Driver's Guide

Why is My Car Battery not Charging?

Howdy, Driver? Why is my car battery not charging? Your car battery is not charging due to a couple of reasons that may include but is not limited to a blown fuse, faulty alternator, ECU error, damaged fan belt, and battery terminal corrosion.

why is my car battery not charging

Your car battery is not charging because you either parked the car for too long, or the terminals have corroded. It could also be that your ECU is faulty.

It’s annoying when you figure out that your car battery won’t charge at all. Certainly, car batteries are supposed to be powered while driving.

Since yours isn’t, there is a problem. What if the battery is already damaged? Yes, there is that tendency that your car battery is old and faulty. Replacing the battery will, of course, fix the problem.

Nonetheless, if the issue does not lie with the battery being faulty, the problem will persist even after battery replacement.

It will hurt to get a brand new battery with the same problem of “battery nor charging” bugging your mind. Don’t let a bad car battery cause overheating. Let’s find out more possible fixes you may have to put in place before concluding that the battery is faulty.

Why Is My Car Battery Not Charging?

Your car battery is not charging? Below are the reasons why your car battery is not charging:

  1. Battery Drainage from Lights or Third-Party Devices

car battery will not hold charge

Battery drainage is another possible reason why your car battery is not charging. The culprit behind why the battery drains could be tough to figure out.

Nevertheless, a thorough inspection should help figure out what the cause is. Meanwhile, the basic things to look out for include the following:

  • Check whether the hood light turns off when the hood is closed.
  • Confirm that the headlight is fully off when the car is turned off.
  • Look out for the trunk light when the car is in an off state.
  • Turn off the car, close the door, and confirm whether the glove box lights turn off.

If any of the above-mentioned lights remain on, that’s the culprit. While the car is turned off, the headlight may remain on but with dim lighting.

It prevents the car battery from sleeping and causes battery drainage. Third-party devices can prevent the car battery from sleeping. Confirm that no third-party device like Bluetooth and others are disabled alongside the car.

  1. Blown Fuse

why is my car battery not charging

Another possible answer to the question, “why is my car battery not charging?” is a blown fuse. As the car ages, the fuse becomes more susceptible and weak. Powering the engine will be a burden on a weak fuse and the reason why the car battery won’t charge at all.

If you do not know where to locate the fuse in your vehicle, open the engine hood and refer to the car manual for clarification on individual fuses.

Search for the fuse box and open it with a screwdriver. Inspect fuses to see if they are in good condition. If not, the fuses are okay.

  1. Damaged Fan Belt

why is car battery not holding charge

Concerning the question, “why is my car battery not charging?”, a damaged fan belt could still be the problem. Over time, the fan belt also called serpentine belt becomes loose or wears down abruptly.

It is unable to drive the alternator belt which makes starting your vehicle difficult. In extreme cases, it kills the battery which is why the car battery won’t charge at all.

The simple way to diagnose this is to inspect the fan belt for possible damage. If you find the fan belt or serpentine belt to be faulty, contact your mechanic for immediate replacement.

  1. Loosed or Corroded Battery Terminals

car battery not charging

If you have an older vehicle, it is easier to access the terminals. As time goes, the terminals of car batteries tend to corrode or become loose. A simple fix for this issue is to clean up the affected terminals using a not-too hard brush, sandpaper, or any nearby alternative.

This process may be a bit demanding on modern cars which require a few disconnecting a few plastics and caps. If you do not know the appropriate process involved, refer to the car manual for further instructions.

  1. Defective Alternator

why won't car battery charge

It is also possible that the alternator of your car has gone bad. If you have been fond of jump-starting the car, the chances are that the alternator is faulty and should be fixed. What happens when the alternator is bad includes the following:

  • Dim headlight
  • Charging system warning
  • Car not starting
  1. ECU Error

how to fix car battery not charging

According to Champion Auto Parts, ECU is a possible cause of car battery not charging. ECU is an acronym for the ‘Engine Control Unit’. Most car designs are based on ECU which controls and commands the systems that run the vehicle.

If there is a coding error, it may likely affect the car battery, thus, preventing it from charging.

