My car battery keeps dying after a few days of be fully charged my alternator is good what can be the problem?
My car battery keeps dying on me after I fully charge it few days before. My alternator is good, is there anything else that could be draining my battery?
My car has 94000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hi there. On most cars, trucks and SUV’s sold in the US, the battery is used to engage the starter and power accessory components while the engine is not currently running. Due to this fact, if any accessory is left on, it might continue to draw power from the battery, causing it to loose power. This is known as a parasitic drain, and happens more often than it should. Due to the fact that there are more than 40 unique accessories that draw power from the battery while the engine is not running, it’s probably a good idea to have a professional mobile mechanic to come to your location and complete a battery will not hold a charge inspection. This will allow them to pinpoint the source of the battery drain and make repairs to resolve this issue.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
Failing Battery
If your battery has been run dead too many times, has too much internal sediment buildup or is simply too old, it may be losing its ability to hold a charge. This means as soon as you turn off the engine, the battery starts discharging on its own even if the alternator works fine.
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.
Even while your car is off, your battery provides power to things like the clock, the radio, and the alarm system. These things shouldn`t have a major impact on your battery. What may drain a car battery when it`s off are things such as interior lights, door lights, or even bad relays.
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.
Contrary to its purpose, an alternator can drain a battery. It`s rare, but it`s possible. A draw on the battery only occurs if there`s a problem with either a component in the alternator itself or connections to it.
Some of the most common reasons for a car battery to die repeatedly include loose or corroded battery connections, persistent electrical drains, charging problems, constantly demanding more power than the alternator can provide, and even extreme weather.
“Electrical devices or lights left running, a defective charging system or alternator, and extreme weather are some common reasons but maybe it`s just time to get a new battery.”
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.
There are some reasons a car battery may not hold a charge. The most common cause is that the battery is old and needs to be replaced. Another possibility is that the battery has been damaged by heat or cold.
Here are some of the most common ones: There are too many push notifications and alerts draining the battery. There are too many apps running location services. There are too many apps running in the background.
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.
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.
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.
If your alternator fails when you`re far from home, you can typically drive up to 200 miles on battery power alone. That`s assuming your battery is in good shape and fully charged. Of course, it`s best to get the alternator repaired or replaced as soon as you can.
“If the [battery`s] voltage is low, replace with a new battery or charge the battery to the recommended 14.2 to 14.7 volts,” he says. “Then try to run the vehicle and see if the voltage after is outside of that range. If it is, that`s a sign of a bad alternator.”
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 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.
There are some reasons a car battery may not hold a charge. The most common cause is that the battery is old and needs to be replaced. Another possibility is that the battery has been damaged by heat or cold. If you think your car battery is not holding a charge, it is vital to take action.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
My car battery keeps dying after a few days of be fully charged my alternator is good what can be the problem?
ANSWER : Hi there. On most cars, trucks and SUV’s sold in the US, the battery is used to engage the starter and power accessory components while the engine is not currently running. Due to this fact, if any accessory is left on, it might continue to draw power from the battery, causing it to loose power. This is known as a parasitic drain, and happens more often than it should. Due to the fact that there are more than 40 unique accessories that draw power from the battery while the engine is not running, it’s probably a good idea to have a professional mobile mechanic to come to your location and complete a battery will not hold a charge inspection. This will allow them to pinpoint the source of the battery drain and make repairs to resolve this issue.
I have replaced the battery and alternator and the charging system light keeps popping on and then the car dies after a day or two
ANSWER : The problems you are describing do seem to lead me back to the charging system circuit. If the vehicle shuts down because of a dead battery, the problem has to be in the charging system as it is designed to maintain the battery charge while the vehicle is in use. Loose battery cables or corrosion like the technician said can cause problems as well. Consider hiring the aid of one of our mobile experts for a personal diagnosis of your charging system.
My battery light is on.
ANSWER : The problem is not the battery, but the charging system is not keeping the battery recharged. The alternator is the most common cause of this, though failing battery cables can also be a cause. I would recommend having the battery cables and alternator tested and checked by a mechanic, like one from YourMechanic, who will come to you and diagnose the problem for you. Do not try and drive it or it will leave you stranded from the battery going dead again. The cables to the battery from the alternator may be bad or the alternator is not charging. Only the testing and diagnosis will reveal the problem.
Replaced alternator on car 2 times each time shows it’s charging 14v let car run for a little bit then test drive and car voltage
ANSWER : There are reports that the replacement alternators will not communicate with the engine computer and will not charge correctly. I recommend using only the manufacturer approved replacement part. It can be new or remanufactured but approved for use in the vehicle. Some lower cost alternators on the aftermarket will have charging problems since they will not communicate with the ECM on the vehicle and will stop charging.
Battery good, alternator good, brand new alternator cable, still not charging.
ANSWER : Hi There,
The first diagnosis of the bad voltage regulator is likely the cause of your charging system not properly charging the battery. 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. 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. In some cases when a battery is too weak or damaged, it may no longer hold a charge for any length of time, in which case the alternator may be doing its job, but the battery is just simply too weak to hold a charge. In either case, I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle’s charging system.
The first diagnosis of the bad voltage regulator is likely the cause of your charging system not properly charging the battery. 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. 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. In some cases when a battery is too weak or damaged, it may no longer hold a charge for any length of time, in which case the alternator may be doing its job, but the battery is just simply too weak to hold a charge. In either case, I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle’s charging system.
is the ecm the problem if battery light is on and the alternator isn’t bad
ANSWER : This is likely a sign of a failing voltage regulator. This is a unit that regulates the charging of the battery by the alternator. In your case, it sounds like the voltage output from the alternator may be much too high resulting in overcharging the battery and burning up wires in the process. I would recommend having an expert from YourMechanic come to your location to diagnose and properly test your vehicle’s charging system.
Battery dying and both alternator and battery passed for good when inspected
ANSWER : If the battery passes a load test and charging system output has been measured and is within specifications, the only reason a battery will discharge is if the car sits for a long period of time (batteries will self-discharge even if not used) or if there are parasitic (excess) loads on any of the car’s electrical circuits. If there is excess current flow that is slowly draining the battery, a Mechanic would use an ammeter to test all of the various circuits until the faulty circuit is found. Then that circuit is traced to find the fault and repair it. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an electrical diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
Car dropping battery charge on start up, then dying after driving for a bit
ANSWER : Hi there:
Once your engines starts, the job of the battery is complete and falls on the alternator to power all vehicle accessories and electrical systems. The issue may be with the alternator or some of the electrical relays that distribute power to these components; as opposed to the battery itself. To be certain, you might want to contact a mobile mechanic from YourMechanic.com to complete a battery won’t hold a charge inspection; so they can determine precisely what’s causing this issue with your Audi.
