Initially we were working on data from our supplier that each of the LEDs in the pixel strings used about 18 mA of power on average. In our default 2 x 8 stick layout, this would mean since we have 16 pixels, that would mean an average consumption of 288mA per Accessible Pixel Stick. However, these estimates aren’t quite right for maximum power consumption.
18mA per LED: 16 x 18mA = 288mA per Accessible Pixel Stick Approximate power dissipation ( 5v x 0.66A ): 1.44 watts
After testing both an NeoPixel clone from the UK mixed with a generic WS2812-8 from China, the maximum current draw that we have measured is approximately 660mA. This is with every pixel set to maximum (255 on each colour) so it’s a very bright almost white.
Working backwards this means that the maximum current draw would be 660mA
660mA / 16 = 41.25mA per LED Approximate power dissipation ( 5v x 0.66A ): 3.3 watts
Knowing what we know about LEDs, however, each LED would theoretically draw a maximum of about 20mA, so each pixel at full intensity would run at 60mA giving us a total per Accessible Pixel Stick of 960mA
20mA per LED: 16 x 60mA = 960mA per Accessible Pixel Stick Approximate Power dissipation ( 5v x 0.96A ): 4.8 watts
Of course, we won’t be running these LEDs at maximum, for both thermal and for the life of the LED strips. We’d probably recommend running them at 60% of maximum as the highest setting.
960mA * 60 / 100 = 576mA per Accessible Pixel Stick Approximate Power dissipation ( 5v x 0.576A ): 2.88 watts
2.88 watts over 16 LEDs sounds like a good upper limit for the LEDs to us.