Just did some testing on the amount of current drawn from the LEDs. In my project I'm running the APA102's at 3.3V which is technically out of spec according to their datasheet, but they seem to still work fine.

I did my testing with a set of 8 LEDs (1 blade), and I saw that:

• Each LED draws about 20mA at full brightness (white)
• At half brightness (white) each LED draws about 10mA, so the current draw seems to be linearly related to the brightness value
• With all the LEDs turned off there's still about a 7mA current draw, which means each LED consumes about a 1mA statically