When you want to make sure that the battery in your car is still holding its charge, you can use a voltmeter to test it. A pair of rubber gloves and goggles will protect you from any acid.
To hook a voltmeter to your battery, attach the positive terminal first and then the negative. The key should be removed from the ignition, and make sure your lights are off. A reading above 12.4 indicates a healthy battery, and one below 12.2 shows that it's holding 50% or less of its charge. When you're finished, remove the negative terminal first.
Many batteries stop holding their charge after five years and can leave you stranded in an unfortunate situation. If it's time to replace yours, bring your vehicle to Ourisman Ford & Lincoln in Alexandria, VA today and get a new one installed professionally.