Dead battery

My battery is dead.
Experienced mechanics share their insights in answering this question :
Once the battery is replaced, have a trained technician, like one from YourMechanic perform a charging system test to make sure the alternator is charging the battery. If the alternator is not charging the battery the battery will run down again. These tests will let you know if you need to replace the alternator or the battery.

How to Identify and Fix Common car Problems ?

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Sometimes a vehicle starts, but instead of idling, the engine immediately dies. In this case, the battery`s charge may be just enough to turn over the engine. However, the battery then fails, causing disruptions in the signals sent to the engine control module (ECM), and the engine then dies.
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.
If the battery is completely dead, it won`t have enough power to turn over the engine, even with a jump start. In this case, you`ll need to replace the battery to get your car running again. Another reason why a car battery won`t jump is because there is a problem with the charging system.
A fully charged battery should register at 12.7 volts or more. If the voltage falls below this number, the battery should be recharged. A battery is only charged by one quarter at just 12 volts. Once it drops to 11.9 volts, your battery is considered dead.
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!
Yes, a dead battery will cause your vehicle to function progressively worse until it finally grinds to a halt on the side of the road.
Typically, your car can sit about four weeks to two months without driving before the battery dies.
If a battery is completely dead but has been revived by a jump start, there are ways to fully recharge your battery. The first is, as mentioned, by driving around. If that does not seem to work, however, car battery chargers can regenerate all of the charge into a battery.
A normal-sized car battery can be fully charged in 2 to 4 hours with a 20 Amp charger, and with a 4Amp charger, it takes around 12 to 24 hours. You can also jumpstart your car`s battery using another vehicle. If you can get it started, idling is also an option for charging the battery.
If the measured reading is less than 12.2 volts, the battery`s resting voltage is weak, which means it most likely needs to be charged or replaced.
12.0 volts or below – At 12.0 volts your battery is considered to be fully discharged or `flat` and should be recharged as soon as possible. The lifespan of your battery will be severely affected if it remains within this voltage range for extended periods of time.
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.”
Parasitic Drain

A small amount of parasitic drain is normal and expected, since things like your clock and audio system need some power to avoid being reset every time you turn off the car. However, excessive parasitic drain can be a problem, leaving your battery empty by morning.

How Long Can a Car Battery Sit Unused? How long does a sitting car battery last? A car battery can last about four weeks to two months before it dies. Your car battery can only last so long before it fails when you`re not driving because of key-off drain.
The answer can vary depending on your car battery age, type of vehicle, and the weather. Typically, your car can sit about four weeks to two months without driving before the battery dies.
Can a completely dead battery be recharged? If the battery is your only problem and the car is in otherwise good working order, it is quite possible to completely recharge a completely dead battery. Using the charger or a jump start or push start and then letting the engine idle with electrical items switched off.
Can a completely dead battery be recharged? If the battery is your only problem and the car is in otherwise good working order, it is quite possible to completely recharge a completely dead battery. Using the charger or a jump start or push start and then letting the engine idle with electrical items switched off.
Can a completely dead battery be recharged? If the battery is your only problem and the car is in otherwise good working order, it is quite possible to completely recharge a completely dead battery. Using the charger or a jump start or push start and then letting the engine idle with electrical items switched off.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Battery went dead. Replaced battery. Engine and battery lights are on.
ANSWER : Hi There,
As you know, your problem may be related to a faulty alternator resulting from it not properly charging the battery. This may also be related to a faulty voltage regulator. The voltage regulator regulates the rate at which the alternator charges the battery. When this is not working properly, this may allow the alternator to over or under charge the battery, in either case resulting in the battery failing prematurely. I would recommend having an expert from YourMechanic come to your location to diagnose your charging system.

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2011 Nissan will not crank and the battery goes dead after one year.
ANSWER : Hi there. The battery is the remote key fob will only last about 8 years. Since it is now 2017, the battery is now 8 years old and could have lost its charge. The chip in the key tells the computer (ECM) to start the car. If the vehicle continues to eat away the battery in the key fob, then either a button is stuck on the key fob or there is a parasitic load (something that is on that is to be off) in the car causing the key fob to drain the power as the engine is running. If you need further assistance with your car not starting, then seek out a professional, such as one from Your Mechanic, to help you.

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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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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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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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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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Hi Roberts. How would you rate a Subaru Outback battery compared with consumer reports best rated battery like diehard, and others
ANSWER : The very first thing to do is have the battery load tested. If the battery passes a load test be sure it is NOT a marginal pass in which case you should simply install a new battery to reduce diagnostic headaches. As far as buying a new battery, there are actually relatively few battery manufacturers and so a lot of the output is identical but just carries a different brand name. You would be wise to consult "Consumer Reports", as they have already done all of the required battery research for you and so you can safely and reliably purchase whatever they deem to be a top rated battery. If and once you replace the battery, be sure to measure the output of the charging system to confirm that the alternator is properly re-charging the battery. Please let us know if you have further concerns or questions as we are always here to help you.

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I have Chrysler 300c. Battery light came on, changed battery and alternator but power still getting drained and battery light still comes on.
ANSWER : Hi, thanks for writing in. This may be a sign of a failing starter relay. The starter relay is a small unit near the starter that directs power to the starter from the battery. When this fails, it may cause a clicking sound and will not allow the starter to engage the flywheel when you turn the key. I would suggest having a professional from YourMechanic come to your home to diagnose your starting issue to determine the solution to get you back on the road.

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