GL1200 Limited - overchrging

[BB Goldy]

Hi Guys
My LTD’s charging is on the fritz
Volt meter flashing 16.0 v while at higher speeds usually going back down to the normal 14-14.2v at lower speeds.
Ordered a new Regulator-rectifier on Ebay.
Looking for a plug&play solution if there is any?
Thank you
BB

[Rednaxs60]

Second time today reading about '85 Limited Edition RR. What RR did you order? Have you tested the stator for correct output in AC volts? Make sure the new RR has two connectors, similar to what is installed on your bike. The new RR may only have 5 wires at the connectors, three yellow statr wires (must have), one red power and one black ground. See my explanation in this thread: viewtopic.php?f=5&t=63868

Good luck

[DenverWinger]

With engine running at 3000 RPM measure the voltage between the black wire (sense wire) at the regulator and the battery Pos terminal. if it's any more than a half-volt or so that may be the cause of the overcharging.

The black wire comes from the ignition switch, and the voltage on this wire is what the regulator uses to determine how much current to output. If there's voltage drops on this sense line due to old connections and other accessory loads on the ign switch it can fool the regulator into thinking battery voltage is lower than it actually is, and so the regulator outputs more (too much) current to compensate.

You actually may not need the new regulator at all. There's a way to bypass the sense line from the ignition switch using a relay, so the regulator can measure actual voltage right at the battery. If you read any more than 0.5 volt between the regulator black wire and battery pos terminal with engine running at 3000 RPM your bike is a good candidate for this relay fix.

[BB Goldy]

Thank you guys
I now understand I may have ordered a non LTD compatible RR...
I will do the voltage check at 3000 rpm and want to learn more about the relay fix.
Is it that EC harness from Electrical Connection I’ve been reading about?

[DenverWinger]

Thank you guys
I now understand I may have ordered a non LTD compatible RR...
I will do the voltage check at 3000 rpm and want to learn more about the relay fix.
Is it that EC harness from Electrical Connection I’ve been reading about?

No, you have to wire it up yourself using a relay from the auto parts store to bypass the black wire from the ignition switch and have the regulator measure voltage directly at the battery instead. Very easy to do.

So measure the voltage drop and report back. Will explain further if this sounds like a good fix.

[BB Goldy]

Denverwinger
Pardon my non-electric background (just a dumb banker here...) wanted to make sure I understand:
Do I need to pin-prick the black cable, touch on it’s plastic sleeve or expose from the source?
Positive battery terminal is easy enough to connect to
Thanks

[DenverWinger]

You might be able to get your meter probe to fit alongside the black wire where it goes into the connector at the regulator and make contact with the wire's connector terminal inside the plug. But if you can't get a reading that way, you can get your meter reading from a pin prick into the black wire.

Meter's positive lead to the battery "+" terminal, negative lead to the black regulator wire.

Reading should be on the order of 0.25 to 0.5 volt, but could be as high as a couple volts. That's what we're trying to find out.

[BB Goldy]

Thanks
Will do and report back

[BB Goldy]

Got everything ready for this test
Just want to make sure this is the black wire we are talking about(see pic below)

[DenverWinger]

Yup. Looks like you'll be able to get the meter probe in there right at the tip of the arrow.

[BB Goldy]

Alright
So with the engine off making the connection shows 13.17 volts.
Running the engine at 3,000-3,800 rpm and it’s showing .01 volts just about zero volts.

[DenverWinger]

Well, that pretty well rules out voltage drops to the regulator sensing line as cause of high voltage. I'd have expected more like 0.25 volts though, maybe a volt meter connection came loose while testing?

What meter are you getting the high readings on going down the road? Meter mounted on the bike?

Might check it against the meter you just did this last test with, meter on bike might be inaccurate.

If the two meters agree, and you still have high voltage then I'd say to put the new regulator in.

[BB Goldy]

Yep
It’s the LTD’s stock voltmeter next to the radio
I ran the test twice and I’ll do it again on video and upload to YouTube so you can see the full picture.
Thanks for all your patience

[BB Goldy]

Got the whole process on video
Please note the bike’s voltmeter is not going pass 13.9 volts and the voltage is within acceptable limits(this time showing 0.17 volts) on the sensor check.
Just like the Pink Floyd song I guess the bike has ‘momentary lapse of reason’ when hot
Here it is:

   Never miss a video: Subscribe to the GoldwingDocs YouTube channel today!

