battery won’t stay charged.

I put a new alternator and a new battery. The car starts but slowly dies and the battery hand goes up and down when I use the turn signal

My car has 286000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hello. This is a common problem when there is a bad ground connection or a faulty voltage regulator. The bad ground connection will cause the system to fail to complete the circuit which will not allow a full charge. The voltage regulator moderates the charging of the battery by the alternator. When this is not working properly, this will cause the alternator to either overcharge or undercharge the battery. I would recommend having an expert from YourMechanic come to your home to diagnose why your battery won’t hold a charge and repair the voltage regulator if necessary.

How to Identify and Fix Common car Problems ?

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

Charging problems can be caused by electrical faults in the alternator or voltage regulator, poor wiring connections at the battery or alternator, or a slipping or broken drive belt. Since most late-model import alternators are internally regulated, a failure of the regulator means the alternator must also be replaced.
If the alternator`s fuse or fusible link is blown, the alternator will not be able to charge the battery. The battery then doesn`t store enough power for starting the car or keeping it running.
If your Ford Expedition battery warning light comes on while driving, be sure to turn off your accessories, so the battery doesn`t drain further. The warning light usually means that the alternator isn`t working accurately meaning you`re operating solely on battery power.
It is possible that the problems that you have been experiencing with the bad alternators have damaged the battery causing it to be weak. This would make the Battery Light come on. It is also possible that there is a problem with the fusible link or the alternator fuse for the charging system.
Poor ground connections are an often-overlooked cause of low charging output and alternator failure.
Your car`s alternator may fail for various reasons: Age and use-related wear is often the reason behind a dying alternator. Engine oil or power steering fluid leaking onto the car alternator can lead to its failure. Prolonged idling while using multiple electrical accessories can prematurely wear the 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.
One significant reason why a car battery won`t hold a charge is age. Obvious signs that your battery is too old and worn out include corrosion and cracking. If it`s at least four years old, then it should probably be replaced. For younger batteries, a car that isn`t started for days or weeks can also lose its charge.
If your car`s alternator belt isn`t working properly, your car battery won`t get the charge it needs for your vehicle`s electrical parts. With that, your car battery light will frequently be on to indicate such an issue.
An illuminated battery indicator can be caused by a number of issues, including: A loose or corroded battery cable. A problem with the alternator or voltage regulator. Damaged cells or plates inside the battery.
The red battery light could indicate a problem with the alternator, battery or other parts of the electrical and charging system in the car. It could be a minor problem such as a malfunction rectifier unit, blown fuse or cabling short circuit.
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.

While a car alternator usually lasts the car`s lifetime, it can deteriorate and malfunction under certain circumstances. Factors such as normal wear and tear, damaged parts, exposure to water or heat, and overuse can cause your alternator to stop working.
If the voltage drop exceeds specification, check for corrosion, frayed strands of wire, loose connections or a battery cable gauge that is too small. Ensure the vehicle`s batteries have been tested and that the terminals have been cleaned and tightened. 1) Ensure the battery is charged to 12.4 volts minimum.
A bad alternator won`t sufficiently charge the battery while the engine is running, causing the charge to deplete faster than usual. One way to test whether the issue is battery- or alternator-related is to jumpstart the car. If you jumpstart your car and it stays running, your battery may need replacing soon.

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 : 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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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.

Read Full Q/A … : battery won’t stay charged.

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

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Just replaced battery now car won’t start on it’s own has to be jumped I charged the battery all the way now all it does is click
ANSWER : It sounds like you may have a faulty battery or possibly a bad connection somewhere. If the lights dim when starting the car, this suggests the system is straining to gather enough power to turn the motor over. I would recommend having a professional from YourMechanic come to your location to diagnose and test your battery to be sure it is properly charged and capable of holding a charge.

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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] https://www.yourmechanic.com/services/battery-will-not-hold-a-charge-inspection

Read Full Q/A … : battery won’t stay charged.

the battery won’t stay charged.
ANSWER : I would first verify that the vehicle has a drain above 200 milliamps by disconnecting the battery’s negative cable and putting an amp tester between the post and clamp.

The test should be done correctly by having the tester attached and touching the clamp to the post and when removing and getting the amp reading. If the test is done properly and everything is off, then there should not be more than the 200 milliamp draw.

If it is more than that, then I would start removing one fuse at a time in the engine fuse box until I isolate the draw to a certain circuit. Then I would trace the circuit to see what is drawing the battery. For example, you can try opening your trunk an checking the trunk light to see if it is hot as soon as you open the trunk. This indicates it was on when the trunk was closed.

If you would like help finding the parasitic draw, a certified technician from YourMechanic can come to your home or office to diagnose your car’s battery issue and make any needed repairs.

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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 car won’t stat,dead battery expected the battery’s fully charged?
ANSWER : Hey, thanks for writing in about your 2003 Cadillac CTS. It certainly sounds like your battery is the issue. It is possible for it to take a charge and have voltage but not have the capacity to start your vehicle. If you want to have this taken care of, a certified technician from YourMechanic can come to your home or office to perform a load test on the battery and replace the battery if necessary.

Read Full Q/A … : battery won’t stay charged.