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Slow Electricity: The Return of DC Power? (2016)

lowtechmagazine.com

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Re: Slow Electricity: The Return of DC Power? (2016)

#11

Post by danielsju6 »

monitron wrote: post #3

We're currently in the process of designing a house that we hope to build early next year. One thing that I dream of doing is lighting the entire house with LEDs wired in a low voltage DC "network." Even better if they're addressable, dimmable, even RGB recolorable. Power over Ethernet would be a pretty cool way of doing it if it was practical...that way you get the data to control the lights as well as the power to…

Ubiquiti has POE panel LEDs https://unifi-led.ui.com/ Obviously geared towards offices. I’m sure there are other options.

I’m also looking at whole house USB-PD, https://voltekinc.com/dc-power-advantage/

Re: Slow Electricity: The Return of DC Power? (2016)

#12

Post by pomian »

monitron wrote: post #3

We're currently in the process of designing a house that we hope to build early next year. One thing that I dream of doing is lighting the entire house with LEDs wired in a low voltage DC "network." Even better if they're addressable, dimmable, even RGB recolorable. Power over Ethernet would be a pretty cool way of doing it if it was practical...that way you get the data to control the lights as well as the power to…

Look into country cabins, boats and campers. Especially the first though. Many are built with only solar for power. They have 12 volt wiring for 12v lights, and 12v outlets. The only AC is if someone plugs in an inverter to a 12v outlet. If course there are many builds with a main inverter next to the ' battery shack', and often 110 AC wiring from that. But there is a lot of information about pure 12v systems, and it is very doable. The problem is if you are not doing it yourself and are in a city, to find a contractor. If you do a dual setup - I suggest using a different colour of wiring, for the 12v system. ;)

Re: Slow Electricity: The Return of DC Power? (2016)

#14

Post by dheera »

__MatrixMan__ wrote: post #13

If it means less time spent in a mess of wires trying to figure out which adapter brick is squealing, I'm all for it.

But please, please, PLEASE design a better connector than fragile USB-C.

120VAC plugs e.g. standard IEC computer power plugs can be hit with bricks and rammed into furniture while they are plugged in and they won't get damaged. All forces of impact get transferred to the chassis, not the PCB. That's good design.

I break about a USB-C cable a week because they just aren't designed for the ruggedness that consumer use cases demand, which are typically higher than military.

Re: Slow Electricity: The Return of DC Power? (2016)

#15

Post by mdorazio »

monitron wrote: post #3

We're currently in the process of designing a house that we hope to build early next year. One thing that I dream of doing is lighting the entire house with LEDs wired in a low voltage DC "network." Even better if they're addressable, dimmable, even RGB recolorable. Power over Ethernet would be a pretty cool way of doing it if it was practical...that way you get the data to control the lights as well as the power to…

Other commenters here haven't really provided any good data to show the issue. If you want to run, say, 10A at 24V through DC wire on a circuit you end up needing stupidly thick wire (~6AWG) to avoid voltage drops over just 100ft. There are charts available to show you, for example [1]. If you're thinking of running normal hobby wire for 12V circuits around a house, the resistance losses are going to be huge.

[1] https://www.boatus.com/expert-advice/expert-advice-archive/2...

Re: Slow Electricity: The Return of DC Power? (2016)

#17

Post by gwbas1c »

monitron wrote: post #3

We're currently in the process of designing a house that we hope to build early next year. One thing that I dream of doing is lighting the entire house with LEDs wired in a low voltage DC "network." Even better if they're addressable, dimmable, even RGB recolorable. Power over Ethernet would be a pretty cool way of doing it if it was practical...that way you get the data to control the lights as well as the power to…

My house was built in 2018. The smoke alarms are low voltage. I remember the electrician, who installed them, told me they are DC.

Thermostats and doorbells are low-voltage AC. The transformer is standard. If you can find 24-volt AC lights, an open-minded electrician should be able to figure it out.

Related: My old house built in the 1960s had an intercom system that was ripped out by a previous owner. I found a warm transformer attached to a bare bulb light socket in the basement with nothing else running from it. I happily removed it.

Re: Slow Electricity: The Return of DC Power? (2016)

#18

Post by malchow »

Solar energy is cheap, as in $0.03/kWhr. (PG&E charges you $0.30/kHWhr.)

The best inverters convert solar DC to household AC at 97.6 % efficiency. [1]

Adding more solar is a question of adding another panel.

The inversion loss is a small price to pay for safe power. [2]

DC is probably not coming back as a way to wire houses and buildings.

[1] https://www4.enphase.com/sites/default/files/downloads/suppo...

[2] https://www.businessinsider.com/tesla-solar-panel-fires-beco...

Re: Slow Electricity: The Return of DC Power? (2016)

#19

Post by axiolite »

Johnny555 wrote: post #16

An LED doesn't run on 24V DC, what's the difference in efficiency between an LED lamp that runs off 120V AC and one that runs off 24V DC?

> An LED doesn't run on 24V DC

It can. Cree's JR5050 24‐V LEDs run on 24V. They have 30V and 36V versions as well.

Re: Slow Electricity: The Return of DC Power? (2016)

#20

Post by gwbas1c »

If you read to the end... This kind of system only makes sense where there aren't major appliances. (Think RVs, off-grid cottages, and developing countries.)

I wonder what would happen if we redesigned the grid today? Would it be AC or DC? If AC, would it be a higher frequency? (Smaller transformers) Is modern DC-DC voltage conversation easier than AC-DC? What voltages would we use?

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