It might pay for itself eventually. Suppose I'm making toast -- a process that normally uses around 1100W, anywhere in the world. At 120V, that's about 9A, wh

It might pay for itself eventually. Suppose I'm making toast -- a process that normally uses around 1100W, anywhere in the world. At 120V, that's about 9A, which is fine for a 15A branch circuit running with 14AWG wire (the very cheapest of wire that we ever use for this stuff in the States). At 48V, making toast requires about 22A, and thus needs something more like 10AWG wire, which uses about 2.5x as much copper. But that bigger wire only needs to be purchased and installed one time, while any efficiency gain gets to be kept (presumably) forever. And that efficiency gain (achieved by having fewer, simpler electronics between the sun and the toast in my kitchen) means a smaller solar array, and a smaller battery bank -- stuff that does wear out eventually. So why not do both? Why not stick with high voltage (because it's cheaper), and also switch some things over to DC? Neither the wires in my walls nor the electromechanical bits of my toaster know or care if things are being powered with 120VAC or 120VDC. The toast comes out the same either way. Why must voltage also decrease?