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VR or stator or both?

C

cfiiguy

Banned
been having an interesting voltage problem that has me seriously considering the sale of my 99 UC.
after the bike has sat for a few hours,when first started it showes 14.5 at the battery. just as it comes off high idle it will drop to what ever the battery is. i have pinned out the stator and it shows 65 vac at 3k, and the oil doesn't stink. i have ohm'd out the stator and checked for grounds, both testing good, so i don't believe it is the stator. also when the voltage drops i have checked accross the CB and checked it with the bike not running and it appears to be good. to help eliminate the CB i have used a jumper accross it. checked and cleaned the grounds. load tested the battery using an old fashion coil tester type. battery shows good. this seems to leave the regulator only, but it was new 5k miles ago and all the tests from this site have shown it to be ok. (light to ground and then to each post of the regulator) checked it with a meter as well set to as low as 50 milliamps with no voltage shown.
has anyone ever seen a regulator act this way? what else can i check? any thoughts or ideas would be great!
also has anyone switched to the 3phase replacement stuff, and was it worth the cost? i run a LOT of "extra" lights. (saddle bag guards,tour pak,front fork covers, you get the idea.)
THANKS
 
Hopefully Hoople will chime in. HE IS THE MAN on this stuff.

But I would replace both.

TQ
 
cfiiguy said:
i run a LOT of "extra" lights. (saddle bag guards,tour pak,front fork covers, you get the idea.)
Click to expand...

You ride the bike and then the battery doesn't have the power for a hot restart? You don't have the charging current for all your extra lighting loads while at idle? What is the reason your working on it.

You said you have added a LOT of extra lights on your bike. Are the extra lights you added controlled by an independent switch. Before I replaced anything, you need to measure the current draw of this extra electrical load on the bike using a current shunt or induction current probe. That is a "must know" number.. That number could be anything from 5 extra amps to 20 extra amps. One you can fix, one you can't. There isn't a large window for error on single phase systems while running at idle..

How I understand it, at 1400 RPM (high idle) you read 14.50 volts at the battery using a quality meter and then at idle (900 RPM) the voltage falls to 12.60. If that is the case, what happens if you bring the RPM back up to 1200 RPM, does it read 14.50 volts again. What is your idle RPM set at?
 
i purchased the bike this way,(extra lights) some are on the acc switch but most come on with the ignition switch. i am afraid my skills don't allow for the measuring of the extra draw. i wouldn't know where to start.
i'm working on it because for most of the summer my volt meter show'd 13 + and then started to show 12 at best. in town riding it would show 10 or less.
i replaced the stator and VR in sept of 2011 shortly after buying the bike. (actually the local HD shop replaced them.)
something has obviously changed.
once the voltage drops, no amount of rpm will restore them. however,the stator output varies from 20 vac at ildle to 65 vac at 3k rpm. i am checking the stator with push pins shoved thru the wire and still hooked to the regulator.
my hot idle is set to 950rpm.
i guess there are 2 main questions for me.
one: can a VR act this way. i have always assumed they were good,or bad. no middle ground.
second: would converting to a 3phase system help? i'm not against doing that if it makes the bike more dependable.
THANKS
 
In post 1 you used the words "when first started it shows 14.5 at the battery". "At the battery" for me means your using a quality hand held digital voltmeter right at the battery terminals. Then in post #3 you said "volt meter show'd 13 + and then started to show 12 at best. in town riding it would show 10". This means your using the built in HD meter on bars.

You can't compare the two. You can't rely on the HD meter regardless of past readings when you first purchased the bike. Once your electrical problem is understood and repaired, then you can go back to using the bars meter while riding. That's OK to do once you know for sure the charging system is doing it's job.

The difference between overcharging a battery and undercharging a battery is only 2 volts. I would never make a decision to change an expensive electrical part based on a factory installed dash gauge, regardless of what it used to read. For any electrical tests, you must use a handheld meter.

To answer your questions: "can a VR act this way". Yes, anything is possible. But it would be very remote. If the VR is limiting the maximum charging voltage (which yours is doing as quoted in post #1), then for the most part, the VR is doing its intended job. The chances of this being your case,, 1 in a 100.

"would converting to a 3phase system help?". Certainly. But only if the root cause for your original problem has been identified and repaired.
For example, lets say your main CB was bad. It's OK when cold but after it warms up, it injects resistance in the charging circuit so the battery won't charge to peak.
Will converting your charging system to 3 phase help with this problem? No, not at all. Your battery and voltmeter will still show low. A simple poor connection defeats the entire benefit of converting to 3 phase.

At this point I am not convinced your VR is bad. See if you can perform this test using a quality handheld digital voltmeter. Set meter range to 20 volts in order to read down to 1/100 of a volt.
Directly at the VR, insert a thin straight pin through each output lead. With engine running, measure the voltage from the positive pin to the positive terminal of the battery. Record the value.
Now measure the voltage from the negative pin at regulator, to the negative post of the battery. Test at both idle speed with all lights ON and also at 2500 RPM with all lights on. No single recorded number should exceed 2/10's of 1 volt.
Don't ever let the pins touch each other or touch ground.
 
i will run those test and see what happens.
when i say at the battery i am referring to checking at the battery with my simpson meter. when i say at the gauge i mean that the cheap harley gauge is showing something other than the "normal". i don't rely on or trust the HD gauge, but it is a visual cue to what is happening in the charging system.
thanks for the help and as soon as i get the numbers from your test i will post and let you know.
THANKS

Hoople
haven't forgot you, just the weather turned to, well you know. priorities have shifted for a little while from the shop to home. i will get to the tests,and when i do i'll post them up here.
THANKS
 
Last edited by a moderator:
cfiiguy said:
i will run those test and see what happens.
when i say at the battery i am referring to checking at the battery with my simpson meter. when i say at the gauge i mean that the cheap harley gauge is showing something other than the "normal". i don't rely on or trust the HD gauge, but it is a visual cue to what is happening in the charging system.
thanks for the help and as soon as i get the numbers from your test i will post and let you know.
THANKS

Hoople
haven't forgot you, just the weather turned to, well you know. priorities have shifted for a little while from the shop to home. i will get to the tests,and when i do i'll post them up here.
THANKS
Click to expand...

just wanted to let everyone know it was the reg. talking to a friend and he has the same bike, in our conversation he mentioned he had removed his black VR to replace it with a chrome one. so i swapped out the VR and fired the bike to see 14.4 on my multi meter. i did this b/4 running hooples test (sorry) but at least it appears the problem is fixed. i would like to know why a brand new harley VR only lasted 5k miles. guess we will see how long this one last. THANKS all, especially Hoople for the help!!!!!
 
cfiiguy said:
just wanted to let everyone know it was the reg. talking to a friend and he has the same bike, in our conversation he mentioned he had removed his black VR to replace it with a chrome one. so i swapped out the VR and fired the bike to see 14.4 on my multi meter. i did this b/4 running hooples test (sorry) but at least it appears the problem is fixed. i would like to know why a brand new harley VR only lasted 5k miles. guess we will see how long this one last. THANKS all, especially Hoople for the help!!!!!
Click to expand...

It is possible H D had a bad run of regulators, Heat, bad grounds and vibration are the biggest destroyer of regulators
 
Its also possible that you haven't found your problem yet.
 
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