How to test your cars alternator

Video shows how to use a battery tester to check alternator output voltage. We also see how to use a multimeter to do the same test. Four vehicles are tested to illustrate that almost all vehicle alternators output the same range of voltage

[@TheLakotariver]

This is very clear. I now understand how to use my new Battery Analysis. Your video made it all the way down to Houston,Texas. Thanks from Texas :)

[@cayrick]

Couple of caveats on your video which is well done. It wasn't explained that you want to note that on the starter test you note the lowest point the needle touches as the minimum voltage and compare this to the value at the value in the yellow table at the bottom. If the needle falls below the table voltage value, the starter is a problem as it is drawing too many amps. You did not load test the battery; that is press the load switch and hold for 10 secs and take the voltage reading and compare it to the yellow table below to get cold cranking amps. Compare that to the rating on the battery. For the alternator test, in addition to the no load condition, you also need to turn on some loads in your car ac, rear defroster, headlights and see if the needle remains in the green band. When I did this with loads it went into the red zone and the alternator made a screaming noise; alt belt was tight. Would not have discovered the alternator problem without adding loads. Also when doing these tests you want the battery fully charged and eng. at normal operating temps.

[@jimjaeger8968]

It looked like you laid the metal load tester across both battery terminals.

[@ilmjcxj8064]

Excellent illustration. Keep up the good work.

[@csflmich2239]

Great video, explained well and done properly. Thanks!

[@robertclymer6948]

Thanks, very through and informative. Wish you would have performed the load test.

[@cars929]

ive got a battery gauge, and a sigarett outlet ( power outlet ) plug in - alternator and battery gauge - in the cab, highly recommended

[@modpup]

Great video

[@orfeous]

I did not see a load test on this video. This tool does not apply a load without pressing the button. This only worked like a multimeter when car is idle.

[@eddiekytia]

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[@zmby322]

but you didn't do the load test with the motor stopped to check the cca

[@nazukkoko7087]

Thanks

[@staresce]

How do you test the alternator on a car that is completely dead and will not start ( the battery tested okay) ?

[@backyardmech]

If you can't get the car started ; you can't test the alternator using the method i show here Lisa. If you can start the car by jump starting it , you can test the alternator as shown in the video

[@404notfound.....]

If your battery tested OK its not your alternator but your starter, Your alternator takes over and starts charging after the vehicle starts. Find somebody with a test light and verify that you have power running to the starter if you do then most likely its the starter itself. hope this helped.

[@31acruz]

Redundant

[@applepoop10]

Didn't actually test for CCA of the car battery.....