How To Test An Alternator | How To Check An Alternator

Today, I briefly demonstrate how to check an alternator to see if it's charging properly or not without having to bring your vehicle to the shop or remove any parts.

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[SeanLuc_Photo]

Thank you for explaining and recording how to perform this check.

[randypickerign]

Very good video thank you for explaining everything

[lesbowhite]

Thanks well explained video for an old fella to follow

[bigblack]

Very nice… I watched 2 other videos that left me a little confused… Your video was clearly the best!

[Vcoldduck]

great Job. No one else included the direct to the alt. test.

[Apostasy_Plague]

parkway drive, nice. big nostalgia blast from 2007-2013.

[larrycroft]

Tony thank you for this video. I have a battery icon light coming on my 11 Kia Sportage (no gauge) and i suspect the original alternator is giving up. Thanks to you i will be able to verify that and replace it before it stops the car from working. New subscriber

[scotts.]

THIS was very helpful! Car wouldn't start this morning, presenting like a dead battery. Tested the voltage per your directions and was reading 12.46. Jumped it to get it running and tested again and it went up to 12.47, tested the voltage at the Alternator per your directions and it was reading 14+ volts out. Ended up being dirty terminals...cri$i$ averted. Thank you for the clear instructions.

[Djm]

Ty for the video helped a lot do you have a video on checking the starter

[dcook]

Thank you sir! I was gonna replace the alternator because the battery is only a year old with a 1000cca. The battery reads 12.5 but won't start after a jump the alternator is 14.6 and battery is around the same with vehicle running so I'm thinking the battery and Michigan cold weather. Thanks. Subcribed

[andrewmiller]

Thanks for replying sir. I tested the way you did and the alternator puts out about 1.45v that's what showing in the multimeter set to 20v looks like I have to replace it.

[andrewperera]

Good video. when testing the alternator your meter showing 11.7v if the alternator is good what's the reading would be above 12v??.

[neld]

What should it read when testing the alternator? Where should it be to know it’s good?? Thanks in advance

[Zeltroix]

Yep my alternator was charging at like 11.5V, I had just changed the regulator on it about a month ago, was charging at 17v! Was working good for a while. Guess it's time for a new alternator, do you recommend any brand?

[AlwaysLearning]

Battery sitting at 11.8 but started. Volts at battery dropped to 9.8 when stareted without any extra load. Saw your video but now won't start. Getting battery checked and charged. I will do the check at the alternator once I get it started. If I'm still getting under 10V at alternator do I need to check for anything else, or can I assume it's the alternator.

[eeyyaakk]

Hi friend
positive probe on the stud on the alternator, negative probe on alternator case?
Thank you

[hemordroidnz]

I have a 2008 Jeep Patriot with a new battery, just went for a long drive and the battery light kept coming on, (one time all the lights came on briefly) when either taking off from a stationary position or high revs going up hills. I turned off all electrics and still the battery light came on. Carried out your check and the alternator is charging up to 1400 v . any idea what could cause this? any help is appreciated thanks 👍

[eeyyaakk]

Hi there

1. You were able to start the car even when the battery was below 12 volts. I didn't know that was possible. I'm working on my car right now and I can't turn the engine with the battery at 12.10 volts. Are there multiple factors at play here? Forgive my ignorance, I'm not an expert.

2. If I disconnect a new or working battery from the car, can I expect it to retain at least 12.6 volts for several weeks or is it normal for the battery to gradually go below 12.6 even when it's not connected to anything?

[whocares]

So if I check the alt fire and ground it to the alt and it's like 11.7 is that 100% bad alt?

[radoslavnashev]

Hi, there.My battery shows 14, 87.when I started the car the battery drops to 13, 37v and going down slowly, do not understand how come battery is at 14, 87, I had to turn the lights to take the top layer electricity that build up and went down to 14, 37.still more voltage on battery than ussual