How do you test a voltage regulator?

[Beachrights]

Not getting any charge to battery- not losing charge either while running- only at start does my volts drop. Seeing 12.3 at nonrunning- 11.8 while running- Goes back to 12.3 when stopped. New battery and new solenoid.

All connections look good- what grounds this circuit? maybe i am missing a connection?

How do I test the voltage regulator? I am assuming the generator is good since I have no starting issues.

[victorjohn]

Jack the cart or remove the drive belt. Some cars run when the F/R knob is on N or between the F and R. Using a multitester (voltmeter), rev the engine. Reading should go up to close to 14-14.5 volts. If it reads above 15V, then you are over-charging. (Some VRs can be calibrated to charge just around 14 V.

Release the pedal and reading should be back to just above 12.5 give or take (just a bit above the reading when engine was not running).

If it is not charging, it could be a faulty VR, wiring or starter gen.

[Beachrights]

Did all those tests and now I am at the point of finding the cause of no charge. Do you know how to test the voltage regulator? Can I test the output of the generator to be sure?

As far as I can tell it goes- battery-solenoid-generator-voltage regulator. How does the juice get back to the battery?

[Beachrights]

Ok, found this info- how does it translate to my G9's generators red and green wires?

If you are getting less than 13.5 volts on the battery, take the small yellow wire coming from the starter generator and ground it to the chassis (it has a boot connector near the regulator in the solenoid box). When you ground this wire, you should see the voltage spike to 17-18v across the battery. Don't hold it here more than a few seconds or you could cook the battery. This will test to see if the generator or the voltage regulator is at fault. If the voltage at the battery goes up to 17-18 volts when you ground the wire the voltage regulator is bad

[Beachrights]

Ok, found this info- how does it translate to my G9's generators red and green wires?

If you are getting less than 13.5 volts on the battery, take the small yellow wire coming from the starter generator and ground it to the chassis (it has a boot connector near the regulator in the solenoid box). When you ground this wire, you should see the voltage spike to 17-18v across the battery. Don't hold it here more than a few seconds or you could cook the battery. This will test to see if the generator or the voltage regulator is at fault. If the voltage at the battery goes up to 17-18 volts when you ground the wire the voltage regulator is bad

[pachanga90]

If you have an automotive-style voltage regulator(4-terminal).Disconnect the harness to it.Jump A to F(3 terminals next to each other,jump first and third)Put a meter on the battery and start cart.You should see high-voltage(over 13).If so,the regulator is bad,If not,jump the same terminals at the generator,If this shows 13volts or higher,you have a wiring problem between the 2 components.If you replace the regulator,make sure it is grounded good before connecting the harness(self-grounding so clean the mounting-area of paint/rust)Never connect a loose or hanging regulator,it will fry quickly.Hope this helps.

[Beachrights]

Unfortunately mine is a plug in style- pins so jumping is next to impossible- I am looking for maybe a way to test using the wires that the pin harness plugs into.

Though your info on tight grounding was new to me! I did try to remove the regulator and found it seized- tried penetrating oil still no go. If I have to buy a new one I was going to mount it elsewhere and your info has probably prevented me from frying it! thanks!

[pachanga90]

You can jump it with a paper-clip,done it many times,Just insert the ends of the clip in the sockets in the plug.Just don't grab the clip right-away after you test it,Great-Sadness will follow!You can run a ground-wire to it,if needed to insure a good ground,just use an eyelet connector at one mounting-bolt.

[smallblock450sl]

Might try these tests. The starter/generator will have 2 wires (red and a green) comeing out of the feild case (these are the charge circuit wires) and with an ohm meter, you should read 5 ohms, if not bad charging feild in the starter. You can also check for continuity for the red and green wires (in the harness) at the voltage regulator connection. Also that the black wire has 12 volts negative. Most likely a bad AVR (automatic voltage regulator) or a battery not capable of taking a charge anymore. If you have a budy with a 1990 and up Yamaha gasser car, you can just try there voltage regulator. You should read 14.5 to 15.5 volts when the engine is reved up. Good luck on your charging problem.

[Beachrights]

Smallblock- Good info! Couple of questions- Are you saying put meter on both red and green wires at the same time, meaning positive, negative probes or each individually and ground?

Black wire? Do you mean starter blackwire to battery? Or voltage regulator?

cart will run for about 20 minutes before a no start- slow spin.

battery is new- also have swapped a known good one.