High Voltage output

Discussion in 'Electrical' started by MarkH, Sep 9, 2013.

  1. MarkH

    MarkH New Member

    1993 FLHTC,
    constantly loosing voltage regulators, and burns up batteries.
    Regulator replaced 3 times in 2 years.
    test: 13.2vdc at battery during low idle - 350rpm
    14.8 vdc at battery during high idle - 900rpm

    performed diode test of regulator: pass

    stator replaced 4 years ago

    any clue as to why, the regulators keep going out and causing high voltage?
  2. marcus22

    marcus22 Junior Member

    Im sure Hoople will be on to help you out, but in the mean time to answer the question of why so many voltage regulators? Maybe its too much voltage drop in your system. Maybe this will help:

    Hoople told me to test the voltage output from the regulator and compare it with the battery voltage while the bike is running. theoretically the should be the same, but they are not. I associate it like water in a pipe "friction loss". you have loss in voltage in your system through the wires and connections just like water psi in a pipe. This is called voltage drop. Your voltage regulator is putting out voltage (im gonna say 14 just for an example) and if your battery is reading 13.5 thats a .5 volt drop.

    Hoople explained it to me like this:

    "So if you measure a voltage drop of just .50 volts, that really represents 25% of the stator's total output being wasted. That means the stator & regulator needs to work overtime just to keep up with the loses of poor connections.. The regulator and stator will now be on overtime and will run hotter than they should. If your lucky, a diode will open when the regulator finally gives up. But if it shorts, the stator is 30 minutes from its death."

    to test the voltage drop, puncture the sheathing on the two output wires on the voltage regulator with your multimeter pins and read what the voltage output is while the bike is running. Then compare that reading to the batteries voltage with the bike running and at the same RPM.

    hope this helps.
  3. Hoople

    Hoople Account Removed

    Marcus, You make it all worthwhile!:s
  4. marcus22

    marcus22 Junior Member

    well I'm glad and, Im sure others are also glad your here to help us non-electric folks out.
  5. marcus22

    marcus22 Junior Member


    looking back at your post above. i don't believe that voltage is high. the system should produce more than 12 vdc at the battery. my bike will run in the 14 range.
  6. scootin

    scootin Member

    14 volts is about right for that bike.
  7. Jack Klarich

    Jack Klarich Expert Member

    Keep in mind a fully charged battery makes all the difference when checking your system:s