After recently reading about a hack to get a Quick Charge 2.0 (QC2.0) USB device to output 9V and 12V instead of the typical USB voltage of 5V, I read up more on the standard and (along with several others) noticed that Quick Charge 3.0 (QC3.0) offered support for many more voltages.

QC3.0 will supposedly supply any voltage asked for between 3.6V and 20.0V in 0.2V increments.  I have an old boom box radio that takes 10x D Cell batteries, which are now quite expensive (and also heavy!), so I thought QC3.0 would let me easily get the equivalent 15V required to be a drop-in replacement.  I ordered a QC3.0 power bank on Amazon to give it a shot.