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Troubleshooting charging problem

24K views 27 replies 12 participants last post by  markfish54 
#1 ·
Am I looking in the wrong place in the service manual?
I can't find a single word in the service manual to diagnose a charging problem in a 2002 FLHTCUI. There's plenty of info on removal and replacement of parts, but no test procedure to rule out a bad alternator or regulator.

Voltmeter at the battery shows only battery voltage, 13 volts, fresh off a charger. Battery is fully charged. No increase when the engine is started.

How do I determine if it's the stator or regulator? I'm leary of disconnecting the alternator when the engine is running to test for AC voltage.

Thanks, John
 
#2 · (Edited)
#4 ·
great info! Thanks guys!

J&P did a nice job with that.

Smelling the oil is a great idea.

Would it have killed the motor company to include that page in their service manual? Instead they nickel and dime you and offer their electrical diagnostic manual for $60.

If it is the stator and/or regulator is OEM the way to go? Or are there better aftermarket alternatives?

Thanks!!

John

Thank you so much!
 
#5 ·
This should help. Someone else wrote this sometime back, I just kept it on file because I found it so helpful.

Whenever you have an electrical problem, always check the source (battery) first... Make sure your fuses are good in the circuit you are testing and both cables are good, no cracks or bare wires thru the insulation and the cables are securely fastened to the battery posts and ground studs with no corrosion... If you have a load tester, you can tell right away if the battery is good or bad... Even new batteries can be bad from the get go...

Once you have checked the source and it's ok then you test the components in the circuit your having problems with, in this case its your charging circuit...

The first "load" check is your stator... Unplug the stator from the regulator... Do not plug/unplug with the ignition switch on...This will damage the regulator... Using a multi meter select continuity... Take one of the probes and touch one of the pins in the plug and the other probe to the frame of the bike; you should see no continuity... If you do, then your stator is shorted out and needs to be replaced... Test both pins in the plug...

Using the multi-meter, set it to AC volts, range at least 60 volts AC.Start the bike while observing the meter... If you have a low output stator (38 amp) then you should see 16-20 VAC per 1000 rpm's... If you have a high output stator (45 amp) then you should see 19-26 VAC 1000 rpm's... Rev the bike up to 2500 rpm's while observing your output... You should see 2.5 times the voltage at idle... Anything under or over your stator is bad...

If the stator checks out ok then turn the ignition off, plug the stator back into the regulator... Take your meter and set it on DC volts, range at least 20 volts... Take your initial reading of the battery with everything off; this is what's called the state of charge... Once you have the initial reading (lets say your state of charge shows 12.5 volts), start the bike and observe the meter... Again, rev the motor to 2500 rpm's... Depending on the state of charge you will see anything from just above what the battery is reading to 15 volts max or, 13 to 15 volts... Anything more or less, your regulator is bad...
 
#12 ·
Using the multi-meter, set it to AC volts, range at least 60 volts AC.Start the bike while observing the meter... If you have a low output stator (38 amp) then you should see 16-20 VAC per 1000 rpm's... If you have a high output stator (45 amp) then you should see 19-26 VAC 1000 rpm's... Rev the bike up to 2500 rpm's while observing your output... You should see 2.5 times the voltage at idle... Anything under or over your stator is bad...
Good info right there, thanks, Mike.

When checking AC output, leave the stator unplugged from the regulator, then measure AC voltage across the stator plug pins, not from a pin to ground...do I have it right?
 
#7 ·
You need a seperate electric manual that covers all models for 2002. A better volt meter wouldn't hurt. With batteries the decimal can tell stuff. 12.7 or .8 is full charge, and about each 10th down will tell you what % of charge.

It should go to about 14.4 when revving it up, dc.

Unplug the stator, connector by the down tubes, above volt regulator. It goes up with RPMs. Can't remember how much. AC volts




If your dc volt at the battery is not going up when revving it, I would unplug stator and check there.
 
#8 ·
Thanks for the help. I had 60 VAC @ 3000 RPM after the stator. So, the alternator is good. After plugging in the regulator and checking voltage at the battery it's obvious there's no voltage coming from the regulator to the battery. I inspected every inch of the cable from the regulator to the battery and the ground. So, the regulator would now like to change its plea to guilty.

Thanks for pointing me in the right direction!

John
 
#9 ·
Nothing else volt regs are a weak point for Harleys, so if you change it, you are better off.

I went with a Cycle Electric, cause lots of people here run them. Only got 20k on it, so I can't say its better. It has bigger cooling fins.
 
