How to Check a Car Battery for Corrosion

Video Transcript

"Hi, I'm Aaron Gregory on behalf of Expert Village. We're going to talk about what happens when your car battery dies, how to select a new battery, and how to see what the problem is. Okay, here is the car battery in this particular car. Some cars will have the battery in different locations. A Volkswagon Beetle will have a car battery under the seat in the back of the car. Most cars now have them under the hood easiest to service, out of the passenger compartment. We're going to check for dirty terminals, rust, and maybe loose connections. And, we're going to see if we can get this battery to work. First thing I'm looking for is white corrosion in the connecting areas where the cable terminal next to the battery itself. So, some batteries have a side post which means that the connecting contact point is on the side of the battery. The side post terminal will be a round, flat piece of copper like a washer with a cable extending from it and bolt through into the battery on the side or the top. Most newer cars have a bolt in terminal. Most older cars have a clamp style. The clamp style is more prone to rust and corrosion. But, just by wiggling this, I found the loose terminal. And, that's going to cause a problem. And, if a terminal is loose, it will also encourage corrosion to grow. And, if corrosion starts, it starts corroding the battery tray under the car, and it will eat down into the wire. Sometimes you can find corrosion inside one of your battery cables by using a razor and slicing open the rubber shielding on the cable. And, you'll recognize a greenish color to the copper wire strands. And, you'll see a white powdery stuff. And, if you flex the cable, we can bend the cable once we take the terminal off. And, if it feels crunchy inside, that's a sign that the cable needs to be replaced or maybe just cut off a few inches to where there's clean copper inside, and then, clamp a new terminal end on it. The corrosion doesn't look too bad on the battery terminals or in the wire strands. If you notice any corrosion on the battery, such as this white powdery stuff or rusty looking stuff, you can clean it off and neutralize it, neutralize the acid with a mixture of water and baking soda. You simply pour it over the battery, and it will foam up and then you can rinse it off with clean water. A little water around the battery will usually drain off onto the ground without causing any problem to under hood components. But, make sure you don't pour it into the fuse box. So, first let's clean these terminals and reconnect the battery nice and tight and then see if we get any power out of the car, see if the headlights come on, see if the starter will turn the engine. I'm going to get a wire brush and clean these terminals. "