voltage regulator problem
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Road Master
Joined: Jan 2014
Posts: 1,036
Likes: 25
From: Texas
voltage regulator problem
Took a road trip today, 190miles into the middle of Texas and in the last stretch before getting to my destination, my check engine light and battery light would come on for a few moments when sitting at a light, then turn off once I got under way again. The voltage meter would randomly drop to 8-12 bolts then climb back up to 14. My battery is practically new. There is no dealerships remotely near me except Austin(which will be horrifically busy due to the ROT rally in town) to get it checked out at, so im really concerned wether Its safe to make the long haul back north with it being finicky. No issues came up until I hit stop and go traffic in the late afternoon. Bike still ran fine. Any suggestions?
Last edited by sbeast; Jun 14, 2014 at 02:29 AM.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
less likely VR.
the VR is a limiting device- it regulates DC voltage below 14.8 volts. after converting the AC voltage from the stator to DC.
( a bad VR will allow AC to pass, allow DC voltage above 14.8 or allow current to flow "backwards" from the battery and drain a sitting battery or to not pass current at all---- those are the 4 ways that a VR can fail, a 5th way is if the wire from the VR to the battery is shorting on the frame or 5.5 the wire breaks or "open circuit".
on a late model; the stator should be outputting 16 to 23 volts AC per 1000 rpms ( so at 3000 rpms, you should see 48 to 69 volts AC)
check cables for clean and tight.
( MANY electrical problems are bad connections- simply replacing a part will often "fix" the problem- which was not a bad part but a bad connection. the connection was renewed and secured when the parts were replaced)
don't count out a battery failure- I've had a few "new" batteries fail under me....and a duff battery or battery cable can destroy the charging system.
the complete diagnostics are posted in the electrical section, all you need is a voltmeter.
do not use the in dash for diagnostics, they are unreliable and subject to voltage drop within the wiring harness
emergency "get home" is buy a battery at autozone and tie it to pass seat, buy cables and wire the + to + on your bike battery, and the - to - on the bike battery, or bolt to the frame.
turn off spots, use low beam ( reduce the load... you can even unplug the headlight if you are brave.)
mike
the VR is a limiting device- it regulates DC voltage below 14.8 volts. after converting the AC voltage from the stator to DC.
( a bad VR will allow AC to pass, allow DC voltage above 14.8 or allow current to flow "backwards" from the battery and drain a sitting battery or to not pass current at all---- those are the 4 ways that a VR can fail, a 5th way is if the wire from the VR to the battery is shorting on the frame or 5.5 the wire breaks or "open circuit".
on a late model; the stator should be outputting 16 to 23 volts AC per 1000 rpms ( so at 3000 rpms, you should see 48 to 69 volts AC)
check cables for clean and tight.
( MANY electrical problems are bad connections- simply replacing a part will often "fix" the problem- which was not a bad part but a bad connection. the connection was renewed and secured when the parts were replaced)
don't count out a battery failure- I've had a few "new" batteries fail under me....and a duff battery or battery cable can destroy the charging system.
the complete diagnostics are posted in the electrical section, all you need is a voltmeter.
do not use the in dash for diagnostics, they are unreliable and subject to voltage drop within the wiring harness
emergency "get home" is buy a battery at autozone and tie it to pass seat, buy cables and wire the + to + on your bike battery, and the - to - on the bike battery, or bolt to the frame.
turn off spots, use low beam ( reduce the load... you can even unplug the headlight if you are brave.)
mike
Last edited by mkguitar; Jun 15, 2014 at 05:13 PM.
Grand HDF Member
Joined: Jan 2012
Posts: 4,458
Likes: 2,877
From: Oklahoma
All of the above suggestions are right on and should help determine if it is really the VR going bad. Once all of the cables are checked, your possible VR failure symptoms are identical to mine. Over several weeks and several hundred miles the battery light illuminating became more frequent. As with anything mechanical, it could totally die the next time you fire it up of it could be a minor irritation for several weeks and hundreds of miles. How far away is the next available Harley dealer of independent service outfit? How far from home and how many cities must you ride through? This may be a heat related gradual failure that for right now only shows up when you are in slow moving traffic so if you can keep moving the occurrences won't be as often for a while. As my failure progressed I was always near home so my decision wasn't as tough as yours is. Good luck however you go.
Supporter
Joined: Jul 2007
Posts: 2,196
Likes: 10
From: Shenandoah, TX
Mine was doing the exact same thing two weeks ago. Turned out to be the stator. The stators on the latter models have three fazes, that's so it will fully charge at idle. Mine had one faze burned out. Changed the stator and all is good. Chances are, your VR is still good.
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Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
As Mike points out, go to the Tech Electrical section, where there are two Stickies on how to check your charging system. They will help you identify the culprit.
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Road Captain
Joined: Jan 2010
Posts: 527
Likes: 42
From: Sequim, WA
Took a road trip today, 190miles into the middle of Texas and in the last stretch before getting to my destination, my check engine light and battery light would come on for a few moments when sitting at a light, then turn off once I got under way again. The voltage meter would randomly drop to 8-12 bolts then climb back up to 14. My battery is practically new. There is no dealerships remotely near me except Austin(which will be horrifically busy due to the ROT rally in town) to get it checked out at, so im really concerned wether Its safe to make the long haul back north with it being finicky. No issues came up until I hit stop and go traffic in the late afternoon. Bike still ran fine. Any suggestions?
For what it's worth, my 2012 Ultra fell under the VR recall. I had these issues with the VR that the dealer installed due to the recall. I never had a problem with my original VR.
Good luck!
Last edited by paulhog; Jun 14, 2014 at 05:55 PM.
Outstanding HDF Member
Joined: Jun 2007
Posts: 2,019
Likes: 3
From: St.Pete Beach
Had that on my FLHT, downright sucked trying to figure it out, my bike barely ran and lost all my lights....Had to ride back bumper of a cage for 15 miles on way home from the beach...and it had to happen at dusk....