Your car's battery is the brain of the electrical system. What I mean is...Without it nothing works. Just like a battery in any electronic device, your car's battery will need to be replaced every 3 to 5 years on average. Some car batteries require periodic maintenance and need to be serviced on a regular basis to obtain optimum performance, although others are referred to as [maintenance-free], meaning that they don't need any service.
There are a number of automotive problems that can occur with symptoms that seem like a dead battery but, with the suitable tools and knowledge, these can easily be diagnosed before you go out and buy a new battery unnecessarily. For your connivance there are Battery Tenders available that will keep your battery in top condition.
Things You'll Need...For Diagnosing a Car Battery Problem...
>>>Battery testing meter.
>>>Battery load tester.
>>>Open end Wrench(s).
>>>Battery terminal cleaning solution.
>>>Battery terminal cleaner [some 100 grit sandpaper works to].
Using a Digital Multimeter to test the batteries voltage level. A battery in ideal working condition should read 12.66 volts DC between the positive [+] [RED] and negative [-] [BLACK] terminals. This number could be a little higher or lower depending upon its size and producer, but should not be less than 12 volts, and no more than 13 volts. If a battery has fully charged and reads a voltage less than 12V at rest, you may need to check the battery's water level and top it up necessary. If the water level in the battery is OK, it may need to be replaced.
NOTE...If you're not sure how to check the water level, have a qualified person check it for you.
Now inspect the battery terminals for signs of corrosion and lose connections. It's very common for corrosion to form on the battery terminals. In numerous cases it's quite visible, but it's even possible for corrosion to be obscured between the terminal and the connector. This might lead to inadequate charging, likewise a loss of power to the car. Remove both terminals and clean them with a battery terminal cleaning solution and a wire brush or [100 grit sandpaper]. Reconnect the battery terminals and tighten them.
The next step is to check that ground cable is properly grounded. Follow the negative [-] [BLACK] wire from the battery terminal to where it grounds to the frame of the car. Use the multi measure to test the resistance between both ends of the wire. A good ground cable will show 0 ohms, or very close to it. Any reading more than 1 ohm indicates a bad ground connection. Repeat this again between the negative terminal and the vehicle's body ground.
Now we're going to perform a load test. Place the Battery Load Tester between the positive [+] [RED] and negative [-] [BLACK] terminals. When this load test is being performed, this meter will show the battery's functioning under a actual load. If the battery has been adequately charged and fails the load test, replacement of the battery is necessary.
Testing the alternator to determine if its sending adequate power to the battery. Using the multimeter to test the battery's voltage [as per above] with the vehicle turned off. Now start the car and test the voltage reading again. While the car is running, the voltage should read close to 14.4 VDC. If the voltage is reading the same when the car is running as it is when it's turned off, or if the voltage drops while the car is running, the alternator might not be working correctly and may need to be replaced. If the alternator isn't properly keeping the battery charged, the symptoms will be very similar to those that happen with a dying battery.
Some Tips & Warnings To Be Aware Of!
>>> Dirty or poorly connected battery terminals are the most frequent reason for battery related car problems. Always clean [try some baking soda & hot water mixture]and tighten the battery terminals before going out and buying a new battery...Always dispose of dead batteries correctly.
>>> Make sure you wash your hands after handling a battery. [Or better yet wear gloves]. Automobile batteries may contain sulfuric acid, and the terminals are typically made of lead. Don't smoke while servicing a battery. Hydrogen gas could be released from certain types of car batteries, and an blowup may happen.
>>> It's always a good idea to keep your car and it's battery properly maintained. There are Battery Tenders available to ensure your battery is in top condition and will be ready to start your car when you need it.