Question about Harley Davidson Harley-Davidson Motorcycle Desktop Telephone

1 Answer

Overcharging on a 93 fatboy

Some tell me its the voltage regulator & some say its the do I check if its the stator

Posted by on

  • Anonymous May 23, 2008

    low charging on a 1998 ultraclassic, tested the stator..... 30 AC v at 3000 this low?


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Brigadier General:

    An expert that has over 10,000 points.

  • Master
  • 6,966 Answers


The only defect a stator would have is it's either delivering no or low voltage output. By design, it will always put out higher voltage than required. It is the job then of the regulator to control how much is pushed to the battery. If the battery is overcharging, then the regulator would be at fault.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.

Posted on May 18, 2008

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

How to check charging

If your battery is not good even though you might get a surface charge that is okay it will likely not charge sufficiently to operate the starter and other electrical systems of the bike.

The connection where the alternator stator wires plug into the regulator could be corroded/dirty and need to be cleaned and sprayed with electrical contact cleaner and protected with dielectric grease because corroded wires going to the battery or alternator from the stator or the regulator will affect the ability of the charging system to properly charge a battery.

Initially check the voltage with a voltmeter across the battery posts at about 2000 rpm. If it is between about 14.3 and 15 VDC it is charging okay If it is above 15 VDC you have an overcharging problem which is not being properly controlled by the regulator. If it is charging at less than that you could check the regulator ground first by running a wire from the regulator frame or body directly to the battery negative post and if that does not increase the charging voltage then the ground is okay so next you could check the stator integrity.

To check the STATOR. Turn ignition key switch OFF, then disconnect the voltage regulator connector from alternator stator wiring. THEN connect an ohmmeter set on the RX1 scale with one lead into either of the stator sockets and the other lead to a good ground. And test for continuity - a good stator will show no continuity (0 ohms) across either stator socket - any other reading indicates a grounded stator which must be replaced. THEN remove the ground lead and insert lead it into the other stator socket - the resistance (with ohmmeter still set on the RX1 scale)should be 0.1-0.2 ohms - if the resistance is lower a stator short is indicated. Which means that the stator is damaged and must be replaced. - if the resistance is higher (OL on meter), an open is indicated and again, the stator is damaged and must be replaced. You should check socket 1 to 2 then 1 to 3 then 2 to 3.
Before testing short out the ohmmeter leads against each other and if they do not produce a reading of0 ohms subtract the reading you do get from any readings you get doing the stator checks in order to get accurate stator circuit readings, otherwise you may have out of range reading due to the internal and/or lead resistance of the ohmmeter.

May 30, 2014 | 2003 Harley Davidson FXD Dyna Super Glide

1 Answer

Looking for help charging system not charging battery on 1999 Harley Davidson fatboy

Check regulator ground by using an ohmmeter with one lead on a known good ground, such as the battery ground cable, and the other on the regulator base.
The connection where the alternator stator wires plug into the regulator could be corroded/dirty and need to be cleaned and sprayed with electrical contact cleaner and protected with dielectric grease because corroded wires going to the battery or alternator from the stator or the regulator will affect the ability of the charging system to properly charge a battery.

Motorcycle voltage regulator connections must be clean and tight for proper operation so it must be verified that both the AC (stator) connections and the DC (battery supply side) connectors are clean, fully inserted and locked in place with the regulator latches (they should also be coated with dielectric grease to keep them clean and corrosion free).

The motorcycle voltage regulator is a series regulator that is also a rectifier that changes stator supplied alternating current (AC) to direct current (DC) which the battery system requires. If the charging system does not keep the battery properly charged both with regards to Voltage (between 13 VDC minimum and 15.5 VDC maximum) and the current supply at a high enough amperage to meet the system lighting, ignition, TSM/TSSM, security and accessory requirements plus a minimum of 3.5 more amps (3.5 amps more than the foregoing system requirements) there are a number of tests that can be done to ascertain why.

