Yes, car batteries need replaced just as flashlight batteries and such. A new 12-volt car battery, fully charged, should be putting out about 13.5 Volts. So to charge a battery that is nominally 13.5 volts, you need 14 to 14.5 volts to make things happen. If the car is less than 14.0 volts when running, you may have an alternator problem.
With the car off, your battery should be at 13.0 to 13.5 volts, once it is charged. Below 12.0 volts, your battery is likely shot. You can use a voltmeter to test your battery, many automotive places have one and will test your battery for free. If your battery is at 11.5 Volts it may not start the car. ;Car batteries do not have a lot of depth of charge which means this depth becomes shallower over time. As a car battery ages, it may hold little more than a surface charge. People with subwoofers often install a separate battery to power them. The standard car battery can easily be drained flat by large aftermarket subwoofer amplifiers and other audio, video, and navigation accessories.
Posted in 
Tags: