How Many Pixels Can I Connect to my HolidayCoro Controller or Receiver?

How Many Pixels Can I Connect to my HolidayCoro Controller or Receiver?

We often receive the question about the specific number of pixels that can be run on any given controller or receiver.  This article explains how to determine how many pixels you can run.



First, we need to determine a few inputs:
  1. Assumptions
    1. All pixels on a given controller/receiver/power supply are the same type / wattage
    2. Calculations below are based on worst case, which includes:  Full white output (Red, Green, Blue on at full output)
  2. Wattage of Pixels
    1. To determine the wattage of pixels
      1. Actual Measurement - Turn on a given number of pixels, then measure, using a multi-meter, the current consumption of the total pixels divided by the number of pixels.
        1. Example:  50 pixels are connected to one output, the pixels are driven to 100% output with full white.  The multi-meter reads a power consumption of 3.5 amps at 12 volts.   3.5 amps times by 12 volts is 42 watts.  42 watts divided by 50 pixels is .84 watts per pixel at 100% output.
      2. Vendor Provided - Most reputable vendors will list the wattage or amperage per pixel.
    2. Notes
      1. Don't use "rules of thumb" you might find on the internet if you are close to the limit of the controller, when in doubt, measure the actual power consumption.
      2. Pixels will consume more power as they are turned on longer.  So a string of 100 pixels when first turned on might consume 40 watts, then after 20 minutes might consume 48 watts.  Determine how long you might have the pixels in a "full white" output mode that increases power draw.
      3. Many vendors have inaccurate measurements or use "generic" amounts.
      4. Don't rely on the generic amounts provided in xLights for power consumption calculations.
  3. Percentage of Output
    1. It is very common to run pixels at ratings lower than they are capable of.  Common amounts are 50% and 30% of maximum output.
    2. Notes
      1. Running pixels at lower outputs allows you to run more pixels on a given string.  
  4. Number of Pixels
    1. Determine how many pixels will be connected to any given output.
    2. Notes
      1. There are generally limits in the amount of pixels you can run in a single run without power injection - per output.  The main factor is the percentage of output and the quality of wire in the pixels.
  5. Fuse rating of the output
    1. Most controllers will have a fuse rating at 5 to 7 amps.  All pixels connected to that output must have an amperage below that fuse rating.
    2. 5 amps at 12v = 60 watts
    3. 5 amps at 5v = 25 watts
  6. The Math
    1. The math is pretty simple
      1. Assumptions
        1. 5 Amp Fuse Rating
        2. 350 Watt Power supply over 16 outputs
      2. Can I run this many pixels on this output:
        1. 120 pixels at 12v at .45 watts per pixel would be 54 watts.  So yes, this would work as it is below 60 watts of power consumption.
      3. Can I run this many pixels on this controller:
        1. 120 pixels at 12v at .45 watts per pixel on 16 outputs would be 864 watts total with all pixels on at full white.  No, this would not work as it is over the 350w input power.