To do this, you will need a car battery tester that has a multimeter with both volt and amp meter capabilities. Continue reading to learn some helpful car battery inspection tips.
Once you pop the hood, take a good look at the car battery. Check whether or not it seems to have any physical damage or natural wear. This includes rust, oxidation, corrosion, protrusions, scratches, indentations, bulges, and more. Corroded terminals can be cleaned with a toothbrush using a baking soda and water solution. But if a battery has physical damage beyond this, it is not safe to use and must be replaced right away.
Charge your car battery overnight, and then use your tester to measure its surface voltage. Be sure your engine is off before starting. First, connect the positive tip of the multimeter to the positive battery terminal, and then the negative to the negative. Next, read the surface voltage. It should be somewhere between 12.5 and 12.8 volts.
The alternator connects to the drive belt and rotates when the motor runs. This rotation produces voltage, which is a key component in charging your car battery. A poorly-functioning alternator will drain a car’s battery as you drive, so they must be inspected periodically to ensure its functioning properly. With the positives and negatives still connected from measuring the surface voltage, turn on the engine and allow the vehicle to run for a few minutes. The voltage should increase to anywhere from 13.6 and 14.3 volts.
Refer to your owners’ manual for your vehicle’s maximum amperage output. Once you have these values, switch your multimeter setting to amp meter. Turn on all the electronics in the vehicle and then measure the amperage output. If the values do not match your vehicle’s maximum amperage output, you could have an alternator problem.
Twist open the electrolyte cells of the car battery and check that there is a sufficient amount of electrolyte fluid inside. If not, top the cells off with clean distilled water.