How to test alternator?

[mjmarovi 8]

So basically as the topic says, I think my alty is going out. It is causing some whining background noise, and I know all grounds are good, and rca's are clean. I remember having the problem when my old alty when out, and when I got the new one the background noise went away.

Any ideas on how to test the alternator? I know you can disconnect battery after vehicle is started, but that it will really only test complete failure...

[CrazyKenKid 64]

well either pull it out and take it to a shop and let them look at it!

or maybe get a clamp meter and see what kind a amps it is out putting! if it is a constant amperage or if it is all over the place.

other then that i knew when my alt was bad when i noticed my voltage on my batteries was all over the place and very low at full tilt! so i jsut got it replaced. but if you are already on your second alt and getting ready for a third....something isnt right there? my original alt lasted me about 200,000 click and my new one is still going strong nearly at 300,000 so ya. ( i got the car around 98,000 so if he did any work i don't know)

[WrenchGUy 0]

well either pull it out and take it to a shop and let them look at it!

or maybe get a clamp meter and see what kind a amps it is out putting! if it is a constant amperage or if it is all over the place.

other then that i knew when my alt was bad when i noticed my voltage on my batteries was all over the place and very low at full tilt! so i jsut got it replaced. but if you are already on your second alt and getting ready for a third....something isnt right there? my original alt lasted me about 200,000 click and my new one is still going strong nearly at 300,000 so ya. ( i got the car around 98,000 so if he did any work i don't know)

If you have diagnosed all causes then its probably ripple from the alt. Bad diodes in alternator. Just have it checked out.

[mjmarovi 8]

that's what I thought, thanks wrench.

crazykenkid- first alternator was stock OEM and it was pushing battery bank of system of 4 thousand watts, I didn't expect it to last. This alternator was a small upgrade, and pretty sure it was used or refurb or something, I plan on purchasing an Ohio Generator by Christmas, but was hoping this one would get me by till then.

[slim2fattycake 85]

mechman and dc power alt > OG

[djphilly 11]

mechman and dc power alt > OG

[CrazyKenKid 64]

that's what I thought, thanks wrench.

crazykenkid- first alternator was stock OEM and it was pushing battery bank of system of 4 thousand watts, I didn't expect it to last. This alternator was a small upgrade, and pretty sure it was used or refurb or something, I plan on purchasing an Ohio Generator by Christmas, but was hoping this one would get me by till then.

lol that makes sense why it died lol!!

[bigrank916 72]

Cant speak for DC power, but have heard great things. Mechman, on the other hand, I can speak for and say it is very reliable and provides mucho power. A little too much for me lately!

Edited November 6, 2009 by bigrank916

[mjmarovi 8]

Cant speak for DC power, but have heard great things. Mechman, on the other hand, I can speak for and say it is very reliable and provides mucho power. A little too much for me lately!

I'll have to look into those...the Ohio is like $450 but I know it's a great alt

[slim2fattycake 85]

Wow, if you're going to spend 450 then talk to mechman and call Rob at DC power.

[bigrank916 72]

Cant speak for DC power, but have heard great things. Mechman, on the other hand, I can speak for and say it is very reliable and provides mucho power. A little too much for me lately!

I'll have to look into those...the Ohio is like $450 but I know it's a great alt

The Ohio is no sloutch either. I had been recommended Ohio gens many times but they were a little too pricey. I bought my Mechman Rhino series for $299 on sale but I imagine they all are around the $400 mark depending on your vehicle.

[mjmarovi 8]

Yeh, I have seen Ohio's proven in the lanes, and have gone through a couple good conversations with the guy that builds the alty's. He did a very good job explaining to me difference between their alternator and other's alty's. basically, it seemed to me his 200a alty at most rpm levels would give better results than other company's 300 a alty's, and also have a longer life. not saying there aren't other great alty's out there, as I'm sure there are, but we dicusses some kinda well-known alty's like iraggi and those green monsters and a few others...