Are you having trouble starting your car? A bad battery is one of the things that can cause a vehicle not to start, especially after a cold night or if your car has been parked for a long time.
If you’re wondering whether your battery is the problem, it’s relatively easy to test it. All you need is a voltmeter or a multimeter on the voltmeter setting.
Here are some tests you can do to check your battery’s voltage and your vehicle’s charging system.
How to Test Your Battery’s Voltage
You can do a simple test to see if your battery is holding a charge. With the ignition off, connect the positive (red) cable on the voltmeter to the positive terminal on your battery, which will be marked with a plus sign (+). Connect the negative (black) cable on the voltmeter to the negative terminal, which will be marked with a minus sign (-).
The voltmeter should read 12.6 volts if your battery is holding a charge. Even a slight drop indicates that your battery isn’t fully charged, so even a reading of about 12.2 volts may indicate a problem with your battery.
Note that the cold will cause a lower reading. For instance, at 30 degrees, a good, fully charged battery will still only read about 12.5 volts, so don’t worry about a low reading if the battery is very cold when you test it.
Even if your battery reads as fully charged, though, that doesn’t mean it’s good. There’s one more test you need to perform to check your battery’s performance under load.
How to Test Your Battery Under Load
Starting a car draws a lot of current, and often batteries fail because they’re no longer able to hold their charge under load, as it’s called. To test your battery under load, you’ll need to test it while cranking the engine.
To do this, you’ll need to disable the ignition so that the car won’t actually start. Then, with the voltmeter cables hooked up as described in the above section, have an assistant crank the engine for 10 or 15 seconds while keeping an eye on the voltmeter. The reading should never drop below 9.6 volts. If it does, the battery is bad and will need to be replaced.
Have Your Battery Tested for Free
Testing your battery’s voltage is fairly easy, but in order to fully test your battery’s operation, you’ll need some minor automotive knowledge. If you don’t feel comfortable with this, many mechanics and parts stores offer free battery testing. They can usually test the battery whether it’s in or out of the car, although in some cases, if the battery’s voltage is low, the battery may need to be charged before running the test.
If you would like to have your battery tested for free, bring your car by Nissan 24 in Brockton, MA, and ask for our service department. We’ll test your battery for you and tell you quickly and accurately whether you need a new one or run further diagnostics to find out what the problem is.