Negative Volts from Voltage Regulator

[Gas Man]

Got Chopper Dave's K9 on the lift. He wanted his charging system checked because he's noticed when hooking it to the tender after a ride regardless of time/miles (1.5hr or 30min ride) it takes a long time for it to go to float. But he never expierences any ill effects to his electrical on the bike. Just concerned by noting the weird battery tender behavior.

So I started to go thru it with my service manual.

Braille Battery at 13.4 volts sitting = Good

Both sides of Circuit Breaker read Battery Voltage = Good

Open circuit when testing stator plug to ground = Good

25 A/C - 50 A/C volts from the stator with engine running = Good

Reading 12.9 volts on the VR side of the stator plug, which is just less than battery voltage = Good

With motor running battery voltage drops to 13.0 volts = ???

Disconnected battery from CB, started bike, and I'm getting rising voltage from the VR. HOWEVER, its reverse polarity (reading negative volts). =====???????

Stator checks GOOD
Battery is GOOD

The VR when disconnected from the battery reads reverse polarity. And when all is hooked up it isn't rising the voltage at the battery.

The manual states "the VR has a built in reverse current protection. This will protect the battery from discharging through the VR..." but with it putting out reverse polarity that makes me think this protection aspect isn't functioning.

All tells me that the VR is junk!

Ideas?
Comments?
Corrections?
Help?
Confirmation?


P.S. Noobs, this is why you buy a service manual for your bike. It allowed me to troubleshoot this problem as I did above. BUY THE DAMN SERVICE MANUAL, for God's sake you bought a $30k bike, you have no excuse!

 

[chihuasbigdog]

Even on a Harley, you dman Chris!!!

 

[alhall88]

CHARGING SYSTEM TESTING

Battery: Turn ohmmeter to the DC Volts setting that can read 12V or more. With your motorcycle off, read from Positive to Negative making sure the Red is +, Black is -- If battery is good you should get about 12.5 to 13.5 volts

Charging: Using same multi-meter range, start the motorcycle and run RPM's up to above idle. Voltage should increase to several volts above initial reading, usually to about 14.7 V. Voltage should not go much higher than 14.7 V. If voltage goes a lot higher when you rev the engine, you could be overcharging due to a voltage regulator problem. If voltage doesn't change, your motorcycle is not charging.

Stator: If your motorcycle is not charging, you need to check the stator. Locate the plug for the stator on the front of the engine block. Switch the multi-meter to OHMS range on the lowest setting, usually 10 ohms. With the motorcycle off, read between the 2 pins or holes in the block. These should show continuity. If your meter is accurate you could read 1 to 3 ohms, but cheaper meters will not be that accurate. As long there is continuity it passes this test.

Now change the setting on the multi-meter to the highest OHM range like 100K. Touch one probe to a pin or hole in the engine, the other to the engine case or a metal bolt on the engine. The meter should not move. Try the other pin the same way and it also shouldn't move. If you get any reading the stator is shorted and must be replaced. This requires special tools and you should consider taking it to a shop. If you get no movement on the meter, it's not shorted out so you need to check for output.

To check for output, change multi-meter to AC Volts setting over 100 Volts. With the alternator plug disconnected, start the bike. Use the probes (not polarity sensitive) to read between the pins or holes in the engine block. You should read about 20V per 1000 rpm's. At idle expect about 25V, as you rev the engine it will increase to 60 or 70 Volts. If it does your stator is OK, if you get no output the stator is bad and you will need to replace it or take it to a shop.

Voltage Regulator: If your stator is not shorted to ground and has the proper output, your regulator is most likely the culprit. If your stator checks out OK but battery voltage don’t increase when the motorcycle is running, the regulator isn't doing its job and needs to be replaced. It's an easy swap; just make sure you bring the old one with you to make sure they give you the correct unit. If the battery voltage goes too high when you rev the motorcycle the regulator isn't limiting the voltage and again it needs replacement.

 

[Gas Man]

Even on a Harley, you dman Chris!!!

Thanks!!

