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Hi, last week my alternator died, so i change it. After the crazy replacement (no room to remove it) i Check the voltage and it was all over, 13 to 15 volts not the stedy 14,5 that it should. So i check and clean all the ground, the one from battery and body, and engine to body. No change so i change the battery, and no change. I drove it for 4 days and monitor the voltage, no improvement so replace the alternator again and now i got the same problem, voltage stil not stable. Do you got a idea for me? Thanks
My santa fe is 2011 v6 3.5l
The alternator are rebuilt one
 

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Did you ever check the voltage of the original alternator before it died?

I'd guess a 2011 engine will have a "smart charging system" meaning the voltage output of the alternator is controlled by the engine PCM and isn't necessarily clamped to 14V like it would be on an older type alternator with a "dumb" internal regulator. What your seeing is probably normal for that engine/charging system.
 

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No i did not check my voltage of the old alternator before he died. But i check the one of my freind that have the same model and year like me. Is voltage is stable. The alternator have the regulator in it , i check and i didnt saw any info about the pcm controling the voltage on a santa fe.
 

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i check and i didnt saw any info about the pcm controling the voltage on a santa fe.
Does your car have a battery sensor on the negative battery terminal? It's a little black box with a two wire connector plugged into it.
If so, the engine has a smart charging system meaning alternator output is controlled by the engine PCM.


Info About PCM Controling Voltage On a Santa Fe.

 

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Discussion Starter #5
Thanks for the info. So it could be a ecm problem, is There a way to check that ?
 

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There a way to check that ?
Yeah, I'm sure there is. But you'll probably need a proper diagnostic scan tool to do it. I doubt a cheap generic OBD tool will show you the data pids relating to the alternator.
 

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I tried to unplug the black connector on the negative side of the battery, and noting change. I found the variable charge motion actuator (vcma), i dont know if its the thing that control the alternator but i tried also to unplug it and nothing change. So i am a litle bit confused to where to go next.
 

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Does your car have a battery sensor on the negative battery terminal? It's a little black box with a two wire connector plugged into it.
If so, the engine has a smart charging system meaning alternator output is controlled by the engine PCM.


Info About PCM Controling Voltage On a Santa Fe.
Charging System info attached
 

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Odds are that sensor along with the smart part is controlling the output. I have seen a different vehicle which it has gone to 13.3VDC on my lighter socket DVM.

On it I did a load test of my own making used for decades!!

Engine running with DVM across the battery posts. Note DC volts.
Now one at a time start turning items on and observe the battery DCV
- Headlights
- turn on Highbeams
- Fog lights
- Blower to the Max (Hi)
- Rear window defogger (this is a high draw item)
- Stereo but I would not crank it to the max. you could blow a speaker or the amp. Just loud enough above the norm
- Toggle a power window or two up/down

Now you're running pretty much everything at once your alternator would have to manage. If the Volts are a tad low and well below 14VDC increase the RPM's above 1000 but not more the 1500 and it should come up.

Alternators were designed decades ago to generate their full output around 1200 RPM's. Maybe that's changed but if its doing it job to run all that at once. I would not be changing it. I didn't in the vehicle I was referencing and watch my DVM in the socket now and then when driving. It must have a smart sensor circuit as well.
 

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I too see voltage less at the lighter socket. I blame this on the harnesses dropping voltage and not a true indicator of the actual battery voltage.
 

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Hi, last week my alternator died, so i change it. After the crazy replacement (no room to remove it) i Check the voltage and it was all over, 13 to 15 volts not the stedy 14,5 that it should. So i check and clean all the ground, the one from battery and body, and engine to body. No change so i change the battery, and no change. I drove it for 4 days and monitor the voltage, no improvement so replace the alternator again and now i got the same problem, voltage stil not stable. Do you got a idea for me? Thanks
My santa fe is 2011 v6 3.5l
The alternator are rebuilt one
Sounds normal to me, I have left a cigarette lighter voltimeter plugged in for fun just to understand how it worked before with my car and this sounds like typical behavior. In my opinion, after reading this thread, it sounds like you're chasing after a problem that doesn't exist. If your accessories have enough power to work and your battery isn't dying, then your alternator is working fine.
 

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yes, i know its probably normal the voltage i see , but what is not normal is that all my light (head, map, break....) are not stable. when they are on with the car not running the brigthness is stable, but when the car is running the brigthness varies with the voltage i see on my meter.. thats wy i think the alternator still no good.
 

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You will want to check, clean and meter at the alternator output and various points of the cable end (starter or wherever it goes ) input to the power distribution box. Also ensure your alternator has a good ground, normally done through the mounting bolts. Metering to isolate the point where its seen.
 

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You will want to check, clean and meter at the alternator output and various points of the cable end (starter or wherever it goes ) input to the power distribution box. Also ensure your alternator has a good ground, normally done through the mounting bolts. Metering to isolate the point where its seen.
While I agree with what trip here says I would add that doing a voltage drop test across the connections he mentions would give you a better picture of whats happening
 

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yes, i know its probably normal the voltage i see , but what is not normal is that all my light (head, map, break....) are not stable. when they are on with the car not running the brigthness is stable, but when the car is running the brigthness varies with the voltage i see on my meter.. thats wy i think the alternator still no good.
Keep in mind I drive a different car than you, but my 2013 Elantra GT will run any voltage it wants to during operation (12.7-14.6 volts) unless either of the following conditions are met:
1) My headlights are on
2) My fan blower is set to max speed
During those two situations, the car will switch to 14.0-14.2 volts. It will try it's hardest to stay there. If I turn on every electrical accessory (defrosters, seat heaters, fog lights, accessory ports, etc.) then I can get the voltage to start dropping.

I can see the bulbs shift when the alternator goes back and forth, but it doesn't switch frequently. If i'm not playing with the blower fan or headlights, then it will switch back and forth every 30-60 minutes. I imagine the operation of your vehicle should be similar.
 
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