Tadd,
Not sure about the USB, but I'll give it try later today. I use a micro USB rated for 3 amps connected to the screw terminals for my Pi 3 to avoid low voltage alerts that I get with the USB-USB Micro cable. I know from my days working with a building automation Bacnet router that those cables are problimatic as power cables.
--
73
Dave
WB9TEN
