How to test voltage regulator output?

pict1000

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On a Gravely Pro-Turn 148 with a Kawasaki 691V engine I've replaced the voltage regulator because my battery drains after a few mows of my 3 acre lot. The stator is sending 33 AC volts to the new regulator, but the B+ post on the regulator is registering only 11.9 DC volts output (if I'm testing it correctly). Here's how I'm testing it: With my multimeter red lead on the B+ post of the new regulator, and the engine on full throttle, I put the black multimeter lead on the positive terminal of my battery. This is a method I saw explained in another forum. With that I'm getting 11.9 DC volts. Huh!?

This is the second new regulator that is reading that way. I assumed I had bought a faulty new one and tried again from a different vender. But now I'm getting the same results :-(

Is it possible (I seriously doubt it) that I've bought 2 bad regulators in a row? Naaa. What do you think is up?

How should I be testing my voltage regulator/rectifier?
 

bertsmobile1

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B terminal on the rectifier to - terminal on the battery.
+ terminal on the battery to the case of the rectifier
B to rectifier case.
The rectifier needs to be grounded to the mower to complete a circuit.
 

ILENGINE

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With the engine running full throttle connect the red lead to the B+ terminal of the regulator, and the black lead to the negative post of the battery. What is the voltage. Should read battery voltage. Now mow the red lead to the metal housing of the regulator while still keeping the black lead on the negative post what is the voltage. Any voltage over a about 1 volt indicated bad ground to the regulator and battery voltage would mean no regulator ground.

Just trying to make sure you are actually getting battery voltage to the regulator and not just creating a circuit that may not be there, and making sure the regulator is grounded.
 

pict1000

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With the engine running full throttle connect the red lead to the B+ terminal of the regulator, and ...

Just trying to make sure you are actually getting battery voltage to the regulator and not just creating a circuit that may not be there, and making sure the regulator is grounded.

OK great. I will try it out in the morning and post results. Thank you!
 

pict1000

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B terminal on the rectifier to - terminal on the battery.
+ terminal on the battery to the case of the rectifier
B to rectifier case.
The rectifier needs to be grounded to the mower to complete a circuit.

I appreciate the answer very much but I didn't really understand it.
 

bertsmobile1

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Same as what Ilengine said
You need to read between the + terminal on the rectifier to the negative terminal on the battery and also to a ground point like the case of the rectifier.
If your mower has a plastic blower housing and the rectifier is bolted to the plastic housing then it might not be grounded.
The grounding straps get broken or fall off.

If the ground is bad the power terminal on the rectifier will still read 13V between it an the batteryBut if there is no ground then there is no circuit so the amps are sitting there all dressed up with nowhere to go.
 

pict1000

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Same as what Ilengine said
You need to read between the + terminal on the rectifier to the negative terminal on the battery and ...

If the ground is bad the power terminal on the rectifier will still read 13V between it an the batteryBut if there is no ground then there is no circuit so the amps are sitting there all dressed up with nowhere to go.

Thank you for such a thorough explanation! I'm headed out right now to test everything as advised. I'll post my results shortly.
 

pict1000

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And the results are:

With the multimeter set on DC volts, the red lead on the B+ post of the rectifier, and the black lead to the - terminal of the battery, I get 00.0 volts.
With the red lead on the rectifier metal case, and the black lead to the - terminal of the battery, I get 00.0 volts.
With the red lead on the B+ post, and the black lead on the positive terminal of the battery, I get 11.9 volts.
With the red lead on the rectifier case and the black lead on the + terminal of the battery, I get 12.3 volts.
And yes, I have the battery terminals correct in my test.

Any more suggestions would be greatly appreciated!
 

ILENGINE

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Test results show that the regulator is grounded but you are not getting power from the battery to the B+ terminal of the regulator therefore it won't charge. Try running a temporary wire 16 gauge or larger from the B+ terminal to the positive post of the battery and see what what voltage you get when testing the charge at the battery terminals.
 

pict1000

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Test results show that the regulator is grounded but you are not getting power from the battery to the B+ terminal of the regulator therefore it won't charge. Try running a temporary wire 16 gauge or larger from the B+ terminal to the positive post of the battery and see what what voltage you get when testing the charge at the battery terminals.

Ok I will. First I'm going to clean the connection between the positive battery cable and where it connects at the engine (I think it's the alternator). I'll report back in a while. Thanks!!
 
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