Last month I noticed when my engine was at normal running temp my voltage would drop to below 12 volts at idle. Would go to just below 13 volts between 2000 and 3000 RPMs. Twice the cel and battery light came on. Took it to the dealer and they changed the stater, rotor and regulator. Still when hot the voltage would drop to 12 volts at idle. I always ride with the passing lights on. I turned them off and the volts went back up to 14. Battery is 4 years old reads 12.83 volts and 10.8 when cranking. Any body have an idea what is causing this? TIA....

Trucky911

 

Sounds like your charging system is marginal at best. Have a look at the voltage regulator and stator. There are diagnostic proceedures in the stickys section.

My guess would be a weak/faulty voltage regulator...if your volt meter is accurate.

 

Trucky ... What bike do you have? Sure would help to know this before considering issues.

But ... if I was to make an educated guess ... with the entire system replaced... I'd have to ask if the battery has been load tested yet?

I would consider a main battery cable connection is not making good contact at it's connecting points. This could be at the battery or where those cables connect to the starter solenoid (positive) or chassis (negative).

And Did you have the Stator, Rotor and Voltage Regulator tested before removing them, or did someone just decide to throw parts in hoping it would cure the issue?

My old EVO was in perfect shape after I replaced the Stator and Voltage Regulator due to a bad (burned and damaged) Stator, and then I was still having issues ...but ... until I added a secondary ground lead from the frame where the regulator mounts to the actual motor I still had issues.

Also why replace the rotor? Unless the magnets are loose, or you are upgrading to a higher amp system they don't go bad.

Odds are good it's the ground connection to the frame that needs removing and both the frame and the connector need to be filed / sanded so there is bare metal to bare metal contact being made. Too often there is corrosion between connections that reduce the charging voltage going to the battery.

Good luck .... hope this helps!

 

nhrider1 & JohnnyC thank you for your replies. The bike is a 2006 FLHTCi w/ 65,000 miles. Stage 1 A/C, slipons and Andrews 26g cams and thundermax w/ autotune. The work was done at the same dealer that replaced the same parts 4 years ago. The bike had the same systems back then. I checked the primary oil before I took it in. It did stink. I drive with my passing lamps on all the time. The other day I shut off the passing lamps when I noticed the voltage dropping when engine was hot. Went for about 70 mile ride today w/ passing lamps off and the voltage dropped to 13 volts at idle with the engine hot. Turned passing on and voltage dropped to below 13 volts. Went right back to 14 volts as soon as I took off from a stop. These are the same systems after the stator was changed 4 years ago. I have a new battery coming on Thursday. Gonna check the battery connections and grounds also. Other wise bike runs good.....Hope this helps more....
Thank you,...........

Trucky911

 

Odds are good it's the ground connection to the frame that needs removing and both the frame and the connector need to be filed / sanded so there is bare metal to bare metal contact being made. Too often there is corrosion between connections that reduce the charging voltage going to the battery.

JohnnyC can you tell me where to find this ground?...

Trucky911

 

My work was with my '86 Tour Glide. The ground wire led to a connector on a starter bolt. There also was a braided ground from the chassis underneath the frame that I believe went to a bolt on the bottom of the engine.

Some of the additional lighting will put an unusually large load on the charging system. Most factory acc spots will only work on low beam. If they do come on with your high beam that could be more than the system was designed to operate if you total up the current draw.

I replaced my 2nd factory stator with a Cycle Electric aftermarket stator and matching regulator. The first replacement was OEM and only made it 5K. I also had HD aftermarket spots. Didn't drive too often after dark and limited the run time on them.

I even swapped out my 6 fixture stop lights with LED to help drop the (over) load on the system.

Mine came with 22 amp and I thought the 32 amp upgrade would solve the matter but it didn't.

The Cycle Electric Stator has a higher conductivity for higher amperage at lower RPMs and the coils were rated at higher load temps too. The regulator was a redesign that cut back the load on the stator when charging requirements were less. The HD has a constant load on the stator and shunts off overage to ground. But none of that really matters since you have OEM back in the bike.

I'm uncertain of your systems rated output, perhaps 38 or 42 amps. But if all the lighting puts close to a maximum load on your recharging system it will shorten the life of the Stator and regulator.

You could move to the new LED spots which produce high output of lumens using lower current than incandescent or Halogens.

One last thing that turned out to work and solve my issue of still having lower than expected voltage / amperage for recharging and indicating on the meter. I ran a secondary ground lead from the motor to the mounting base of the regulator. I also used star washers to mount the regulator as it needs a good clean mount and the star washer to bite into the metal to complete the proper grounding of the regulator. Not certain if that additional ground wire has any advantage on your ride but in my case the old EVO's had some quirks grounding the charging system and it's connection to the motor.

 

You are reading this voltage from the dash mounted gauge?

If so, try reading the voltage with a real voltmeter and see if it agrees with the dash mounted gauge.

 

I did that also. Multi meter connected to battery reading 14.2 volts. Turned on the passing lights and voltage dropped to 13.5 volts. Close to what I can see on the dash volt meter....

Trucky911

 

JohnnyC my bill of sale indicates that a 50 amp system was installed both times it was done. I did have a Truck lite phaze 7 in last year. While this light was in I noticed voltage draw was not as great but my radio reception went south. Put the stock head light back in and radio played fine. After i check the grounds gonna check into changing the lights to LEDs. Maybe I should do what I did with my troubled 02 FLHTCi. Came home one day and told my wife I finally got the bike fixed. When she asked what was wrong? I told her I don't know, I left it there and came home with a new bike!!!....

Trucky911

 

50 amps is a good amount.

It sounds like your experience with taking a reading with the multi-meter, and noting a different power drain when you switched your passing lights on was a good understanding of what's going on now.

Odds are good that the load on the battery and recharge system comes from those passing lights. Do you run them in the daytime too?

I don't think there's a need to look any further for trouble. Your gauge is likely showing you a correct amount under high load.

I had an aftermarket radio act up when I ran the spots and put my system under a heavy load. The interference to your radio reception is odd for the alternative, lower load lights. I can't think of any reason for that.

My wife shocked me by sitting in the passenger seat of a brand new 2014 FLHTCU last February. Long story short she bought it. Mind blown!

Take care and let us know how it all works out.