Hello, I have 20 led lights using 2 AAA 1.5 volts batteries each

Discussion in 'General Electronics Chat' started by Jesus Portillo, Apr 23, 2016.

  1. Jesus Portillo

    Thread Starter New Member

    Apr 23, 2016
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    I want to see if they can be connected all 20 in series, if they can, do I need a 60 volt power supply?, and what size of resistor I need and if please can some one show me how to connect them. I know that I am going to buy special tiny wire. These lights at the present are all around my pergola in my garden. every time we go outside I have to turn the switch on 20 times and off 20 times. Please I'll appreciate if some one give me an idea in how to connect them all and place One switch near my door. I thank in advance the person that can help me with this project. Jesse
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    Welcome to AAC!

    With 2 AAA batteries, you'll need to operate them in parallel; each, ideally, with it's own current limiting resistor. To determine an appropriate resistance, we need to know the LED forward voltage.
     
  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Put them all in parallel with a 100 ohm resistor in each led....
     
  4. dl324

    Distinguished Member

    Mar 30, 2015
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    I'm thinking the LEDs are going to be white and a 3V source would be marginal...
     
  5. takao21203

    Distinguished Member

    Apr 28, 2012
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    ive done this with 1 transistor, 1 10mh dogbone inductor, and one pushbutton.

    You can see as header logo on my ebay. The efficiency isnt so great but at the low current its not so bad either.
    Yes you need 60v or even more.

    The circuit uses 2n3906 the LEDs are connected parallel to the main coil winding, which is connected to base on one end.
    the other is open connect with pushbutton to start.
    The "primary" is 8 added turns. Its a freaky circuit and probably not easy to build since the layout is sensible.
    But effective and simple.

    The 12t to 35v converter can be hacked just need better MOSFET and capacitor and change the pot..
    I wouldnt recommend it since it can output dangerously high currents at 80v or so.
    Used it to drive 2x 20W white power LEDs in series some time ago.
     
  6. dl324

    Distinguished Member

    Mar 30, 2015
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    That's where I thought we might end up. I remembered reading your post regarding a joule thief driving 20 blue LEDs.

    Eliminates the current limiting resistors and simplifies wiring.
     
    Last edited: Apr 23, 2016
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Or you can use a garden solar lights chip, or joule thief.
     
  8. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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