Battery test after-market stereo question

I installed an after-market stereo in my car about a month ago. It works fine, powers down when I turn off the car, and disconnects from Bt connection to my phone which I think means that it is wired correctly to the power source. About a week and a half later I had problems with my battery dying. I started the car fine, drove about 10 minutes away and made a brief stop, and then the car wouldn't start. I got jumped and drove to Autozone. They tested the battery and it read out as being in good condition. Then it wouldn't start again. The AZ guy replaced my severely corroded/dirty batt
Experienced mechanics share their insights in answering this question :
First you had the battery tested at an AutoZone and I cannot know what they used to test the battery. Firestone my have used a load testing battery tester that can check to see if a battery can take a larger load. A resistance tester can see a good battery that a load tester will see a bad battery. If you have been having starting issues and had corrosion on the terminals the I would recommend replacing the battery.

How to Identify and Fix Common car Problems ?

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

Some cars will get up to five or six years out of their battery, while others will need a new one after only two years. In general, your car will usually need a new battery after three to four years. Replacing your car battery is another part of routine maintenance.
Connect the multimeter to the positive and negative battery terminals. If you don`t have a voltage of around 12.6 volts, you may have a bad battery. Now start the car, and look for a revised voltage over 10. If your voltage drops below 5 when the car is running, it is bad and should be replaced right away.
If you do not have the Owners` Manual, you can check the top or the body of the existing battery for all the required ratings. Never choose a battery that has Ah rating lower than your existing battery or as mentioned in the manual. It will give you starting trouble, especially when it comes to cold starts.
Life Expectancy

Generally, electric vehicle batteries last 10-20 years, but some factors may reduce their lifespan.

Ten-year sealed battery smoke alarms are powered by sealed lithium batteries that have a life span of ten years. These alarms provide 10 years of continuous protection with no need to replace the battery for the life of the alarm.
Check the voltage.

A good car battery should read 12.4-12.9 volts when the car is off. Anything lower doesn`t necessarily mean the battery is bad. Your car`s electrical system may have drained it, or there may be an issue with your alternator.

To check the voltage you`ll need a voltmeter, which can be purchased cheaply from most major automotive parts stores. Check the voltage of your battery using the voltmeter to help determine your next course of action. 12.6V volts or above – Your battery is healthy and fully charged.
A fully charged 12 volt battery should read at 12.6 volts on the multimeter. If the reading is lower than this, you`ll want to charge your battery with either a battery charger or by taking your car for a drive.
The ohmic test is also known as impedance test. A full cycle consists of charge/discharge/charge to read the capacity of the chemical battery. This provides the most accurate readings and calibrates the smart battery to correct tracking errors, but the service is time consuming and causes stress.
Things You Should Know

Standard car batteries last around 3–5 years. Electric vehicle batteries have a lifespan of around 12–15 years. Heat, repeated short drives, vibrations, and leaving lights on can all drain power from your battery and shorten its lifespan.

Ampere hours — sometimes abbreviated as Ah or amp hours — is the amount of energy charge in a battery that enables 1 ampere of current to flow for one hour. Another way of saying it is that 1 Ah is the rating indicating how much amperage a battery can provide for one hour.
Even though most car batteries are only 6 or 12 volts, a 12-volt battery can produce as much as 600 amps. Amperage can be thought of as the volume of electricity that`s generated, but the voltage can be thought of as the “pressure” of the electricity.
Ten-year sealed battery smoke alarms are powered by sealed lithium batteries that have a life span of ten years. These alarms provide 10 years of continuous protection with no need to replace the battery for the life of the device.
Battery Longevity

Typically, car batteries will last anywhere between three and five years. Because of this, most mechanics will recommend you replace your battery every four years or so just to be safe.

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.

08 camry hybrid. Hybrid battery seems to test ok, I removed the entire pack and load tested each cell, but i still get dash light
ANSWER : Hi there. Typically when a warning light is illuminated on the dash, it is due to an error code being created and stored in the ECU. In most cases, in order for the error light to go away, it needs to be manually reset and cleared from the ECU. To do this, it’s best to have a professional mechanic come to our location and complete a warning light inspection. This will allow them to determine if the problem is resolved or if additional repairs are needed.

When changing the car battery, do you "register" the battery to the car computer?
ANSWER : Hi there. Changing the battery has nothing to do with programming a battery. If the car was flat dead with a battery that lost all of the power because the dome light was on, then when jumped the vehicle will run fine. What may need programmed when the battery is replaced is the key fob. The key fob will lose programming to the computer as the vehicle computer is reset. However, if a 9 volt battery saver was put into a cigarette lighter and the car battery was removed, then the computer will not lose its memory and be just fine. If you need further assistance with your battery, then seek out a professional, such as one from Your Mechanic, to help you.

Went got a test at Autozone for alternator, she stated everything test normal but battery voltage is too low? What does that mean?
ANSWER : Hello. This could mean the alternator is not charging the battery high enough or the battery will not accept and hold a charge. You may need to replace the battery first, then recheck the alternator charging system for proper operation. If you need help, an expert from YourMechanic can come to your home or office to inspect why your battery does not hold a charge and replace the alternator if necessary.

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.

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.

Is my aftermarket stereo draining my battery?
ANSWER : A properly installed system should not drain your battery in 4 days. Obviously, the simplest way to rule it out would be to disconnect the stereo for a few days and see if that remedies your problem. If it does, you will need get your hands on an inductive ammeter that can read milliamps. You can clamp the probe around individual wires to see what the draw is on that particular line. There should not be more than 200 milliamps total draw when the car is shut off. But here’s where it gets more complicated. Your car’s body computer may be active for up to 20 minutes after you turn everything off, so the draw will be higher until the body computer "goes to sleep". That means it can be tricky to measure the shutoff current.Also, if your stereo is hooked into a line that is shared by the body computer, the computer may interpret it as activity, so it might not go to sleep properly. If all this sounds complicated, that’s because it is, but by contacting Your Mechanic you can have a qualified technician come to your home or office and check out your electrical drain and tell you what can be done about it.

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.