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Battery voltage

in General Tech Discussion 9 years ago
Just came down after a 1.2 hour flight and while in the air I got a caution that my voltage reading was 4.6 and amps of .8 on my 912ULS. When I landed, the voltage dropped back within range to around 3.5 while taxiing back to the hangar. Any ideas what would be causing the high voltage and where I might look for a solution. I usually taxi at around 2200 rpm and fly at 52-5300 rpm. Thx. for any advice you might be able to offer. The battery is approx. 5 years old and readily starts the plane every time with no issues.

  • Re: Battery voltage

    by » 9 years ago

    Please check your numbers. I suspect you mean 14.6 and 13.5 volts, not 4.6 and 3.5.

    The regulator is simply a switch that turns the charging system on and off. Switching is controlled by the regulator "C" pin, referenced to the regulator case (ground.). If the voltage at the C pin is above 3 volts the regulator will switch on, when the voltage to this pin exceeds 14 volts, it turns off. Now look at the big picture, with a properly functioning regulator, a resistive connection anywhere in the C pin circuit (power or ground side) will cause a voltage drop. The amount of that voltage drop will be added to the 14V shut off point, raising the charging voltage...unless the voltage drop is so great that the C pin drops below 3 volts
      
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  • Re: Battery voltage

    by » 9 years ago

    Sorry I meant 14.6 and 13.5 volts. Thx. for your reply but as I am electrically challenged, none of what you said makes any sense to me. Can you put it in more simple language for me if possible? Many thx. again. Help is truly appreciated.
      
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  • Re: Battery voltage

    by » 9 years ago

    Sounds normal to me. The charging system does not do much at lower RPM,s. Try power management at lower RPM,s, only turn on what is absolutely needed electrically. I even start shutting down electronics 5 miles out so that I leave the battery charged as much as possible for the next time. I learned this the hard way and burned up some of the electrical connectors in the charge system. The charge system gets overloaded if it has to charge a low battery and try to run everything after takeoff.
      
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  • Re: Battery voltage

    by » 9 years ago

    Thx. Garrett for your advice. My concern is that I am getting a warning message that my voltage is in the yellow and reading high but not in the red as of yet. Just trying to figure out what may be causing this to start all of a sudden and what I should be doing to correct it if in fact something needs to be fixed. Is my battery pooched or the regulator need replacing? I don't know but as I said I am electrically challenged when it comes to this kind of stuff but I don't want to just start changing things out without finding the cause. Thx.
    Terry
      
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  • Re: Battery voltage

    by » 9 years ago

    I would suspect the regulator last they either work or don't work. Check the connections and battery condition. Replacing the original motorcycle lead acid battery with an Odessy PC625 AGM brand helped a lot in my case.
      
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