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How to Test an Alternator

Figures Chris fix here to initiate a test your alternator make sure it’s working right some symptoms you might have with the bad better your bed alternator is that your battery late might be on the dash the engines cranking Soulier won’t crank it all the battery seems weak interior lights or headlight seem weak rumbling or squeaking noises come from the alternator which indicates that there could be a bad bearing these are symptoms of a bed alternator or battery to see it a test the battery check out my other video the link is in description below this video specifically for the alternator.

alternatorI’m gonna show youeverything that you need to know about how to test the alternator so when you’re doing this test UNICEF your multimeter to de CV which is DC volts and you want to set the something about 15 so 20 in this case. Here’s the negative terminal on the positive terminal on the battery going make sure these terminals are clean so that you get a reading when you do this test zone that I put my back to my negative and read to the positive here. And you could see you 112 0.6 volts or something around that it could be a little bit lower a little bit higher that’s not a big deal but 12.6 is the magic number to shoot for now to see if the alternators working properly we have this attached we’re gonna start the car and ideally what should happen is that you go between 14.2 and 14.7 volts and that means your alternator is running correctly and charging the battery it correctly if you’re getting over 14.7 votes that means that your alternator is over charging the battery and that could cause damage to the battery.

So you don’t want that an under 14.2 depending on how much under let’s just say 13.2 that means you’re theaters and strongly charging the battery it’ll still charging costs still above this 12.6 volts but not enough to charge you when you’re running Cesaris such as your headlights and radio let’s start the car so I could show you what I’m talking about. So you can say it’s running about 14.2 and that’s exactly where we want to be there’s a voltage regulator in the alternator that regulates the voltage at this should be a and 14 points at a 14.7 is exactly where we want to be and that’s spot on again if this is bad it’ll be there below the 14.214 0.7 ranger above. Now we’re gonna put a load on the battery alternator so we’re gonna turn the lights on organ turn the radio on I have off road lights on them to turn those on and all that stuff together is gonna put a load on this and what we should say is this shouldn’t drop too much will make sure the vote there’s nothing go below 13 votes.

Now right now I have a lot of things on I have 41 0 watts off road lights on. And my headlights. Fog lights on at the radio on and I have a fan on andwith all that stuff the voltage is still almost 14 which is great we don’t want this to drop below 12.7 with all that stuff gone bad you could say my mild Nader’s running very now gonna shut up everything I turned on you’ll see the suspect Becca. So now when we started I had 12.6 votes when I shut the car off it should be higher than 12.6 and that means that the old leaders charging the battery. So we just shut it off and we could see that it it’s 12.9 votes this is the service charge eventually this will drop back down to 12.6. So while doing this test something doesn’t check out your voltage doesn’t go up in the cars running or when you turn all the accessories on the voltage drops below 13 volts if that’s the case then we’re gonna check out a couple things first off.

You wanna check out the connections here take the leaves off the terminals and send it and get a really good connection because sometimes the connection isn’t good and that’ll cause the out there have a hard time charging the battery. Another spot to look at is the back of the alternator make sure all the wires are plugged in and secured. Minor plugged in obviously but make sure yours are and filed this and make sure that this. Goes all the way to the battery and isn’t disconnected at all check for any corrosion any damage to the wires any frayed wires any kink wires all that stuff could cause a problem also your alternator might have an external voltage regulator check the wires to the external voltage regulator make sure that it’s going there make sure to Clinton and make sure the external voltage regulators working.

Finally as the cars running make sure that the alternators spinning make sure that the bill is tight your mix your belt is tight on Elton here because that’s how you get your power no less testing and show you guys is the voltage drop tests for the negative and positive sides of the battery first will test the voltage drop on the negative side the battery to do this test go start the car turn on a bunch of accessories you want your headlights on you want your lower fan on your radio on and then I’ll come back out here and I’ll show youwe’re gonna connect the black lead to the negative side the battery.