Alternator voltage output

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dsrfp

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Hi guys,

Put the multimeter across the battery the other day while the car was running and was getting a reading of 17v +.

Was also getting a 16v + reading at the trailer plug.

When the car is off the reading is 12.5v.

Whilst driving the scangauge is telling me it's running at 14.1v which seems normal.

Does this sound like an alternator issue? Anyone experience the same issue?

Thanks

dsrfp
 
17+ ?? never heard that b4...14.1v is the norm when car is on

buggered multimeter? or set on the wrong settings
 
"If" those volt readings are correct, wouldn't be driving it too much.....

If the ECU is getting those sorts of volts, I'd be worried that some of the internal electronic components would be fried..... Not sure how high a voltage the ECU can withstand though
 
Replace the battery in the multimeter and try again, some times they read high when the battery is getting low.
 
If you've tested the multimeter and it's reading properly, then your regulator is shot.

Anything over 15V on any form of lead-acid battery is lethal. It boils the fluid away rapidly, causing sealed (which despite being sealed, still allow gas to escape under pressure) batteries to become irreparably damaged.

Unfortunately I believe the regulator is part of the alternator. I don't know if a clever auto electrician can remove and replace just that portion of the alternator.

Disposable society. It's gettin' worse.
 
If it is the ALTERNATOR, is there another make of car with a similar Alternator that will bolt stright in? For example, when the Alternators on the early Vitaras/Sierras bugger up, most people just go to the wreckers and buy a EF/EL Ford Alternator for about $70 and bolt it straight in (with a couple minor mods). By doing this u also upgrade your ALT from the crappy 55amp to 110amp capacity..... win win

Is there anything like that, that could be done with the Navara's ALT ???
 
Old.Tony said:
If you've tested the multimeter and it's reading properly, then your regulator is shot.

Anything over 15V on any form of lead-acid battery is lethal. It boils the fluid away rapidly, causing sealed (which despite being sealed, still allow gas to escape under pressure) batteries to become irreparably damaged.

Unfortunately I believe the regulator is part of the alternator. I don't know if a clever auto electrician can remove and replace just that portion of the alternator.

Disposable society. It's gettin' worse.
Click to expand...


Why is the SG reading correct???
 
Krankin said:
Why is the SG reading correct???
Click to expand...

That's a good question. Where's SG get its voltage reading from?

If the multimeter is correct and there's 17V on the battery, why does the SG read 14.1V? Could our ECUs be fibbing to us (I'm guessing that the SG gets its info through the OBD port and that means it's the ECU giving the voltage reading).

So, thinking while I'm typing ... what if the ECU is mis-reading the voltage because of an errant/faulty connection to the alternator and it's telling the alternator to ramp up the voltage?

Just like the chips that "modify" the signal from the fuel rail pressure sensor by using extra resistance to present a lower voltage in the return, what if there's some extra resistance in the alternator output that the ECU is reading that is causing the ECU to make the alternator work harder?

As for replacements - I don't know. There's no indication of the exact model of Navara being used, so I can't get the model number of the alternator out of the manual and search the web for other vehicles that particular alternator (or alternatives) might be in.
 
robmacca said:
If it is the ALTERNATOR, is there another make of car with a similar Alternator that will bolt stright in? For example, when the Alternators on the early Vitaras/Sierras bugger up, most people just go to the wreckers and buy a EF/EL Ford Alternator for about $70 and bolt it straight in (with a couple minor mods). By doing this u also upgrade your ALT from the crappy 55amp to 110amp capacity..... win win

Is there anything like that, that could be done with the Navara's ALT ???
Click to expand...

they reckon a patrol alternator swapover
 
Old.Tony said:
That's a good question. Where's SG get its voltage reading from?

If the multimeter is correct and there's 17V on the battery, why does the SG read 14.1V? Could our ECUs be fibbing to us (I'm guessing that the SG gets its info through the OBD port and that means it's the ECU giving the voltage reading).

So, thinking while I'm typing ... what if the ECU is mis-reading the voltage because of an errant/faulty connection to the alternator and it's telling the alternator to ramp up the voltage?

Just like the chips that "modify" the signal from the fuel rail pressure sensor by using extra resistance to present a lower voltage in the return, what if there's some extra resistance in the alternator output that the ECU is reading that is causing the ECU to make the alternator work harder?

As for replacements - I don't know. There's no indication of the exact model of Navara being used, so I can't get the model number of the alternator out of the manual and search the web for other vehicles that particular alternator (or alternatives) might be in.
Click to expand...


what if the ECU has its own regulator/filter circiutry...I dare say it would, thus the reading of 14.1v at the SG,
but,
the OBD has a constant output regardless of engine/alt output...is the SG reading its V+ from the ECU or dierctly form the OBD???
 
Krankin said:
what if the ECU has its own regulator/filter circiutry...I dare say it would, thus the reading of 14.1v at the SG,
but,
the OBD has a constant output regardless of engine/alt output...is the SG reading its V+ from the ECU or dierctly form the OBD???
Click to expand...

I've no doubt the ECU does, and probably runs on a lower voltage than 12V so that it can operate while the engine's being cranked over too.

But the sensor is supposed to reflect the battery terminal voltage and under most circumstances probably does, most likely taking the reading from the battery output connector on the alternator. This is the connection/interface that I was alluding to as possibly higher-than-normal resistance (= dirty, corroded or damaged).

I'll try mine. I can read the ECU data standing out the front of my car (bluetooth is a wonderful thing sometimes) and can put that and my multimeter side by side. It'll be an interesting exercise.
 

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