How to Test a Car Battery with a Multimeter

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Use a multimeter to test a car battery fuse. Learn how to check if a car battery is working in this free video.

Part of the Video Series: How to Change a Car Battery
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Video Transcript

Hi, I'm Aaron Gregory on behalf of Expert Village. And, we're going to talk about what happens when your car battery dies. To test the battery and the fuses, I'm going to need to use a multimeter. This is not a digital. This is an analog multimeter. You can tell by the needle and the dial which means it's analog. Digital would have a digital read out. It comes with two wire leads, black and red. Red is positive. Black is negative. This little meter can do a lot of different things, but you need to know how to use it. Now, there's an ohm's scale which is ohm times one thousand. And, ohms are a scale of resistance or continuity. For testing fuses, we want to test for continuity, which means continuous electron flow through the fuse like a loop. So, if we turn it to the ohms scale and we touch the wire leads together, the needle goes to the top of the scale. That let's me know that there is continuity or a continuous loop of electricity flowing through the leads. We're going to do this same thing incorporating a fuse into our circuit. Now, if the fuse is good, it will show continuity and the needle will go to the top of the scale. If the fuse is burned, nothing will happen because the electricity is not getting through the fuse which is protecting your car. Let's move on to the main battery fuse and test it. To test the fuse, we're going to take our meter and we're going to put it on either side of the fuse legs which are screwed down into the fuse box. But, if there's a battery connected to the car, there should be twelve hot volts at the fuse which will burn our meter and give us a funny reading. So, we need to disconnect the battery terminal one more time. With the meter on the resistance scale and the meter where you can view the window, take your test leads and attach them to the opposite legs of the fuse. As the needle swings, we can see that there is continuity through the fuse and the fuse is not the problem. With our multimeter, we can also test the battery for voltage. Since we've done all these other checks, and the battery's still not performing, we're going to see if this battery has any voltage in it. With the multimeter set on the fifty volt scale, which is a maximum of fifty volts ranging everything from zero to fifty, twelve volts falls into that range. So, I've got it set on the fifty volt scale for direct current. Batteries supply a direct current voltage. Connect your red meter lead to the positive battery terminal, and the black to the negative battery terminal. Looking for the needle to move, I see about four volts which tells me that this battery is very dead. Moving the selector down to a maximum of ten volts, I can get a more accurate reading of what's in the battery. It appears to have about three volts in it. Which is not nearly enough to start our car. We're going to need a new battery.

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