Voltage drop

Discussion in 'General Electronics Chat' started by Ady, Feb 14, 2009.

  1. Ady

    Thread Starter New Member

    Feb 14, 2009
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    0
    Hi everyone, my name is ady and I have a voltage drop question for you.

    I own a Trike which I have just fitted a volt meter to so that I can monitor the condition of the battery and check whether the alternater is charging it properly.
    While the trike is idling (say at traffic lights) the volt meter reads charging at about 14 volts, however when I set off the volt meter drops down to under 11 volts and will stay there until I pull up again and put it in neutral, where it will show 14 volts again. (please see attach picture)

    Can anybody shed light as to why there is a voltage drop when the trike is in gear and moving.
    Thank you in anticipation
    Ady
     
  2. n9352527

    AAC Fanatic!

    Oct 14, 2005
    1,198
    4
    At which points do you connect the voltmeter? It has to be connected to the battery terminals. The drop might be because it is connected to the wires that carry current to the motor, thus the voltage drops across the wires when the motor is drawing a lot of current.
     
  3. Ady

    Thread Starter New Member

    Feb 14, 2009
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    0
    Hi there and thanks for getting back to me.
    The volt meter is connected to the terminals of the battery and on the spade connectors at the back of the voltmeter. It doesn't matter which way round they are connected, the result is the same.
    All the readings are right according to the manual, except it doesn't mention that there should be a drop to below 11 volts.
    The only things taking power are the engine a little, 2 led marker lights, 2 strip leds (very minimal) and a tail light. If it was anything to do with these I would have thought the reading on the volt meter would have been at 11 volts all the time, but it only goes to that when the engine is running in gear. The minute it is in neutral and idling the voltage needle goes up to around 14 volts, only to drop again when I set off.
     
    Last edited: Feb 14, 2009
  4. Ady

    Thread Starter New Member

    Feb 14, 2009
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    0
    Just another thing to point out.........................I have been told to connect a multimeter accross the battery terminals and check for an AC reading..............there should be none or very little showing. It actually read 24.3 AC at idle and 27.7 AC at 2000 revs. Could this be the regulator that has packed up maybe??
     
  5. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    I thought it was a battery-powered vehicle.
    Does the multimeter read any AC when everithing is completely off? Or try measuring another 12v battery. If it says anything else than zero, then it means you have a cheap multimeter which doesnt measure AC accurately, and you cannot use it to measure AC superposed on DC.
     
  6. Ady

    Thread Starter New Member

    Feb 14, 2009
    4
    0
    Hi there guys, just got in from the garage after replacing the regulator with one that I borrowed from a friend, and it looks like it is my regulator that has gone. The one I borrowed read virtually nothing, but when I put the original one back on, it was back to 24.3 AC. I think this problem is now resolved and I would just like to thank you guys for your replies. I will keep this site in favourites as I'm sure there will be other days of electrical gloom.
    Cheers Lads:)
     
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