battery or alternator is replaced only to have the warning light fail to extinguish despite checking every conceivable electrical possibility. Your only recourse is to have a certified mechanic go through that exercise with your car and that involves first attempting to "re-set" the light. If the warning light returns, the alternator output has to be carefully measured both loaded and unloaded. All terminal connections have to be verified including all grounds. Fuses have to be checked for integrity (continuity) and the possibility of shorts, in for example dash wiring, has to be checked. To request this repair, simply request an electrical components diagnostic and the responding certified mechanic will seek a resolution to this.

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The Battery Light is on and the lights and power mirrors are not working – 2002 Mercedes-Benz C320
ANSWER : Hi. If the Battery Light is on, this an indication that either the battery is bad, the alternator is not charging properly, or both of them are bad. Low battery voltage will cause the car to do abnormal things like have no headlights. There are other things that can cause headlights to not work as well, for example, a blown fuse, broken headlight relay, or, the most common cause, blown headlight bulbs.

I suggest you have a certified technician, such as one from YourMechanic, come to your location to determine why the Battery Light is on and suggest the necessary repairs.

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I have Chrysler 300c. Battery light came on, changed battery and alternator but power still getting drained and battery light still comes on.
ANSWER : Hi, thanks for writing in. This may be a sign of a failing starter relay. The starter relay is a small unit near the starter that directs power to the starter from the battery. When this fails, it may cause a clicking sound and will not allow the starter to engage the flywheel when you turn the key. I would suggest having a professional from YourMechanic come to your home to diagnose your starting issue to determine the solution to get you back on the road.

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Abs light, emergency brake light, steering wheel assist light, engine light, EPC light, traction control light
ANSWER : Hello, thank you for writing in. The vehicle does utilize a lot of the same sensors for these systems. Are there any other codes that are coming up when this code appears? If so you will want to take these into consideration when processing the repair and making a diagnosis. The module may be bad, and replacing it should fix the problem. The lights should turn off once the main computer recognizes the new module and the sensors sync up. If you believe the sensors need to be cleaned you may do so. Do as minimal as possible to make sure you are not damaging the sensor or disrupting the wiring inside. A bad connection would make the lights stay on. With so many lights that are effected by the module being illuminated, the module is likely bad or does not have a connection. Check the connection first and then resort to replacing the unit. For more help with these electrical tests, contact our service department.

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Car battery light is on replaced alternator battery and starter and battery light is still on.
ANSWER : You may have a failing voltage regulator that could be allowing the alternator to supply too much or too little amperage to the battery resulting in the battery never maintaining a consistent charge as it is designed to. The voltage regulator is a unit that regulates the charging of the battery by the alternator. When the voltage regulator is not working properly, this may result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. A common sign of this is usually the acid inside the battery boiling causing the battery to swell. You may also smell a bit of smoke due to things potentially getting too hot. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle’s charging system.

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Battery light came on went and bought a new battery battery light comes on about 1 minute after starting car.
ANSWER : The alternator on this vehicle is computer controlled and if the alternator is not communicating to the computer then it may default to a set charging rate that will show up as good when testing using standard methods. The computer and charging system needs to be tested using a scanner that is compatible that can check and test charging rates. You most likely do have a bad alternator on the car.

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My battery light came on when i was briving and so did some other lights on the dash board replaced battery and it still came on w
ANSWER : Hi there. What you are describing is common with an alternator failure or problems with the charging system in your Chrysler. The battery is supposed to supply power to the vehicle before starting the car, in which time the alternator takes over. If the alternator is damaged, the car will continue running off the battery and drain it. This is what tends to cause the clicking issue when you turn the key. It is probably a good idea to verify this problem before attempting repairs, by having a professional mobile mechanic come to your location and complete a battery will not hold a charge inspection.

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Battery light goes on when I start car then turns off, if I rev engine light comes back until rpms go down. Abs goes comes on/off
ANSWER : Batteries can die due to faults in the charging system so ideally a suspected "faulty" battery should be load tested before a decision is made to condemn it. The only exception to this rule is if the battery is already clearly "old" (greater than 5 years) but even then once you put a new battery in, as a replacement for a "dead" battery, you have to comprehensively check out the charging system. Diagnostic Trouble Code P0460 will result in disruption of the dashboard fuel gauge’s ability to accurately report your tank’s fuel levels. The fuel gauge readings may be erratic, or read somewhere off scale. Vehicles equipped with a low fuel warning light feature may also suffer from erratic low fuel warnings in the event of a code P0460. Unless the P0460 code has been reported alongside other trouble code, all of the vehicle’s essential systems should otherwise function normally. I would recommend that you request a check engine light diagnostic to first resolve the fault causing the P0460 code to set. The check gas cap light warning light could be due a faulty gas cap and/or small leaks in the EVAP system.

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