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So Where’s My Low Voltage DC Wall Socket?

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Re: So Where’s My Low Voltage DC Wall Socket?

#101

Post by hyperman1 »

MisterTea wrote: post #72
mschuster91 wrote: post #57

Earlier quoted context omitted.

> A better solution would be to get everyone on board with a single DC voltage and connector Why? For many things 6V is enough as it will downscale without too much loss to 5V/3V3 which is what most electronics run on... but everything that draws a boatload of power (computers, laptops, LED strips, ...) will go on 12V up to 24V, so if you want a standard it's either 12 or 24V which will introduce a lot of regulation…

Why? Routers, switches, small embedded computers, and a myriad of devices already use 12-24V DC and step it down internally to 3.3V or less for chip use. Laptops and even phones/tablets are no different. And conversion losses don't increase with voltage so long as you design your DC-DC converter properly. 5-6V is fine for small loads of around 10 watts but you then have to deal with line losses. A 5 m / 16 foot 24 AW…

That's true. My aging but still well-functioning WRT54G router had its 12V 2A wall wart die on me last year. At the same time, some USB cable had its micro B end accidentally ripped of.

So I thought, why not, opened the router,and lo and behold, the DC circuit is perfectly happy with 5V and 1.2A or so, and converts it down to I believe 3.3V.

So I drilled a hole in the router and soldered the working end of the damaged cable to the power input. Other end is pluggend into the useless USB TV port. Has been working fine ever since. Neither TV nor router runs hot, which I couldn't say about the old wall wart.

In theory, USB should negotiate the required amount of power It turns out the TV manufacturer decided to simply wire the port directly to the internal 5V rail connected to both USB ports, so it should be able to give at least 2x2A.

Yeah, it was probably cheaper to just buy a new router. Got a bit nerd-sniped there I guess ;-) .

Re: So Where’s My Low Voltage DC Wall Socket?

#102

Post by Johnny555 »

Spooky23 wrote: post #73
Johnny555 wrote: post #12

Earlier quoted context omitted.

If you want one port that can charge multiple devices of varying needs safely, you need smarter cables. Sounds like a reasonable tradeoff. Otherwise every single cable would have to be built to handle the highest possible power delivery rate (100W for USB-C).

The problem lies in that you're pushing the problem into the hands of anonymous cable makers and clueless end users. It's really difficult to stick a standard plug into a 30 amp socket. It's really easy to buy some substandard USB-C cable that lies about it's capability.

The same issue would exist with any universal in-wall DC power supply -- if consumers buy a substandard product, it can destroy their device. Unless you want separate ports different voltage/power output then the user has to buy separate cables for each one.

Re: So Where’s My Low Voltage DC Wall Socket?

#103

Post by neuralRiot »

testplzdeleteme wrote: post #75
Wowfunhappy wrote: post #61

Earlier quoted context omitted.

Wouldn't it be more efficient to have e.g. one DC power supply for the house that can power everything that needs DC power, instead of lots of individual (and likely cheap/inefficient) power supplies?

EDIT: Most consumer appliances will still need there own power supplies. You would still want a last step DC transform to house at a high voltage. If the appliance operates at the voltage DC then it would need no power supply. Yes, and cheaper to build! You can achieve the same efficiency with DC and AC do not directly effect efficiency across the line contrary to popular belief. It is simple about what the voltage a…

>Yes, and cheaper to build! You can achieve the same efficiency with DC and AC do not directly effect efficiency across the line contrary to popular belief.

In fact there are higher loses with AC power transport (specially in long distances) due to the parasitic capacitance of the lines, that’s why some countries use DC power transport lines now.

Re: So Where’s My Low Voltage DC Wall Socket?

#104

Post by Scipio_Afri »

hyperman1 wrote: post #101
MisterTea wrote: post #72

Earlier quoted context omitted.

Why? Routers, switches, small embedded computers, and a myriad of devices already use 12-24V DC and step it down internally to 3.3V or less for chip use. Laptops and even phones/tablets are no different. And conversion losses don't increase with voltage so long as you design your DC-DC converter properly. 5-6V is fine for small loads of around 10 watts but you then have to deal with line losses. A 5 m / 16 foot 24 AW…

That's true. My aging but still well-functioning WRT54G router had its 12V 2A wall wart die on me last year. At the same time, some USB cable had its micro B end accidentally ripped of. So I thought, why not, opened the router,and lo and behold, the DC circuit is perfectly happy with 5V and 1.2A or so, and converts it down to I believe 3.3V. So I drilled a hole in the router and soldered the working end of the damage…

Should've let this thing die. Do you actually have devices hooked up to this.. the speeds you're getting and the likely security holes you have (especially if you don't have this properly behind some other device) are concerning me.

Re: So Where’s My Low Voltage DC Wall Socket?

#105

Post by hyperman1 »

Scipio_Afri wrote: post #104
hyperman1 wrote: post #101

Earlier quoted context omitted.

