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Thread: Volt Meter Reading

  1. #1
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    Volt Meter Reading

    Started to go for a ride today noticed my volt meter was only reading 12 volts at 3000 rpm,I have never put much faith in it, because most of the time it reads 12 to 13 volts,but today it would not go past 12 volt,my hand held tester,reads 13.08 at 3000 rpm,

  2. #2
    Sir Darby Darryl Cainey's Avatar
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    Never had much faith in small in dash voltmeters.

    Put a good meter across battery terminals for best results!
    Ambassador BMW MOA Ontario Canada
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    1977 R100RS, (Retired) 1993 R100GS (just getting started)

  3. #3
    Administrator 20774's Avatar
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    Also check out my "fun" with the fairing voltmeter here:

    http://www.bmwmoa.org/forum/showthre...Fairing-Gauges
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  4. #4
    Bluenoser
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    Quote Originally Posted by galaxie View Post
    Started to go for a ride today noticed my volt meter was only reading 12 volts at 3000 rpm,I have never put much faith in it, because most of the time it reads 12 to 13 volts,but today it would not go past 12 volt,my hand held tester,reads 13.08 at 3000 rpm,
    Your reading with either should be more like 14 volts, so something is not right. 13.08 is too low and something is going on with the charging system.
    1971 R50/5 SWB with R75/6 drivetrain
    2013 DL650

  5. #5
    Registered User Bob_M's Avatar
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    On my 82 R100RS I have found that over time the readings on my dash mounted voltmeter grow increasingly weak. As a gentleman of a certain age, I know about entropy. To counter that inevitable process of wearing down, every 4 or 5 years I disconnect the battery, then go remove, reconnect and when loose, tighten ever spade connector. Some, like the connectors up, inside the dash are hard to get to. Others like the turn signals or diode board require a little disassembly. I get inside the headlight to verify good connections in there, and spin the fuses in their holders to knock loose any film of oxidation. I also make sure the grounds insde the alternator cover and the battery ground are clean and solid. After I am done the volt meter reads 13.9 at 4000 RPM. It is entirely possible that the weak readings on the voltmeter are the result of several weak connections or poor grounds throughout the bike and not the bad performance of the gauge.

  6. #6
    Benchwrenching PGlaves's Avatar
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    It is my personal opinion that the best use of the dash mounted voltmeter is to paste a picture of your spouse, significant other, child, grandchild, or other significant image to glance at from time to time while riding.

    I have heard more troubleshooting nightmare stories by people chasing an indication from these OEM voltmeters than almost any other Airhead problem. Get a good VOM and check the system per Rick Jones book.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  7. #7
    Registered User toooldtocare's Avatar
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    I used mine to remind me to turn off the turn signals. It would swing back and forth from 8 to 13 volts like some one was waving their arms. Caught my attention much better than that green light.

  8. #8
    R100GS, '89 Guenther's Avatar
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    Some numbers while not watching THE number

    I wouldn't give a damn to the number on a dashboard mounted voltmeter. But...I would keep in mind what the number is/was when the electrical system worked at >3,000 RPM . If one day the reading is off by more that 0.5V I would look for a problem.

    My R1000GS shows 13.5 to 13.6 at the battery starting at about 2,700 RPM. My stock batteries have a life cycle of about 5-6 years whith mostly highway miles. YMMV!

    I added the life cycle of my batteries as an indication that the charging voltage and my typical driving pattern seems to be just right to keep the battery a-live.

    /Guenther
    Last edited by Guenther; 05-31-2013 at 09:38 PM.

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