#11 ·
The CE is slighly bigger. I have a oil cooler, and one aftermarket oil filter would not clear the CPK. Stock filters do.
 
#15 ·
2002 Manual must be different from my 2000. I have a very good flow chart and diagnose section in my 00 manual. I just had to check my system out, seems I have lots of volts from the stator, but nothing coming out of the regulator. I also have a C.E. regulator on already. Maybe around 30,000 miles on it.
 
#16 ·
04 Ultra Charging Problem

Check engine and battery light. Voltmeter on the fairing shows 8 vdc.

Output of stator is 5vac at 1000 rpm, 10vac at 2000 rpm, 15vac at 3000 rpm, 20vac at 4000 rpm....basically increases 5 vac with every increase of 1000 rpm all the way to red line.

Output of regulator at various rpms all the way to red line is 0 vdc.

Seems the stator output is low...but is it so low that its causing the regulator to not make any DC? Somehow I don't think so. I think the regulator is bad.

What do you think?
 
#17 ·
Check engine and battery light. Voltmeter on the fairing shows 8 vdc.

Output of stator is 5vac at 1000 rpm, 10vac at 2000 rpm, 15vac at 3000 rpm, 20vac at 4000 rpm....basically increases 5 vac with every increase of 1000 rpm all the way to red line.

Output of regulator at various rpms all the way to red line is 0 vdc.

Seems the stator output is low...but is it so low that its causing the regulator to not make any DC? Somehow I don't think so. I think the regulator is bad.

What do you think?
A weak stator will burn the regulator out over time.
 
#18 ·
Stator windings all read good, and open to ground. I can't imagine how the rotor (permanent magnets and all) could go bad. It would have to be either open or high resistance windings, grounded or bad/missing magnets wouldn't it?

I finally found the answer (at least I hope so) in the service manual. It says at 3600 RPM it should be putting out 14.3-14.7 @ 45 amps. Damn book doesn't say if it's AC or DC so I'm not convinced they're talking about the "alternator" output voltage or the regulator output voltage. I should assume, since it's under Alternator system, it should be the AC output of the stator/alternator.
 
#20 ·
14.xx would be DC.

The stator makes AC current. The regulator is also the rectifier. With a series of diodes it converts the AC to DC current. Then regulates the amps to hold the voltage in the desired range.

Stators with low output are usually burned and crispy looking when you get to them. The insulation cooks and then leaks voltage. The VOM does't supply enough current to show the leakage.
 
#21 ·
Like thermodyne says, the stator produces AC current on 2-3 phases depending on which bike you have. Normal output is appx 18vac, per 1000 rpm's if it is producing less, iregardless of the open/ground test, either the stator is toast or the rotor is damaged. Running a low output charging system will damage the regulator, it is a rectifier as well and converts the ac current to DC 13.8-14.2 vdc is normal output.
If you continue to run it you will be replacing the complete system, including a battery, as high or low output will kill the battery.
 
#22 · (Edited)
Looks like you guys might have hit the nail on the head. I've taken the stator out and it looks pretty good. The rotor however leaves me with another question and I think I might know the answer but I'm not sure. Are you supposed to be able to move the magnets around on the rotor or are they supposed to be epoxyed into the correct position? My guess would be they are supposed to be epoxyed in place. If that's the case, would you just replace the rotor or would you do the rotor and stator at the same time? Also wondering if the voltage regulator is really bad or if it's not passing DC because the rotor was shot? I'd hate to order one and not need it. They're not cheap.
 
#23 ·
The magnets are fixed in place and evenly spaced with polarity of the magnets the same' I have glued the magnets back to the rotor. If you use epoxy, and reglue them, make sure you orient the magnets back I, exactly has they came out. Changing the polarity, will cause charging problems. The only way to test the regulator output, is after you have completed the repairs to statorxrotor, recheck the output again, if everything is in specs you are good to go,
 
#25 ·
Damn local dealership doesn't stock the regulator so if I replace the rotor and the voltage regulator is bad too, that's another week of the short New England summer with the bike down. Would you replace the rotor and the stator or just the rotor and see what happens? I also saw somewhere that you could put something in line with the regulator so if the battery goes south it doesn't take the regulator and stator with it. I'm not rich enough to just replace all of it if it doesn't need it but I don't want to have to go back into the primary again if I don't have to. I also noticed some wear on the chain tensioner. Might look into if Haden makes an automatic adjuster for the big twins. I have one in my Sportster. Seems to work well. Thanks for all the help. This is a great forum.
 
#26 ·
I'd look at Cycle Electric. What sucks is rotors are $$$.
 
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