That's true. My aging but still well-functioning WRT54G router had its 12V 2A wall wart die on me last year. At the same time, some USB cable had its micro B end accidentally ripped of. So I thought, why not, opened the router,and lo and behold, the DC circuit is perfectly happy with 5V and 1.2A or so, and converts it down to I believe 3.3V. So I drilled a hole in the router and soldered the working end of the damage…

Should've let this thing die. Do you actually have devices hooked up to this.. the speeds you're getting and the likely security holes you have (especially if you don't have this properly behind some other device) are concerning me.

Dont worry, there is a decent enough firewall built in to the ISP modem. And my ISP is more than slow enough that the speed of the router doesnt matter much. And when all my computers are off, so are the router, the modem, the TV and all the other stuff.

Re: So Where’s My Low Voltage DC Wall Socket?

#106

Post by 205guy »

I think that with low power LED lighting, as well as all rechargeable devices, there is a case for some (not all) 12VDC sockets around the house (and cars/vans/RVs). Actually, I think mobile applications will be first: in an RV, it makes no sense to have a big inverter to take your 12V batteries to 120V AC, just to plug in wall warts to charge to camera, phone, etc.

I have a friend who installed 12V in parts of his house, backed by a solar charged battery system. See my previous comment for some details:

https://news.ycombinator.com/item?id=21109247

Talking to this friend, we discussed the same problem as the OP. In RVs that are wired for battery power, they use wall-mounted cigarette lighter plugs, and you can buy some small appliances that use them. They are ugly and take up too much space, it would be so much better to have a plug of a regular shape and size. Of course it has to be polarized for DC, so something like ( - | ).

There is also the problem of breaking the arc in DC, so one prong needs to be longer and making contact further in so it can't arc outside the plug. Or maybe it needs some internal mechanism such as plastic slot covers that close and break the ark (like child-protected sockets have now). Anyway it definitely needs some research and design, but I think it would be cool to have a new 12VDC standard plug, then people could start designing products that use it to get the whole ecosystem started.

Re: So Where’s My Low Voltage DC Wall Socket?

#107

Post by rhinoceraptor »

mixmastamyk wrote: post #100
djrogers wrote: post #77

Earlier quoted context omitted.

Why wait for the iPhone 12? The current iPhone already charges significantly faster over USB-C than USB-A, as do all iPads released in the past ~3 years.

I read here recently that fast charging is bad for batteries.

There's really no reason to worry about it. Battery replacements (at least from Apple) are $70, and all modern phones have sophisticated battery management controllers.

Also, fast charging your battery more often could be better since you're not fully discharging and recharging your battery.

Re: So Where’s My Low Voltage DC Wall Socket?

#109

Post by nybble41 »

iamnothere wrote: post #81
kjs3 wrote: post #55

The solar/RV/golfcart world has and entire ecosystem of standardized 12v DC power distribution and the appliances that use it if you really feel the need to have DC. Works pretty good...last year wired up a friends mountain cabin with 12v solar, batteries, inverter for AC, led lights, fans, dorm room sized DC fridge. Different manufacturers and everything popped together fine.

Most laptops can be charged from 12V auto-style sockets as well. 12V DC is fantastic for a solar setup (vacation cabin, off-grid home, or whatever). You can still have some standard AC outlets using an inverter, but there's no reason to have lights running off of AC -- especially if you have LEDs! Since inverters cause a slow but constant power drain, it makes sense to leave them off most of the time. Edit: I also wa…

Keep in mind that your typical RV refrigerator capable of running on AC or propane, and possibly DC, will run much less efficiently on electric power than a standard electric refrigerator. That might make them less-than-ideal for a solar + battery configuration. In an RV context one typically uses the electric mode only when connected to "shore power", where the lower efficiency is less of an issue.

Propane-based refrigerators use an absorption cycle which depends on heat produced by burning the propane; in electric mode they just substitute resistive heating. A pure electric refrigerator would use a compressor-driven heat pump, which is considerably more efficient.

Re: So Where’s My Low Voltage DC Wall Socket?

#110

Post by Thetawaves »

ci5er wrote: post #89
mschuster91 wrote: post #57

Earlier quoted context omitted.

> A better solution would be to get everyone on board with a single DC voltage and connector Why? For many things 6V is enough as it will downscale without too much loss to 5V/3V3 which is what most electronics run on... but everything that draws a boatload of power (computers, laptops, LED strips, ...) will go on 12V up to 24V, so if you want a standard it's either 12 or 24V which will introduce a lot of regulation…

Assuming you mean 5V or 3V DC, there will have to be a baseline level, then it will have to be upconverted or downconverted from the wall AC is (to whatever their baseline standard is in DC), then converted back to AC by X-converting then converting to something in AC, then downconverting to DC OR using semiconductors that used to be expensive (don't know if they still are). Seems complicated. Why not just stick with…

The problem with starting from a low voltage is that even low power levels result in significant current requiring the use of large conductors - or at least a connector capable of supporting those conductors when needed.
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