Highest draw default pattern?

I am keen to have a method to reliably match the max brightness to any given PSU/strip combo.

Is there a default pattern, or a simple one I could write up that will effectively draw as much, or more power than any other pattern? I imagine it’s something like ‘all on colour X’ but haven’t been able to figure out specifics.

Update: I have just read some content that suggests white is the highest draw given it has all sub-leds on - but does that only apply to RGB Leds trying to do white? What about dedicated RGBW or RGBWW strips?

As always, advice appreciated.

White is right for rgb. For RGBW you should be able to turn all 4 leds on at the same time, no?

It seems weird, but under normal circumstances RGBW LEDs don’t let you turn on all 4 elements at once. The Pixelblaze takes the RGB values in your pattern and converts them to a carefully balanced RGBW mix. So it draws maximum power roughly when any two elements are set to full brightness.

Once you add the 3rd channel, the white LED starts to kick in, and the other color channels dim proportionally to balance the added white.

I’ve attached a short Processing (Java) function that calculates power usage based on the way FastLED (and likely almost everybody else) converts RGB colors for use with RGBW LEDs. Using this program with a pessimistic 20mw per element maximum:

  • rgb(1,0,1) uses 40mw,
  • rgb(1,0.1,1) uses 37 mw
  • rgb(1,0.5,1) uses 30 mw
  • and rgb(1,1,1) which is only using the white element, uses only 20 mw

If you want to search the forum, there’s software knocking around that lets you control all 4 channels independently, but I don’t recommend doing that unless you have (1) a need to be super, super bright, and (2) a big power supply. The maximum draw for all 4 channels set to max would be 80mw per LED.

float perElementDraw = 0.020;  
float idleDraw = 0.001;

public float evaluate(float r, float g, float b) { 
  float w,briMax,briMin;

  // whiteness is inversely related to the range between min and max, so...     
  // find brightest component
  briMax = max(r, max(g, b));

  // early out if LED is off
  if (briMax == 0) return .001;

  // find dimmest component
  briMin = min(r,min(g, b));

  // calculate and normalize the range 
  w = 1-((briMax - briMin) / briMax);
  w = w * briMax;

  // calculate and return overall power consumption
  return perElementDraw *((r+g+b) -(2 *w));
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