Low amp draw from WS2812 strip

Using Arduino LEDs and Multiplexing
1

I can't figure out why my LED strip isn't drawing more current.

I'm driving a strip of WS2812 LEDs (5m @96/m, 480 LEDs) with a Teensy 3.1. With a short data wire, the 3.3V output drives the LEDs just fine.
I've also tested this with a TeensyLCs 5V output on pin 17 with the same results.
The LEDs are powered by a 30A 5V DC-DC converter from 12V and fed by 2 10 gauge wires that run parallel to the strip and feed power at each end and every meter along the way. The lowest voltage at any LED is at the far end @ 4.6V.

At full power the strip only draws 16A @ 5V (16A/480LEDs = 33mA ea).
it should be drawing at least 21 (45mA each based on some testing) and based on the WS2812 spec (60mA max per LED; 28A)

In my setup, I have

FastLED.setCorrection(0xFFFFFF);

When I select the white and brightness I set.
FastLED.setTemperature(0xFFFFFF);
FastLED.setBrightness(255);
Set all LEDs to white
fill_solid(leds, 480, 0xFFFFFF)
then of course...
FastLED.show();

I'm not using any of the power limiting functions of FastLED.
Why are these LEDs only drawing 33mA each instead of the 50-55mA I've read about?
Is there some odd setting that FastLED has that is pulling back brightness/

Thanks.

2

How are you measuring this current? Most DVMs will not give accurate reading on pulsed currents. Although it is full power their is still PWM going on in the LEDs, it is just that it is 255:1. The way to measure the peak current is with a very small shunt resistor and an oscilloscope, or better still a current probe.

3

You could be measuring it wrong, or..
If I understand the WS2812 datasheet correctly, typical LED current is 3 * 18.5mA.
But it could be as low as 3 * 10mA.
Leo..