Testing your car battery will help you to identify if it needs to be replaced in the near future. To safely test the car battery, you'll need work gloves, safety glasses, a voltmeter, and small wire brush. Turn the vehicle off, open the hood and give the battery terminals a good inspection. If there's any corrosion, use the wire brush to create a good contact point.
Take the red cable from the voltmeter and attach to your battery positive terminal. Take the black cable from the voltmeter and attach to your battery negative terminal.