Will 2 AA turn a motor faster then 2 AAA?

Discussion in 'General Electronics Chat' started by stanman11, Nov 6, 2012.

  1. stanman11

    Thread Starter Member

    Nov 23, 2010
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    I got an rc car at a garage sale for a buck. its a wired remote with 2AAA but it doesnt really want to move much so I was thinking upping to a bigger batteries.
    will this work?
     
  2. Georacer

    Moderator

    Nov 25, 2009
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    1,266
    I think it's more likely that you 'll burn its circuitry, if it's digital.

    Try to clean its axis from the hair wounded behind the wheel and turn the motor axis with your hand to see if it moves freely without friction. Resistance would be a sign of dirt.
     
  3. nerdegutta

    Moderator

    Dec 15, 2009
    2,515
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    If you change from 2 AAA to 2 AA, the voltage will stay the same, but it will last longer.

    Compare this AAA datasheet to this AA datasheet.

    Please correct me if I'm wrong...:)
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    There should only be a slight, if any, difference initially - the big difference will be the run time due to the difference in mAh ratings. I suggest that out try doing some.checking with an odometer first though.
     
  5. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Check the linkage in the gears. Most likely is is gummed up with all sorts of dirt and debris.

    Or it could simply be a bad motor.
     
  6. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
    150
    Not if their total voltage is the same and their internal resistance is the same.
     
  7. Audioguru

    New Member

    Dec 20, 2007
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    Cheap little RC airplanes use tiny brushed motors (made to open and close a CD tray). The brushes and commutators wear out after a few hours of running which reduces the power and sometimes they will not start unless the motor shaft is turned a little.
    I have about 8 worn out motors.

    My more expensive little RC airplanes use brushless motors that keep running and running and running and running and running at full power forever.
     
  8. tshuck

    Well-Known Member

    Oct 18, 2012
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    The only way you should see a difference, aside from longer life, would be at startup, assuming the 2 AAA batteries could not supply the proper current for the motor stall.
     
  9. tshuck

    Well-Known Member

    Oct 18, 2012
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    ...to answer your question, unless the design was horrid and they didn't spec the motors properly, you should see no difference in motor speed after startup.
     
  10. stanman11

    Thread Starter Member

    Nov 23, 2010
    230
    4
    Ok, well that answeres my questions.
    It doesnt have any circuitry, the Controller is a spring loaded joystick and the wires gor straight to the motor from there.
    and its clean from hair its just a POS

    Thinking about putting a 3.6v Cell battery under the car body with a charging inlet and making it in to a stomper. just turn on and let it go by itself?
     
  11. stanman11

    Thread Starter Member

    Nov 23, 2010
    230
    4
    Ok guys I got a switch and a charging unit mounted in this little car.
    The car takes 2 AA 1.5 normaly. I put in it a 3.7v Lion battery but the thing is way to strong and I can smell electrical burning.
    When I connect a 100ohm resistor it wont turn the motor
    any suggestions?
     
  12. Audioguru

    New Member

    Dec 20, 2007
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    Why do you think adding 100 ohms in series with the motor will slow it a little?
    The value of the resistor depends on the operating current of the motor. Maybe you need only 10 ohms (or less) to reduce the current so it is the same as if the motor is powered from 3.0V.
    But you burnt something so maybe now the motor is ruined.
     
  13. stanman11

    Thread Starter Member

    Nov 23, 2010
    230
    4
    motor is still good. thing is way to fast. I dont get how an extra 0.6v made it so fast when 3v barely made it move
     
  14. Audioguru

    New Member

    Dec 20, 2007
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    A "3.7V" Lithium rechargeable cell is 4.2V when fully charged and it can supply LOTS of current without its voltage dropping.
    Little AAA alkaline cells do not produce much current, if loaded then their voltage drops.
    AA alkaline cells can supply twice as much current as AAA cells but not nearly as much as a rechargeable Lithium battery cell.

    You cannot do much without knowing how much current the motor is drawing.
     
  15. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
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    You could use a diode to drop the 3.6v to roughly 3.0v.

    A 3 amp diode would be advisiable, I think 1N5803 or 1N5804 is the common part number?
     
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