Charging system failure low voltage

Arnie Burke

• 7339 Answers
• Posted on Aug 19, 2009

SOURCE: Voltage Regulator Problem?

u want to chec alternator as well-ther r test u can do so buy a clymer manual which r very detailed-iv seen hd books in library sec 629

SOURCE: Voltage problem when running bike

The voltage regulator should present 13.5 to 14.5 volts at the battery to charge it properly (engine at fast idle). I'm not sure if the V regulator is adjustable or not. If not, then it probably needs to be replaced. The alternator appears to be trying to do it's job, although it may have an open diode or winding if the alternator is 3-phase. An oscilloscope is the best tool to check for all three phases working properly. Good luck!

SOURCE: After leaving the last gas

Ok, let's check the charging system. The battery is easy. Take the battery out of the bike and take it to an automotive parts store. Ask them to load test the battery for you. If the battery is over two years old, it could need replacing.

Once you're sure the battery is good and it is FULLY CHARGED, we can test the rest of the system. You'll need a DVOM (digital volt ohm meter) to check the system. With the battery back in the bike, connect the DVOM across the battery. Red meter lead to the positive terminal of the battery, black meter lead to the negative. Put the meter's function selector switch in DC VOLTS, 20 VOLTS or greater. Start the bike and bring it to a high idle. The meter should read 14.5 - 15.0 volts.

Now, to test the stator, follow the wires from your regulator down to where it goes into the engine cases. Disconnect the connector and look into the engine side of it. You'll see two metal contacts down in there. Set you meter's function selector to AC VOLTS, 50 VOLTS or greater. Start the engine and bring it to a high idle. Touch each one of the metal contacts down in the engine side of the connector with a meter probe. It makes not difference since we're measuring AC voltage at this point. The meter should read at least 30 volts.

Now, if the alternator (stator test) does not put out at least thirty volts, the stator is bad and needs to be replaced. If the alternator does check good but not enough voltage at the battery, your regulator may be the culprit. Make sure all connections are clean and tight and that the body of the regulator is grounded good. Recheck the test at the battery. If it still fails, replace the regulator.

Now, I've seen may problems such as your's that are intermittant. In other words, the problem is here on minute and gone the next. I fought that on one bike for over a year until we finally replaced the entire charging system and fixed it. If your bike proves to be doing that, you may wish to consider that option. Fix the thing and be done with it. I wouldn't buy the rotor, just the stator and the regulator.

Good Luck
Steve

Testimonial: "right on with the test procedure. Battery didn't show it was charging. While the stator test showed 30vac, an ohm test showed it was grounded. Thanks "

SOURCE: 2005FLHTCI The charging system keeps

I had the same problem with mine, then the volt gage droped to 0...
It had a bad stator