Why Not Use Low Voltage Direct Current?

disassembled LED lamp

Disassembled LED lamp
“EcoEnergy EE-02-010” by Dmitry G. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons

I recently was at Lowe’s and finally bought one of the outlets I had been eyeing for a while with USB charging ports built in. This brought back a thought that I’ve had before that relates to both baby-proofing and efficient use of distributed, Photo-Voltaic (PV) generated electricity. I’ve gathered through the years that high voltage alternating current is so widely used because it’s great for long distance transmission. But is that still the most important factor to optimize? What devices in a modern house actually use alternating current and high voltage? The computer in my pocket (smartphone) charges with 5V, and my Novena desktop will be plugged in to 12V (see the top left corner page 5 of the motherboard schematics–I’ll have to study these further to see why not 5V). I figured that Compact Flourescant Lights (CFLs) would be one of the few devices to actually use alternating current. Turns our they do, but not what they get over the wire. According to the CFL article on Wikipedia, they rectify the 60Hz incoming and bring their own transistors and inverter to get the high frequency signal they need. I’ll have to further explore what kind of voltage they actually use. My first introduction to powering LEDs was with coin cell batteries, when I learned about throwies at the Last HOPE. Presumably the LED lamps you twist into an Edison screw (just learned that that’s its name) bring their own rectifier and could be powered off of significantly fewer volts. Having mentioned the Edison screw, a transition to wiring the house with low voltage direct current is probably the perfect opportunity to also ditch the Edison screw for something that is significantly less likely to electrocute me, and more importantly, my children.

That covers computers and lights–things we want everywhere in our house. Vacuum cleaners are also nice to have everywhere, but my mother in law has a robot with a battery sweep her floors. I like to think that’s the way of the future. So that leaves hair dryers, refrigerators, microwaves, clothes dryers and other generally large but fixed location devices. I would hope that semiconductors could somehow help them become much lower voltage just like LED lamps did for lighting, but I don’t know if that’s realistic. But say you were to keep the current high voltage for charging stations in the garage and appliance hookups in the kitchen, laundry room, and maybe bathrooms. Bedrooms, living rooms, and offices could potentially be wired with safer, and potentially more PV-friendly, low voltage direct current. While we’re at it, maybe bundle it with data, like power over ethernet (that topic might be worth its own blog post). I really don’t know what I’m talking about here though, so before I go on longer, I’ll have to learn how to simulate electrical transmission and make some comparisons. If anyone knows of libre software useful for that, let me know. I may start by firing up QUCS once again.