Battery not staying charged

Battery keeps going dead

My car has 297000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi, thanks for writing in. This is likely a charging system problem or potentially a bad grounding connection. Check to be sure your battery cables are clean and free of corrosion and that the black (ground) cable is properly connected to the chassis of the vehicle which ensures a proper ground. If the connections check out fine, then you likely have a charging problem which is usually related to a faulty alternator or voltage regulator. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make or suggest any repairs as needed.

How to Identify and Fix Common car Problems ?

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

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.
Defective charging system – A car battery drains quickly if something called the alternator on your charging system fails to push out enough voltage, ideally between 13.5 – 14.5 volts. In this case, the battery will continue to drain even while the car is running.
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.
The most serious reason why your battery runs down while charging could be that the sub-board is bad. The charging port is connected to the sub-board, so charging issues like overcharging, overheating, voltage fluctuation can cause damage to the sub-board.
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.
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.
Using a test switch and digital ammeter is the simplest, most accurate way to measure parasitic drain directly. A test switch goes between the negative battery terminal and negative battery cable.
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.
The ignition relay is essentially an electrical device that works as a switch for the power to the ignition system. Its job is to make sure electricity flows from the battery to the different components that need power. A bad relay will drain your battery and make it difficult to start the ignition.
Symptoms of a burnt out diode:

The engine will begin to run rough, lack power and eventually stall and not start again. The battery warning light will turn on, warning you that there is a problem with your alternator charging system. The headlights will become dim due to reduced battery voltage.

Issues such as faulty wiring, bad fuses or interior lights that fail to shut off will continue to drain your battery while it`s idle.
The battery can be fully charged but still not be able to start the vehicle if it is failing or has a dead cell. Other likely issues are the fuel pump, ignition switch, battery cables, starter, or a clogged fuel filter.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Battery light stays on and overnight battery drain. 2006 Land Rover LR3
ANSWER : Hi there – yes, something is going on here that’s draining your battery. Perhaps the pressure of the engine wash dislodged wiring which has shorted, or there was a chemical reaction to the cleaning solution that caused electrical damage in the alternator or voltage regulator. These componnents can be checked off of the vehicle. Vehicle wiring 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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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] https://www.yourmechanic.com/services/battery-light-is-on-inspection

Read Full Q/A … : Battery not staying charged

Battery light stays on and overnight battery drain. 2006 Land Rover LR3
ANSWER : Hello – 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 identify, replace or repair the failing component.

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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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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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Oil pressure and battery light stay on when ignition is off.
ANSWER : Hello. If this is occurring, then there is a short in the electrical someplace. Most of the time, the issue is in the ignition switch. The switch fails internally and causes some circuits to stay on which will drain the battery. It can also be a short in the harness or in the fuse box but the ignition switch is the most common on this car.

If you want to have this electrical issue checked out, consider having a certified mechanic, such as one from YourMechanic, come to your home or office to inspect the electrical system and suggest any necessary repairs.

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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.

Regards,
Eduardo

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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.

Read Full Q/A … : Battery not staying charged