[DenverWinger]

13.9 is a good charging voltage...So I'd expect a low voltage drop reading at the regulator "sense" lead. 13.9 at the battery with an 0.17 volt drop at the regulator means it is regulating at 13.7 volts.

The trick is going to be catching the bike when it is overcharging. If the regulator is working correctly it will put out whatever current needed to maintain 13.7v at that black wire.

The black wire comes from the battery thru fuses, some connectors and the ignition switch. But so does a plethora of other stuff. So the voltage drop on that feed to the regulator is dependent on what accessories, lights, fan etc are running, and the quality of all the fuses and connections in between. So if something loaded the power at the ignition switch to be 2 volts less that what the battery is, that would cause your 13.9 battery volts to show 11.9 volts at the regulator. The regulator would increase the power output to the battery until the voltage on the black wire was at 13.7 again. That would increase the voltage at the battery to 15.7 volts to compensate for the 2v voltage loss.

Does that explanation of what we are looking for make any sense?

Voltage regulators usually either work correctly, or they quit. So if your overvoltage is intermittent, might be an intermittently bad connection somewhere.

See if you can rig up a way to have your red voltmeter on the bike connected up this way and go for a ride. If the bike voltmeter start to show overcharging switch on the red voltmeter and see what it says then.

[Rednaxs60]

Have you tested the RR to determine if it is good. Did the test on the same RR as you, Shindenegn SH574A-12, before I installed the external alt mod on my '85 Limited Edition.

This is a thread I posted regarding testing of the RR: viewtopic.php?f=5&t=40801

Good luck.

[BB Goldy]

Great stuff
Thank you guys
My bike has no extra lights or accessories other than stock.
I’m thinking this through about when the 16.0 volts flashes and it may have to do with the radiator fan turning on.
I’ll rig everything out and go for a ride and do the RR check.

[Rednaxs60]

The rad fan turning on should not make the charging system voltage increase. You should see a decrease in the system voltage. To see an overcharging to 16 volts is for the RR to be faulty, it isn't shunting excess power to ground and the RR internal sampling/comparator circuit and reference voltage is not working:

If all components are working correctly, should never see above the RR reference voltage of approximately 14.2 VDC.

[DenverWinger]

The rad fan turning on should not make the charging system voltage increase.

Unless there's a significant voltage drop under load between the battery and ign switch. This would cause the RR sense voltage to go low, and the RR output to battery go high.

[BB Goldy]

The rad fan turning on should not make the charging system voltage increase. You should see a decrease in the system voltage. To see an overcharging to 16 volts is for the RR to be faulty, it isn't shunting excess power to ground and the RR internal sampling/comparator circuit and reference voltage is not working: Shunt-regulator.jpg If all components are working correctly, should never see above the RR reference voltage of approximately 14.2 VDC.

Yes
That is exactly the norm - 14.1-2 volts running at highway speeds than out of nowhere these voltage rises/fluctuations.

[Rednaxs60]

My vote is the RR is the issue. The stator output is determined by engine speed. The electrical system voltage is the RR. Do a check of the RR and the RR diodes as well.

[BB Goldy]

My vote is the RR is the issue. The stator output is determined by engine speed. The electrical system voltage is the RR. Do a check of the RR and the RR diodes as well.

I looked carefully at your RR thread and that British video.
I have almost zero electrical background so I’m thinking if I can snap out the RR with it’s 2 connectors and test it like the are showing I’m fine but if I need to unthread the wires and dive deeper I may do more harm than good.
Thanks again

[BB Goldy]

Ruled out the fan scenario as I took the bike out for a short ride (without the faux tank on)
Not more than 90 seconds into the ride without warming the engine at all the 16 volts flashes kicked in.(so not a hot engine issue)
The fan did not kick in yet.
It ran it’s ‘wacky’ cycle not more than 20-30 seconds going back and settling on 14.2 volts as I headed back home.
Short 3-4 mile run just to better get a handle on what is happening.

[DenverWinger]

What did your voltmeter on the Black Rec/Reg wire say while the voltage was "wacky"?

[BB Goldy]

What did your voltmeter on the Black Rec/Reg wire say while the voltage was "wacky"?

That will be the next step
Riding with the external voltmeter jerry-rigged