Battery not holding charge

My battery won't hold a charge.
Experienced mechanics share their insights in answering this question :
Hi. Inside a 12 volt battery there are 6 cells and each cell has a number of plates in it. These plates are suspended in acid which starts the chemical reaction that produces voltage across the terminals of the battery. Through the battery’s life, deposits form as material is transferred between the plates. If the deposits from one plate touch another, it shorts out the battery, effectively making the battery lose its charging ability. I would recommend you have a mechanic, like one from YourMechanic, inspect the battery on your vehicle and replace any damaged parts.

How to Identify and Fix Common car Problems ?

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This can be caused by overcharging, undercharging, or leaving the battery in a discharged state for too long. A battery that doesn`t hold a charge is frustrating and can happen for many reasons. It could be an issue with the batteries themselves or a problem with the charging system.
It`s easy: mix and dissolve Epsom salt and distilled water in the proportion 1/3. The issue can be resolved by adding the solution to the battery cells at the battery terminal until the plates are covered by 1/4 to 1/2.
What may drain a car battery when it`s off are things such as interior lights, door lights, or even bad relays. While your engine runs, the alternator recharges the battery — which is why you typically don`t have to worry about the battery dying while you`re blasting the radio on your drive to work!
Why Your Car Battery Keeps Dying. While car batteries slowly die over time, high heat, brutal cold, excessive use of vehicle accessories (after-market equipment), and other mechanical issues can shorten the life of even the toughest battery.
One of the most common reasons the battery light comes on and the car battery stops charging is because of corrosion. Whether the corrosion is on the battery cables or cable terminals, it is still a problem that needs to be addressed. Another common culprit for the battery not charging is a problem with the alternator.
A healthy 12 volt battery should maintain a voltage range from 9.6 – 10.5 volts under the load for a good 30 seconds straight.
In some cases, the battery can just be recharged. This is often true if you accidentally left the lights on and the battery died. Give it a jump and it should be back to normal. However, if the battery is getting old and just not performing like it used to, it is probably time to get it replaced.
Attach a battery trickle charger or a computerized smart charger to your old lead acid battery, and allow charging continuously for about a week to 10 days. The extremely slow charging rates dissolve the de-sulphation that kills the battery, and revives it back to being able to hold a usable charge.
Baking soda neutralizes the battery acid, and a little vinegar (or lemon juice) reacts with the baking soda to break it down. Here`s everything you`ll need to remove corrosion in the battery compartment: White vinegar or lemon juice.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

installed new alternator and battery the alternator is charging the battery and the battery is maintaining afull charge but the ba
ANSWER : Hello. If the battery and the alternator are new and if it is verified that the alternator is charging then you have an issue with programming. When you replace the battery on this vehicle the computer needs to be reprogrammed to recognize it and to properly charge it. If this is not done then the computer will not turn on the alternator at the correct times an this battery light will come on. You need to have this programming done by a certified mechanic, like one from YourMechanic, who can come to you to [program the battery into the computer]

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New battery won’t hold a charge. 2000 Ford Ranger
ANSWER : Hi there – this behavior sounds more like there is a parasitic load, or drain, on the battery after shutting it off. This problem can be diagnosed by connecting an ammeter to the positive (red) battery cable, observe the current drain (likely less than 1 amp), then, one at a time, remove each fuse, check to see if the current drain has dropped to near 0, then reinsert the fuse. This process should identify the faulty circuit in most cases. The specific components on that circuit can then be checked for current drain problems. A professional mechanic, like YourMechanic, can come to your location, and perform this procedure for you, and replace/repair the failing component.

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A new battery will not hold charge overnight. alternator is not the problem / 2 mechanics checked.
ANSWER : Hello. If the battery continues to drain overnight despite recent replacement, then there might be some sort of electrical short or malfunction somewhere on the vehicle that is draining the battery. A good battery should hold a charge overnight without any issue. A simple load test should be able to determine if the battery is good or not.

There is also the possibility that you may have the incorrect battery. Your vehicle uses a 4.6L V8, and has a considerable amount of electronic accessories, and will experience all sorts of issues if the incorrect battery is used. I would verify that the battery is the correct size, and able to hold a charge, and then move on to examining the possibility of an electrical short. If you need further assistance with this, a certified technician from YourMechanic can inspect the battery firsthand to pinpoint the problem and make appropriate repairs.

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Battery dead truck wont start after alarm being messed with.
ANSWER : With all the playing around, the battery going dead more than once, and it being over 5 years old, I would try replacing the battery first.

After the battery is replaced, lock all the doors and then unlock the vehicle with a remote or door keypad if you have one equipped. Next, using an original key, see if it will start. If it doesn’t then the vehicle may have locked you out. In this case, only a WDS scan tester at a dealer can regain access to the passive anti-theft system for you. Unfortunately this would mean that you’ll need to tow it to a dealer.

If you decide to get this fixed or would like a second opinion on this, get the car looked at by a qualified technician, such as one from YourMechanic. A mechanic can perform these checks to properly diagnose your dead battery and fix it accordingly.

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Battery is not charging properly
ANSWER : Hi There,
What you are describing is most likely a faulty alternator. The alternator charges the battery while the engine runs by generating amperage and recharging the battery while the engine turns the alternator pulley. The voltage regulator is a unit that regulates the charging of the battery by the alternator and maintaining a certain amperage while the engine runs. When the alternator is not working properly, this may result in the battery quickly losing charge and the car losing all power. You may also notice a whining sound as a result of the bearings inside the alternator begin to fail. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your charging system.

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My service charging system battery light is on after replacing my alternator with a brand new one. It is not charging my battery.
ANSWER : Hello, thank you for writing in. Several things may be going on. The installation of the new alternator needs to be verified, focusing on the electrical connections and the drive belt. Make sure the connections are clean, dry, and tight. Make sure the drive belt is routed properly and is tight on the alternator pulley (as it is what powers the alternator). If the installation was fine, you will want to make sure the alternator was not faulty from the factory. It is not common, but these issues have been known to happen. Most automotive parts stores can test the alternator off of the vehicle. If you would like more help with testing, contact our service department to schedule an appointment.

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Has new alternator, new battery when started , motor dies when battery is disconnected…my mechanics are stumped on this
ANSWER : Hello.

If replacing those particular components did not correct the issue then the next thing I would look at is the vehicle’s voltage regulator. It appears that this engine’s electrical system is equipped with an external voltage regulator that functions, or malfunctions, independently of the alternator. The voltage regulator regulates power from the vehicle’s alternator, and can cause issues with the electrical system when it malfunctions. I would test it to see if it is functioning properly. It is a silver box that should be mounted somewhere in the engine bay, usually on a wheel well. A technician from YourMechanic can come to your home or office to replace your car’s voltage regulator if necessary.


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Why won’t my 2004 Audi A6 Quattro charge brand new battery??
ANSWER : Hello. Most of the time the issue is in the wire coming from the battery to the alternator. This small wire has a tendency to fail and have high resistance. This needs to be checked first. If that is not the cause then you may have a computer issue. I would need to check that with a scan tool that will communicate with the vehicles main computer. If you are looking to have this done, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the vehicle is not charging]

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