The best option out of this mess is to run an ECU diagnosis using a diagnostic scanner. A mechanic would be the best bet for it since they know the right signals.

  1. Damaged Battery

New car battery not charging

A bad battery could be the answer to the question, “why is my car battery not charging?” Car batteries have an estimated lifespan of 5 years. It can be higher or lesser depending on the climate or how often you drive.

A simple method to tell if the car battery is faulty is starting the car with the battery of another vehicle. This process is called ‘jump-starting’ and you should allow the battery to charge for a while. When you disconnect the jumper cables and your car goes off, the car battery is the culprit.

Now that we have the battery as number one suspect, go on and disable the headlight and other components of the car that depends on the battery.

You can remove the vehicle from ignition to close most of the running functions. This should further help to determine whether the car battery is faulty.

If your car is giving you a headache, how about scraping it for the most money even without a title?


How Do You Know if Its Battery or Alternator?

It’s easy to know whether the alternator is faulty. Simply, unplug the positive connection or terminal and watch whether the car ceases.

If it does, the alternator is faulty. Extensively, turn off the engine and get a voltmeter set to direct current.

Connect positive lead to the positive battery terminal and negative lead to the negative battery terminal. If the voltmeter reads less than 12.5 volts, plus or minus 0.2 volts, chances are that the alternator is the problem.

Car Won’t Start but Battery is Good – Why?

Your car has an ignition problem and could be that the ignition switch is faulty. To be sure that the battery is not the culprit, try to put on the headlight. If the headlight light goes on, the battery is okay.

Moreover, it could be that either the fan belt or alternator is faulty. ECU error can also be the reason why a good car battery won’t start. If after initiating these fixes, the car won’t start, a fuse is broken.

How Do You Fix a Car Battery that Won’t Charge

  • Get the battery ready.
  • Load tests the car by connecting the positive and negative load testers to the battery terminal.
  • Gently loosen the cell cap.
  • Carry out a hydrometer test using the hydrometer to squeeze the bulb and place the tube in the battery cell. Repeat this for all cells and take note of the color each cell rises to.
  • Test each cell using a voltmeter by placing positive voltmeter cables on the positive terminal and negative on the negative terminal. Repeat this stage for all and ensure that each cell reads at least 2 volts.
  • If you have treatment chemicals around, apply to each cell for correction. From here, you may follow the user manual provided by your manufacturer in pouring in the chemicals to each cell.

This is how to fix a car battery not charging on your own. Nevertheless, it’s recommended that you contact a mechanic for a better job and to avoid further damage to the car battery.

Note: If you encounter a dark color solution during the hydrometer test, the battery is bad and should be replaced.

Why Will Car Battery not Hold Charge

The obvious reason is that the car battery is old and too weak to hold the juice. Extensively, there could be possible corrosion on the battery terminals which must be brushed.

So, if your car battery is new and won’t hold a charge, the problem is likely to be caused by corroded terminals. Moreover, if the car has been parked for days without even an ignition, the juice has drained and may require a simple jump-starting to be resuscitated.

Concerning how to fix a car battery that doesn’t hold a charge, you may have to replace the battery if it’s old. If the issue does not lie with battery age, check battery terminals for possible corrosion.

New Car Battery Won’t Start Just Clicks – Why?

The starter motor hasn’t enough battery juice to power the engine. There may be terminal corrosion or poor connection in battery terminals. It could be that the cables are faulty and need replacement. First, check the battery terminal for a corroded connection and brush it off. Also, inspect the cables for damages.

Final Thought

This article is not a DIY guide but a resource exposing you to the possible reasons why your car battery isn’t charging.

A further answer to why your car battery is not charging would be answered after a professional diagnosis from a mechanic.

Are you tired of the car already? Consider doing any of these with the old car.

Latest posts by Bernard Juchli (see all)

Bernard Juchli

Bernard Juchli is an experienced racer, mechanic and team owner who trusts Avon Tyres.Bernard is the lead driver and force behind his Big Dog Garage Race Team. He is the General Manager and Chief Mechanic of Jay Leno’s Garage. Bernard and his crew of seven are responsible for all repairs, restoration and fabrication of Jay’s incredible automobile and motorcycle collection.

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