Voltage Gauge reading on Street Glide

Discussion in 'Touring Models' started by craig Lee, May 19, 2016.

  1. craig Lee

    craig Lee Active Member

    I have a question just for my knowledge and maybe some others. I've noticed on my '08 SG with 90,000+ miles now that the voltage meter at start up is around 14.5-14.7 volts. After riding some time on the freeway, it goes down to around 13 volts and then when I get off doing streets, it goes back up to 14.5-14.7 volts. I have a new battery using a battery tender, a new voltage regulator and pretty new stator. It's pretty much done this since day one with the OEM manual stating the gauge will read 13v-14.5v when running. Question: is the fluctuation to 13v at freeway speeds the regulator cutting back the voltage with the battery now fully charged at freeway speed/rpm and recharging at the 14.5-14.7 when on streets or.....? Thanks again for such a great site!
  2. Jack Klarich

    Jack Klarich Guest

    Yes, once the battery is fully charged the regulator will shunt the voltage it does this for 2 reasons 1 the battery does not need the voltage 2 by shunting it gets rid of heat to protect itself
    Blue Wide Glide, Fisherking and zoob2 like this.
  3. craig Lee

    craig Lee Active Member

    Bingo, that's what I was thinking/hoping Jack! I "know" there is "never" a lame question on this forum but I've always wondered and have never found the exact answer. Leave it to this forum, answered promptly and I still feel good about the question. :) HDTALKING, the best!!
    Jack Klarich likes this.
  4. Jack Klarich

    Jack Klarich Guest

    Ride safe and happy :)
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  5. Winterwind56

    Winterwind56 Member

    I recently installed a new Voltage Reg on my bike , same bike '08 FLHX with 17.5K miles. The gauge is displaying 16V...I was told two things from others that know more than I. (1) It's no big deal (2) My gauge may be faulty. Any suggestions.

    This was done about 3months ago...bike ran fine till I noticed my 'low beam' headlight will not go on....however, the Hi Beam does.
    and my odometer is reading a much higher number, like 78,222 miles, when it should read 17.5K miles. what's up w/ that?

    The battery is fully charged, keep it on a tender all the time and otherwise than these issues, the bike runs fine....everything is stock w/ the exception of my exhaust (true dual) and the new Volt. Reg.

    CHZWIZ Active Member

    You had the reg installed 3 mo back and have you been having these issues from the time you got the bike back? I personally would take it back to the shop that installed it. Obviously you weren't experiencing these things before the reg installation.
  7. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

    If you have a volt ohm meter (VOM) measure the DC voltage across the battery and compare it to your gauge.
    Does the odometer read properly with the key on and not running?
    Does the low beam work when bike isnt running?
    You may just have a bad headlamp.
  8. Winterwind56

    Winterwind56 Member

    I installed the Voltage Regulator (it's a plug and play thing) wasn't a/b to bring it into the shop for that. I was also told when you change the Voltage Reg, it's a good idea to change the stator. I didn't do that, but can..it'll just take a lil time...and $$$ ~

    No, the odometer does not read properly w/ the key on and not running. No, the low beam does not work when the bike isn't running....Is there a way (of checking the headlamp) other than plugging it in and turning on the battery ?
    Last edited by a moderator: Mar 2, 2017
  9. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

    Pull the headlight out and hook it to a battery charger. Clamp the negative leed and touch the positive leed and if it's good it will light up. If it lights up it will do so on low beam.
  10. biscuit

    biscuit Junior Member

    You need to check your charging/ output voltage with a Multimeter-as already mentioned by Bowden.(You need to use a "proper" voltmeter and one that will give you an exact reading.I really dont know if the bike voltmeter would be entirely accurate)
    With the engine running of course.
    Check the voltage across the battery terminals at idle and maybe at 2000 to 2500 rpm.
    If you have somewhat more than 14.7 voltsD.C it would indicate you have a problem.
    It may very well be your gauge is correct and you have burnt out the low beam filament of your headlight due to higher voltages than normal going thru it.Take out the lamp and have a look at it.You'll soon see if the low beam filament is gone.Of course, if you do get an actual 16VDC going through electrical system, it is entirely possible you may have caused some damage to other electrical components.
    I think you also need to check the connections you made installing the " new" VR and make sure they're correct and tight.
    There's information elsewhere on this site on how to check your stator as well.
    Electrically, it is considered normal practice to replace both the VR and the Stator when one or the other fails as each has an impact on the other.