[DavidTrap (David)]

I don't think it's going to work with standard dew strips which are designed to work at 12V For example, a 4 inch dew strip from Dew-Not draws 0.61amp and produces 7.3 watts of heat at 12V.

According to my maths, that means it's around 20ohms of resistance.

If connected to a USB hub delivering 5V, it would draw only 0.25amp and produce only 1.25watts of heat.

Essentially, you've got a smaller voltage potential from the USB hub (5V) trying to "push" electrons through the same resistance. The current flow will be smaller and so the total energy converted to heat will be less.

To get the same "heat" delivery from 5V, you'd need a lower resistance and wind up drawing a much higher current. Theoretically, a USB hub that can deliver up to 2amps per socket could delivering up to 10watts, so if you want to use a voltage converter to raise the voltage to 12V, you could use standard strips, otherwise, you'll need to make custom dew strips to run at 5V.

I'm relying on the equations Volts = Amps x Resistance and Watts = Volts x amps from high school physics. Happy to stand corrected if I've got this wrong.

DT