As the voltage regulator must have a good, clean, tight (and otherwise secure) ground connection for proper operation a Voltage Regulator Ground Circuit Test can be accomplished by connecting an ohmmeter to a known good ground (like the battery negative post) and the case of the regulator. If there is continuity with little resistance the ground is GOOD and nothing more needs to be done BUT if there is NO continuity or there is more than minimal resistance the ground will need to be fixed so there is a low resistance continuity by either locating and fixing the poor ground or adding a new grounding wire from the regulator case to a know good ground.

A Voltage Regulator Power Circuit Test can be accomplished by turning OFF the Ignition, disconnecting the voltage regulator and with an ohmmeter set to the Rx1 setting, testing for continuity between the voltage regulator wire harness supply terminal and the main fuse terminal (with the fuse removed) and if there is continuity present then the wiring circuit here is GOOD but if there is NO continuity then you will need to either find the open and repair it or replace the whole wire running from the voltage regulator to the main fuse.

As there should be no short circuit in the power supply from the regulator to battery (main fuse) wiring OR in the regulator internal circuitry continuity from these both need to be checked again with an ohmmeter set to the Rx1 setting. If the regulator to main fuse wiring connector is not disconnected from the regulator you can connect an ohmmeter with one lead on the regulator supply wire terminal end at the main fuse (with the main fuse removed) and the other lead to a known good ground. If there is NO continuity then you know that both the supply wire and the regulator are okay (as there is no short to ground). BUT if there is continuity then either the regulator or wiring or both is/are shorted to ground. To determine where there is a short circuit (i.e. either the wiring or the regulator internal circuitry) you must disconnect the DC side of the wiring harness (the connector at the DC side of the regulator) from the regulator and test between either or both ends of the wire i.e. from the regulator wire harness.

AC Output Check
Disconnect the voltage regulator connector from the alternator stator wiring and then connect an AC voltmeter across both stator sockets of a two wire stator, or if a three wire stator across two of the three for example 1 & 3 and then later you will repeat the test between 2 & 3 and later between 1 & 2. THEN run the engine at as close as possible in the circumstances to 2000 RPM. The AC output should be approximately 32-40 VAC, approximately 16-20VAC per 1000 RPM. If you have done a stator static test and the stator has proven to be in good mechanical condition and the AC output is below specifications, the charging problem is going to be a faulty rotor. If you have not done a static stator check yet and the AC output is less than as set out above it may be that the stator is defective and the static stator check will need to be done. While the regulator has nothing whatsoever to do with the alternator output, if the alternator output is good the regulator might be defective in either rectification or in limiting the output to the battery to under 15 VDC. If AC output is low and the stator has passed the static stator check then it is likely that the permanent magnets in the alternator rotor are weak. A permanent magnet can lose its magnetic strength if it is dropped or shocked such as letting it snap into place when being installed or possibly by use of an impact wrench to remove the compensator fastener etc.

May 27, 2014 | Harley Davidson FLSTF - FLSTFI Fat Boy...

1 Answer

I have combo led fuel gauge battery voltage indicator on my 2000 FLTSC. While riding I noticed the voltage was maxing out and speedo quit working. Went to do the stator voltage regulator test and notice a...

If oil gets into the connector it can be caused be 2 things usually. The first is oil left over from the oil changes that seeps into the connector and causes it to short out. The second is the stator plug leaking through the wires into the connector. The first one is usually the culprit. If the stator shorts out or takes out the regulator there is no way for the system to shunt excess voltage to ground. Therefore spiking the system and causing havoc on the system. i.e. the speedo. I'd be willing to bet you have an overcharge code . I would check that first.

Nov 01, 2013 | Motorcycles

1 Answer

93 chrysler concordburns out voltage regulator

check for a broken wire to the regulator or a short in one of the wires. Also clean the both battery terminals as the black crust build up will cause problems with the charging circuit.

Apr 05, 2013 | Vehicle Parts & Accessories

1 Answer

I am thinking of buying a 94 Fatboy, what can I expect to fail??