CHARGING SYSTEM TESTING

Battery: Turn ohmmeter to the DC Volts setting that can read 12V or more. With your motorcycle off, read from Positive to Negative making sure the Red is +, Black is -- If battery is good you should get about 12.5 to 13.5 volts

IT WAS GOOD 13.5 VOLTS

Charging: Using same multi-meter range, start the motorcycle and run RPM's up to above idle. Voltage should increase to several volts above initial reading, usually to about 14.7 V. Voltage should not go much higher than 14.7 V. If voltage goes a lot higher when you rev the engine, you could be overcharging due to a voltage regulator problem. If voltage doesn't change, your motorcycle is not charging.

IT IS NOT CHARGING

Stator: If your motorcycle is not charging, you need to check the stator. Locate the plug for the stator on the front of the engine block. Switch the multi-meter to OHMS range on the lowest setting, usually 10 ohms. With the motorcycle off, read between the 2 pins or holes in the block. These should show continuity. If your meter is accurate you could read 1 to 3 ohms, but cheaper meters will not be that accurate. As long there is continuity it passes this test.


I DON'T THINK I TESTED THIS.

Now change the setting on the multi-meter to the highest OHM range like 100K. Touch one probe to a pin or hole in the engine, the other to the engine case or a metal bolt on the engine. The meter should not move. Try the other pin the same way and it also shouldn't move. If you get any reading the stator is shorted and must be replaced. This requires special tools and you should consider taking it to a shop. If you get no movement on the meter, it's not shorted out so you need to check for output.

IT SHOWED AN OPEN CIRCUIT (NO BEEP ON METER)

To check for output, change multi-meter to AC Volts setting over 100 Volts. With the alternator plug disconnected, start the bike. Use the probes (not polarity sensitive) to read between the pins or holes in the engine block. You should read about 20V per 1000 rpm's. At idle expect about 25V, as you rev the engine it will increase to 60 or 70 Volts. If it does your stator is OK, if you get no output the stator is bad and you will need to replace it or take it to a shop.

THIS CHECKED OUT GOOD EXACTLY AS IT SAYS

Voltage Regulator: If your stator is not shorted to ground and has the proper output, your regulator is most likely the culprit. If your stator checks out OK but battery voltage don’t increase when the motorcycle is running, the regulator isn't doing its job and needs to be replaced. It's an easy swap; just make sure you bring the old one with you to make sure they give you the correct unit. If the battery voltage goes too high when you rev the motorcycle the regulator isn't limiting the voltage and again it needs replacement.

THIS SAYS WHAT I THINK AS WELL, VR IS BAD.

MY RESPONSES IN GREEN CAPS

I just want to make sure its the VR before we start throwing parts at it. I have just never even heard of anybody getting reverse polarity from the VR.

The bike is now back at Dave's and I can no longer test it. I'm thinking of ordering the VR and installing it ASAP. Just want more input.

 

[Chopper Dave]

I made it back home around 6:50pm....
hooked bike up to tender...around 7pm was solid red
around 9pm noticed it was blinking green (80%)
those Braille batteries sure are strong!

oh Gas....here are those numbers off the VR

BDM PH 1 5570
REP 15570 00 13
06 095 08 10796

thanks again for your help bro!

 

[Gas Man]

Hey... you do good for keepin an eye on your shit. Most people wouldn't give it 2 looks based off just how the battery tender acts. But you know how your bike is suppose to be and had it looked into further. Like Cutty would say... all aces bud!

 

[alhall88]

Thats kinda what I was getting at there is no real check for the voltage regulator only an elimination of the other components.

 

[DRBarnhart]

Actually, there are some checks you can run on the VR...

Tip of the Week #4
Here is an easy way to test the Voltage regulator on a 2005-2009 if you suspect it is bad. For this test the wire to the battery will be called B+, the two pins out of the stator plug will be called Pin 1 & Pin 2, case will be ground.

1. Disconnect the ground cable from the battery.

2. remove the B+ wire from the circuit breaker.

3. Attach an ohm meter between B+ and ground (by the way the case is clear anodized therefore when measuring ground you need to measure it at the bolts). The resistance should be over 2meg Ohms, or an open circuit depending on your meter.

