DC Wiring for the Home

October 20, 2011 | 4 Comments

The Brits are first with a DC (Direct Current) system for the home.  It’s time and welcome.  It should become an international standard as soon as possible.

The energy losses from converting alternating current (AC) of the grid to DC can be up to 45 percent. Most small electronic devices run on, or with converted DC converted by those power blocks and unseen internal power supplies.  Most of the heat lost from that computer is from the conversion of the grid AC to the DC the computer needs.

The list is long, televisions, computers and laptops, the phones, the cell phone charger, and all those power blocks all deliver DC.  Plus add in the compact fluorescents and the coming LED lights.  It would be far simpler, cheaper and sensible if the home had a DC circuit set installed.

Better still would be if there was an international standard so all those power blocks wouldn’t be needed to buy and dispose of when the device or appliance quits or becomes obsolete.

Last week, Moixa Technology of the UK unveiled its Smart DC network, which uses solar panels and off-peak grid electricity stored in batteries to power electronic devices in the home such as televisions, laptops, mobile phones and LED lighting and converts the DC generated by the solar panels into AC to sell back on the grid.  Step one has arrived at last.

The Moixa network is made up with solar panels, DC sockets, an electric vehicle-quality Li-Fe battery that could power LED lights in a typical house during a power cut for a day, and a “hub” device that takes information from a smart meter.

Moixa DC Plugs in Model BMS 250250. Please visit the Moixa Webiste linked above for more info.

The hub manages the flow of electricity according to how much energy it predicts the house will need, how much is available from the solar panels and battery and how much grid power costs according to whether it is a peak or off-peak period.  Moixa has designed the network with solar power in mind.  But even without the solar panels the network has strong appeal.

A substantial backup battery and a DC wired home could get along for days in a power outage and quality engineering could extend the life of the home’s electronics should a whole house converting power supply be installed.  Even more appealing is a single power supply is going to be cheaper and should offer very high efficiency.

Simon Daniel, chief executive officer of Moixa, told the UK’s magazine The Engineer,“People just want cheap and efficient energy. Too much information is annoying but people will take good advice if it is specific to their situation.”

Here’s some attractive numbers on applying DC, users could save between 10 and 30 percent on their electricity bills, suggests Daniel.  Then an additional 15 to 20 percent can be saved on the gas bills by adding an electronic boiler monitor that predicts gas usage and turns off the heating when it’s not needed.

Moixa plans to follow a business model similar to that of Sky of the UK, making the technology easy to install by local contractors and offering gradual upgrades than can be added easily.

Moixa also plans to make the system available for between £1,000 and £3,000 per home. Daniel estimated this cost could be recouped in three to five years through savings on energy bills.   Lucky folks in the UK.  YO!  Mr. Daniel!  We here across the pond get the idea too!

Those upgrades to the network will use data on the changing price of solar panels and LED lighting decreases to tell the homeowner when it becomes cost-effective for them to install more of these products.  You don’t have to buy what isn’t practical or until you’re ready for it.

The firm expects the system to be of particular interest to those who work from home and operate electronic devices throughout peak hours, as well as to hotels and student accommodation.  The potential of this idea is much further reaching than anyone is thinking just yet.

There are many good reasons why DC should be the current of choice in the last 50 meters of the electric supply system.  Much of what is used today is already DC and more is coming.  Having a power supply converter for every single one is a huge economic cost that makes little sense.  Many devices have more expensive power converters than the device itself.

Lets encourage Moixa.  Its an idea that is overdue, needed and offers great benefits.


4 Comments so far

  1. Kevin on October 20, 2011 3:05 PM

    Low voltage DC might might sense for low power devices, but not for high power devices like large screen TVs, multichannel receivers, or performance workstations. At 12 volts, a 200 watt load can lose over 25% to resistive losses in the wiring of a typical 20 amp circuit. You’d need to make sure all your low voltage wiring runs are either very short or use huge (200 amp) circuits (very costly, might takes decades to pay for itself).

  2. Jagdish on October 21, 2011 12:47 AM

    AC power came into being due to electro-magnetic generation, which produces AC unless converted to DC at source. Photo- voltaic generation creates DC. DC is also required for electronic uses.
    It stands to reason that domestic/office uses involving a lot of 12V DC would be best served by DC. AC might be best for industrial uses where rotational power is required.
    Photo-voltaic electricity or DC/AC mains Chargers could charge batteries powering 12V DC system in the house. Inverters could be used to power equipment working on AC.
    Electric heating appliances start with a 30% efficiency of conversion of thermal/nuclear generating systems and should be discouraged.

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  4. Paul Héroux on April 15, 2014 9:36 AM

    I have written a 6-page article on why we should convert all of the electrical grid and systems to DC.
    It can be found at http://www.invitroplus.mcgill.ca/AC to DC transition.pdf

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