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adrrtoday at 1:57 AM9 repliesview on HN

Our houses should be DC. So wasteful to have all these bricks to change to AC to DC.


Replies

bigiaintoday at 2:11 AM

Sure, maybe?

If your house gets 800V DC you're still gonna need "bricks" to convert that to 5VDC of 12VDC (or maybe 19VDC) that most of the things that currently have "bricks" need.

And if your house gets lower voltage DC, you're gonna have the problem of worth-stealing sized wiring to run your stove, water heater, or car charger.

I reckon it'd be nice to have USB C PD ports everywhere I have a 220VAC power point, but 5 years ago that'd have been a USB type A port - and even now those'd be getting close to useless. We use a Type I (AS/NZS 2112) power point plug here - and that hasn't needed to change in probably a century. I doubt there's ever been a low voltage DC plug/socket standard that's lasted in use for anything like that long - probably the old "car cigarette lighter" 12DC thing? I'm glad I don't have a house full of those.

ericdtoday at 2:01 AM

Something to consider, and something I got a vivid demonstration of while playing with solar panels, DC arcs aren't self-extinguishing, unlike AC arcs. At one point I stuck a voltage probe in, and the arc stuck with it as I pulled the probe away. It also vaporized the metal tip of the probe.

My understanding is that DC breakers are somewhat prone to fires for this reason, too.

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bandramitoday at 2:00 AM

I've worked overseas a lot and one thing that's really different from 2 decades ago is that I simply don't need a step-down transformer anymore because every single thing I plug in converts to DC (or otherwise accepts dual-voltage) anyways. So I have a giant collection of physical plug adapters because every device I use just needs to fit into the socket and takes care of it from there.

(My stand mixer is the lone sad exception)

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torginustoday at 2:06 AM

I've had discussed with people familiar with the matter, and they convinced me its really not worth it for many reasons, the main one being safety - DC arcs are self sustaining - AC voltage constantly goes to zero, so if an arc were to form, it gets auto extinguished when the voltage drops. With DC this never happens, meaing every switch or plug socket can create this nice long arcs and is a potential fire hazard.

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kccqzytoday at 2:02 AM

That’s actually a recent phenomenon. Before the age of electronics most household appliances either worked with AC or DC equally well (like incandescent bulbs) or worked well with AC only given the technology at the time (think anything with a motor, fans, HVAC compressors etc).

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jwilliamstoday at 2:24 AM

There are niches where DC makes sense - low-voltage lighting, USB/LED ecosystems.

Once you get into higher power (laptops and up), switching and distribution get harder, so the advantages fade.

For bigger appliances (fridge, etc), AC is fine + practical.

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flowerthoughtstoday at 5:37 AM

I'm renovating a house, and have been considering 24V or 48V DC outlets in a few rooms. Semiconductors become more expensive above ~32V, so 24V might be the sweetspot.

However, there's also PoE (24 or 48V!), so maybe that's the right approach. It's not like each outlet is going to run a heater anyway.

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epxtoday at 2:25 AM

Having a single big DC converter at a home would help a lot with power factor (LED lamps connected directly to AC have terrible power factor).

Mistletoetoday at 2:36 AM

Modern bricks really aren’t that inefficient though. An Apple charger is like 90% efficient. A DC to DC converter is about that efficient or worse.

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