4. Measure resistance between B+ and Pin 1 or B+ and Pin 2. There should be great than 1megohm, or an open circuit depending on your meter.

5. Measure resistance between Pin 1 and Pin 2. There should be more than 1megohm.

6. Measure resistance between Pin 1 and ground and then Pin 2 and ground. should be greater than 1megohm.

If any of these values are less than specified you have a bad voltage regulator. This is a good test to confirm that it is bad however there has been one time that I did this test, everything measured fine but the VR was still bad. So what this means is if you are less than specified resistance you definitely have a bad VR. If you are not less you may still have a bad VR but should double check the rest of the system before you spend money for a new VR.

Dennis

 

[chaingunner]

Actually, there are some checks you can run on the VR...

Dennis

That is along the lines as I understood it, and doing that, and eliminating the stator and battery from the equation determined my VR was bad. Replaced that and not one single problem since, in fact I haven't had it on life support since. (I will, just haven't)

 

[RRRUFF]

Gas, I think VR is bad. Buddies bike (06 K9) showed similar symptoms with the battery tender. I did all the checks you did but didn't see reverse polarity. With what you are seeing and being an 06 VR, very likely shorted out and doing something weird like this. Let us know what the fix is.

 

[Gas Man]

Thats kinda what I was getting at there is no real check for the voltage regulator only an elimination of the other components.

That's the way I have always known it to be.

Actually, there are some checks you can run on the VR...

Dennis

Good call Dennis. Unfortuantely I can't do this now... may have to bring my meter this weekend when I see Dave and his bike next. But it would be nice to get some parts on order before then.

That is along the lines as I understood it, and doing that, and eliminating the stator and battery from the equation determined my VR was bad. Replaced that and not one single problem since, in fact I haven't had it on life support since. (I will, just haven't)

Yeah Dave had mentioned you just did the same thing.

I checked his VR numbers and he doesn't have one of the bad lemon versions. Its just plain bad I think.

Gas, I think VR is bad. Buddies bike (06 K9) showed similar symptoms with the battery tender. I did all the checks you did but didn't see reverse polarity. With what you are seeing and being an 06 VR, very likely shorted out and doing something weird like this. Let us know what the fix is.

Yeah the reverse polarity threw me for a loop.

 

[Gas Man]

Well Dave got the new VR and we got that installed. Started the bike and that fixed it. Bike was showing 14.0 volts DC at idle and 14.2-14.25 at 2k rpm. And about 14.5 at the upper end of the RPMs. The replacing of the VR isn't hard but the wiring is time consuming.

We re-used the wire loom off the old bdm unit, then I cut off the VR pig tail for future use in diaganosis on bikes.

Should make it easier to trouble shoot and take readings.

As a side note:

He also brought over some new 3 band grips and pegs for his bike. Further, a new starter o-ring to fix his primary leak.

Had some coffee while we did the pegs, took our time going thru the projects, had some pizza and soda that Uma brought home for the boys, then finished up in time for Dave to ride home with confidence and style.

Pullin the side covers and pipes to pull starter to replace o-ring

I wonder what they are doing or looking at here? hmmm

Alhall, Alicat, Sgt, and Dave's bud Doug all came to hang out with Brinks and Logan, but to also join them in making fun of the union shop we were running. :lol: Seroiusly, good to see some of the boys.

 

[Chopper Dave]

Thanks again Gas for all your help!:2thumbs: was good to see Big Al and Alhall again....those new Banded grips and pegs feel alot better than the stockies
Thanks to Uma for bringing back some "grocceries"
yep rode back home 85 miles....no oil leak.....plugged the bike in the tender..and by time I took my jacket off...it was already flashing 80% green:2thumbs:

Thanks again dude

 

[RRRUFF]

AND ANOTHER JOB WELL DONE, BY THE BOYS!:2thumbs:

 

[N8KAM]

AUHHHHH... A Gasman work day without an invite..... I'm Hurt....

 

[Gas Man]

Shit Kam... you are always worldly travelled. Maybe I'll harass you at work to make up for it.... maybe grab lunch...