Am I testing my alternator wrong?

[ForceEdge 10+ year member]

It drops to that at idle correct

No at 2000-2500 rpm. That's why I think there's a problem!

Here's an I'd depth overview of my system

http://www.youtube.com/watch?v=oPHYmlZFGLg&sns=em

Here's a video of my system running with voltage drop

https://www.youtube.com/watch?v=B_F_El-Zd98

 

[Phoenix Risen 10+ year member]

a little voltage drop is normal, what is the idle voltage on that alt?

 

[AndrewH05]

Heated its rated at 290amps which is still PLENTY to run only my 1600rms system. Why does my voltage drop to 13.7-13.9 full tilt?

Did you get a chart with your alternator telling / showing it's power curve? Aka how much it's rated for at certain RPMs? Did you go over your wiring again? I feel bad that you keep having to ask the same question over and over, if you're positive (no pun intended!) that your wiring is good, you need to have that alternator tested to make sure it's actually putting out what it should be. Wish I could be more help but plenty of people have made suggestions and I'm not sure if you're actually looking into the suggestions or if you're just plunging ahead until someone says something that sounds right to you.

 

[CHEMMINS 10+ year member]

It's fawked.....send it back to them and tell em to shove it up their arse and get a Mechman. Mine charges at 15v, and doesn't drop past 14.7 with my grid heater which pulls up to 120 amps.

 

[Trippymane 10+ year member]

13.9V is what the regulator is set at. Which is normal. Your need a load tester (Google carbon load tester) and your clamp meter to determine output.

 

[audiobaun 5,000+ posts]

From the Vids,I noticed that on the Big3, only 0ga was used for the alt only, and not the 2 ground wires(which one was left stock, and the other?Prob 4ga as well)Another thing i did see was that,the ground placement for the amps, is not a solid ground that goes to the Chassis.Looks to me like a spot was chosen to sand down on a sheet metal spot,and not the chassis for a solid ground.remember..these newer vehicles are UNIBODY Vehicles,and SubFramed.still best to ground to a solid bolt that at the least goes to the framing,or a strut tower would be Ideal for the rear location as well if its feasible,or straight to the rearend somehow(sometimes a bolt can be removed and a ring terminal can be used for this location).That what I see in the first vid that I watched.Just my 0.02cents

 

[ForceEdge 10+ year member]

From the Vids,I noticed that on the Big3, only 0ga was used for the alt only, and not the 2 ground wires(which one was left stock, and the other?Prob 4ga as well)Another thing i did see was that,the ground placement for the amps, is not a solid ground that goes to the Chassis.Looks to me like a spot was chosen to sand down on a sheet metal spot,and not the chassis for a solid ground.remember..these newer vehicles are UNIBODY Vehicles,and SubFramed.still best to ground to a solid bolt that at the least goes to the framing,or a strut tower would be Ideal for the rear location as well if its feasible,or straight to the rearend somehow(sometimes a bolt can be removed and a ring terminal can be used for this location).That what I see in the first vid that I watched.Just my 0.02cents

13.9V is what the regulator is set at. Which is normal. Your need a load tester (Google carbon load tester) and your clamp meter to determine output.

It's fawked.....send it back to them and tell em to shove it up their arse and get a Mechman. Mine charges at 15v, and doesn't drop past 14.7 with my grid heater which pulls up to 120 amps.

Did you get a chart with your alternator telling / showing it's power curve? Aka how much it's rated for at certain RPMs? Did you go over your wiring again? I feel bad that you keep having to ask the same question over and over, if you're positive (no pun intended!) that your wiring is good, you need to have that alternator tested to make sure it's actually putting out what it should be. Wish I could be more help but plenty of people have made suggestions and I'm not sure if you're actually looking into the suggestions or if you're just plunging ahead until someone says something that sounds right to you.

I have a zero gauge ground wire that's grounded to the strut tower under my hood. Also have the stock ground grounded to the frame.

It's just weird that with increased rpm my voltage doesn't raise whatsoever.. I have a feeling something's just wrong with the alt. With all accessories on with my amps OFF my voltage is at 14.03 at 2k rpm. Something is obviously wrong guys. I'm just trying to figure it out //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif and no I did not receiver a chart..

$650 on an alt is not something I want to mess around with. :/

 

[Trippymane 10+ year member]

Do u have any friends with bigger amps that can actual put a real load on your electrical system? And your alt has a voltage regulator to keep your voltage as consistent as possible. Otherwise if it didn't and say it charged at 14v at idle then it would over charge and cook your batteries when you increased engine speed/rpm.....

Throw a friends amp in your car that can actually put a load on your alt and then clamp it.

 

[ForceEdge 10+ year member]

Do u have any friends with bigger amps that can actual put a real load on your electrical system? And your alt has a voltage regulator to keep your voltage as consistent as possible. Otherwise if it didn't and say it charged at 14v at idle then it would over charge and cook your batteries when you increased engine speed/rpm.....Throw a friends amp in your car that can actually put a load on your alt and then clamp it.

But my **** stock alt kept it at 14.4 with all accessories on at IDLE. This alternator dips with all accessories on at 2k RPM..

None of my friends have an amp that big. Any place I could take it where they can put a load on it?

 

[Trippymane 10+ year member]

U can go to harbor freight and just buy a cheapo load tester.

500 Amp Carbon Pile Load Tester

 

[ForceEdge 10+ year member]

U can go to harbor freight and just buy a cheapo load tester. 500 Amp Carbon Pile Load Tester

And how will I know if my alt is putting out around 300 amps?

Will the voltage drop severely if it can't handle a 300 amp load?

 

[Trippymane 10+ year member]

Use your new clamp meter... and yes if it can't handle a 300 amp load it will drop voltage.

 

[Trippymane 10+ year member]

Throw ur clamp meter on there hit the maximum button and crank the knob on the load tester.

 

[mlstrass 5,000+ posts]

any belt squeal? Could be slipping. SPX's are pretty strong at idle....

 

[mlstrass 5,000+ posts]

It's fawked.....send it back to them and tell em to shove it up their arse and get a Mechman. Mine charges at 15v, and doesn't drop past 14.7 with my grid heater which pulls up to 120 amps.

Tell that to my buddy who's mechman starting charging at 16-18v...in a 12v set up. Their fix was to make him buy an external regulator...