how to modify current for 1W LED driver

Discussion in 'General Electronics Chat' started by takao21203, Oct 7, 2014.

  1. takao21203

    Thread Starter Distinguished Member

    Apr 28, 2012
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    I want to build a small heater for my ants.

    Powering 3 large resistors through a 1W LED module heats them up to a pretty high temperature (after a while).

    The PET bottle will be used to contain the PCB (i made the cut with a gas soldering iron).

    But the module turns very hot actually I am concerned about it.
    Is there an easy way to reduce the current? Maybe there is a current sensing resistor?

    By the way it is a module to use some of these LEDs in series so it puts out variable voltage 10 to 16 volts.

    Resistors are 3x 100 Ohms parallel.
     
  2. takao21203

    Thread Starter Distinguished Member

    Apr 28, 2012
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    Also how to transmit the heat isnt entirely clear yet.

    I bought some teflon pipe- maybe I could wind that around the resistors, and make a coil at the other end too, and measure temperature. Then turn on/off the resistors with a controller.

    I'd need a small pump, slow RPM. The resistors dont heat up so fast, takes a couple of minutes.
    At the other end I'd want a water temperature of maybe 26C or so.
     
  3. takao21203

    Thread Starter Distinguished Member

    Apr 28, 2012
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    maybe just tape the resistors to another PET bottle and pump the water out of it, isolate it so the resistors only heat the water.

    If I buy a heating foil, it will get far too hot, only need to raise temperature to 20C or so. It is cold now outside and I have the ants on the window sill because there are plants inside and they need light.
     
  4. ronv

    AAC Fanatic!

    Nov 12, 2008
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    You need to put the resistors in series, I think. If the module is a constant current LED driver it will want to put out at least 10 volts. So 10/33=.3 amps. .3 amps at 10 volts is 3 watts. To much for your driver. If you put them in series it will put out 16 volts (maybe a little more) so 16/300=.05 amps. .05 X16=.8 watts - ok.
    I don't know what you cage looks like, but I think you might bolt the resistors to a metal plate and place it under it. I'm not sure how to adjust the temperature. Maybe by how far away the plate is. It may be a very slow change so you will need to be careful.
     
  5. takao21203

    Thread Starter Distinguished Member

    Apr 28, 2012
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    yes i know that its important not to fry the ants. Its a plastic tub, open at the top, and I spray with water mist every day.

    Its a 1W LED driver, not 1W driver. I could measure the voltage, yes.
    But it gets too hot.

    These LEDs are rated for 300mA actually.
     
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