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Given that nearly everything in a home uses AC-DC converters, I'm also really surprised that there isn't (that I know) a standard for a whole house DC jack that

by Osiris 13y ago

Given that nearly everything in a home uses AC-DC converters, I'm also really surprised that there isn't (that I know) a standard for a whole house DC jack that can supply common DC voltages, removing the necessity for all devices to have their own AC-DC transformers.

ars 13y ago
The wires would be too big. You just can't send enough power at a low voltage. You'd need either lots of dedicated wires to each outlet, or a wire as big as a hose. AC is nice because it's easy to convert to other voltages. With DC you'd need either the exact voltage - or a converter, and if you have a converter you might as well just go directly from AC.
- Amadou 13y ago
  Seems like Power over Ethernet would be a pretty good standard to go with. Right now it's good for 25.5 watts at 44 volts. Wikipedia says some vendors have tweaked the standard to use more lines and get it up to 51 watts. To over-simplify, the higher the voltage the less loss there is on the wire for a given amount of energy (amps). Added bonus you get ethernet too so any devices like LED lights, cameras, etc can be programmable without wifi/zigbee/etc.
  - ars 13y ago
    Power over Ethernet only helps for not having to run a second pair of wires. You would still need a DC/DC converter, and if you do that you might as well just go from AC. PoE is helpful certainly, but not as a way of having universal DC in the house.
    - Amadou 13y ago
      You would still need a DC/DC converter, and if you do that you might as well just go from AC. You are thinking wall-wart type applications. I'm more along the lines of infrastructure, lights and other permanently installed devices that can be designed from the ground-up to operate at 44v.
      - ars 13y ago
        > designed from the ground-up to operate at 44v. Why? What's the benefit over 110v?
tracker1 13y ago
Maybe not, but you could certainly replace recessed canisters, or other fixtures with those that have AC/DC power supplies built in, in such a way that they can have a larger surface in the ceiling/walls or even in the fixture that can then not be part of the "bulb", and subject to the same size constraints.

by Osiris 13y ago

ars 13y ago

The wires would be too big. You just can't send enough power at a low voltage. You'd need either lots of dedicated wires to each outlet, or a wire as big as a hose. AC is nice because it's easy to convert to other voltages. With DC you'd need either the exact voltage - or a converter, and if you have a converter you might as well just go directly from AC.

Amadou 13y ago
Seems like Power over Ethernet would be a pretty good standard to go with. Right now it's good for 25.5 watts at 44 volts. Wikipedia says some vendors have tweaked the standard to use more lines and get it up to 51 watts. To over-simplify, the higher the voltage the less loss there is on the wire for a given amount of energy (amps). Added bonus you get ethernet too so any devices like LED lights, cameras, etc can be programmable without wifi/zigbee/etc.
- ars 13y ago
  Power over Ethernet only helps for not having to run a second pair of wires. You would still need a DC/DC converter, and if you do that you might as well just go from AC. PoE is helpful certainly, but not as a way of having universal DC in the house.
  - Amadou 13y ago
    You would still need a DC/DC converter, and if you do that you might as well just go from AC. You are thinking wall-wart type applications. I'm more along the lines of infrastructure, lights and other permanently installed devices that can be designed from the ground-up to operate at 44v.
    - ars 13y ago
      > designed from the ground-up to operate at 44v. Why? What's the benefit over 110v?

tracker1 13y ago

Maybe not, but you could certainly replace recessed canisters, or other fixtures with those that have AC/DC power supplies built in, in such a way that they can have a larger surface in the ceiling/walls or even in the fixture that can then not be part of the "bulb", and subject to the same size constraints.