Most front wheel vibrations are the result of lack of maintenance. Keep the tires inflated properly to keep the tires from cupping. This bike has tapered wheel bearings, front and rear. The bearings must be lubricated at 10,000 miles and whenever new tires are installed. Don't take the bike to the car wash to wash it. You will blow the grease out of the wheel bearings with the high pressure.The bearings will then rust and pit, causing them to need replacement.
Nothing lasts forever, but most EVO voltage regulator problems start when the regulator comes partially unplugged from the stator at the engine case. When partially unplugged, the AC voltage from the stator will arc to the pins at the regulator connection, causing the pins to burn away. This can fry the regulator and cause the battery not to charge. Just regularly make sure the regulator stays plugged to the stator and you should have miles of troublefree riding.
I own a '91 bagger I bought new. I've only replaced 2 regulators on this bike, and both were because they came partially unplugged from the stator.

Nov 10, 2012 | Motorcycles

1 Answer

My 01 fatboys dim lights get bright for a sec then go back to normal. like a power surge

Look to voltage regulator Im thinkin.....check w/ vom.. if you do change id change stator too...good luck..

Jul 14, 2011 | Harley Davidson FLSTF - FLSTFI Fat Boy...

1 Answer

Charging system is overcharging the battery. Already changed the rectifier which had a burnt plug. also changed the stator. still pushing 17-18 volts to the battery. any solutions?

rectifier (voltage regulator) is responsable for stady 14V suply.
It should be him. Check battery when not conected?!
But I realy think it's rectifier cousing problem!

Apr 08, 2011 | 2001 Yamaha YZF-R1

1 Answer

My turn signals don't seem to be working, I keep having head lights blown out, and have several batteries eaten. I think it could be the stator or the voltage regulator. Ideas?

Hi Hosedragger1
I would be checking the charge voltage the alternator is generating at the battery terminals. . Lift the engine revs to 3-4000 rpm, if it exceeds 14.5 volts or so with the headlight on, then it is overcharging and will need further investigation. Replacement of the regulator module may be a good move here. There is not much else that will allow the battery to be overcharged, and it sure sounds like it is in this case from your symptoms. Happy to answer any questions you may have about it.
regards robotek

Jan 19, 2010 | 2000 Suzuki SV 650

1 Answer

The wires going to the voltage regulator keep burning up.

Common problem with poor quality parts, the regulator is the problem, the generator is working other wise you would not have fried the wiring, you answered your own question. someone telling porkies to get more money from unsuspecting client?
The regulator controls the voltage not the generator, the generator only supplys the voltage it cannot overcharge unless the regulator is not working properly, simple!

Jul 27, 2009 | 2002 Yamaha V Star 1100 Custom

1 Answer

Overcharging battery!?

If it goes over 17 then there is definitely a regulator fault, regardless of what the stator is doing. The very purpose of the regulator (it 'regulates' the voltage within limits) is to NOT allow the output dc voltage to climb when the stator output rises (normal) with increased engine rpm. In other words - by nature of way it works normally, the stator AC output Voltage will rise as the engine rpm increases - it will continue to rise all the way to peak engine rpm. The Rectifier/ regulator with its double-barrel name performs two functions: the first - rectifier - converts the AC output of the Stator to DC volts - if 'UN-regulated' the DC volts would also climb proportionally to engine rpm. But that is where the second function of the Rectifier/Regulator - the Regulator - comes in. The Regulator's job is to stop the voltage rising over a certain threshold even if the stator is trying to drive it higher. It does this by 'shunting' current to ground (short circuit effectively) in a series of pulses; this controlled operation is called regulation. The limit is going to be 15V absolute max and more typically 14.5 or so. If the output rises about this value then it absolutely is NOT regulating. Failures of the regulator where they simply don't regulate and allow full voltage to pass are rare (but not impossible) - much more likely to be short or open circuit, neither or which would give the symptom you have. It still sounds almost like you maybe wired it incorrectly? The stator is inside the left crancase cover - whether or not it has its own problems, have nothing to do with the lack of regulation causing battery volts to go to 17V.

Nov 10, 2008 | 2006 Triumph Daytona 955i

Not finding what you are looking for?
Lands Phones Logo

232 people viewed this question

Ask a Question

Usually answered in minutes!

Top Harley Davidson Lands Phones Experts


Level 3 Expert

102366 Answers

David Payne
David Payne

Level 3 Expert

14161 Answers

WTF Chuck.....
WTF Chuck.....

Level 3 Expert

386 Answers

Are you a Harley Davidson Lands Phone Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides