I’m currently looking into various DC DC converters and was confused that the Meanwell DDR-60 series only shows a typical rating but says nothing about the efficiency at idle. From AC/DC converters I’m used to have a curve that starts at idle and maybe 70% and goes to 100% load, having the peak at ninetee something.
(Edit: link goes directly to the PDF)
Even on the equipment where you do get a graph of efficiency vs load, the line usually only starts at 10% load - that’s where your 70% efficiency figure is for.
As noted, at 0% load efficiency is by definition 0%.