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Crazy explosion in number of wall wart power supplies, all using phantom power, is there an open solution?


(Xenek) #1

Hi,

Like many others, I have a crazy number of wall warts to drive everything I use at home. Just downstairs I count 28 of the things. :frowning:

I’ve been thinking of building a little 18650 charge controller, and when googling, come up against all the powerwalls. It’s just sad thinking of putting in solar and a power wall, just to attach 28 likely inefficient wall wart power supplies that are totally dumb and require 8 240v power boards to fit. Half of them are dev devices from overseas (like my odroid XU4) so I have an annoying number of very dodgy AC gender benders as well.

Is there any project or solution or guide I can follow to try build a ‘wall wart replacement’ that uses a small power-wall style power source? I’m just thinking a modular fully computer controlled powerwall that does DC-DC conversion with full monitoring might help.

If it was an open source community project, all the better, as it would probably lead to a range of commercial products after a few years - I’m looking at banggood.com style products to keep entry requirements very low so people can learn about power supply math without burning cash (me).

I’ve seen this

As a side note, if it looks like this:

Input battery output
DC / AC / Solar multiple balanced 18650 cells computer controlled DC up to 24 volts & 6A

It would serve not just as a UPS or battery backup / charger for all the devices,
but could do smart things like turn off high power consuming device (such as file servers) if AC goes down or solar is broken or off for an extended time) or report on devices that are turned off or no longer consuming power.

The same circuit and system could be tiny, to just make a legal low-voltage Raspberry Pi UPS with web interface & notifications, or huge, to use a real powerwall DC output to control eg. 20 DC devices all with different voltage and current requirements.

I’m maybe imagining 20 of these, but also with MQTT output & input, as well as a low power display of v/A.
https://www.jaycar.com.au/arduino-compatible-dc-dc-boost-module-with-display/p/XC4609

Anyway, maybe forget the crazy future dreams, if you know of any simple Arduino chips and charge controllers and DC-DC converters that I could buy cheap to help create something semi-modular to share, let me know. Throw me links and I’ll start to solder and copy/paste/mod code and share if I get anywhere.

Also ref


http://green-plug.co.uk/ (seems defunct?)

Edited post title - BT


(Derek Boyd) #2

Good post, with no easy answer unfortunately… I’ve wondered in the past about installing 24V DC around the house with DC-DC converters where required, powered by a secondary solar panel and batteries, but never got around to it. I do however use every spare USB socket on the various 24/7 RasPis and routers in the house for displays, phone charging, powering weather station, EmonGLCD etc. Even our alarm clock has a USB socket for firmware upgrades, which my wife uses to charge a FitBit - but we still end up with wall warts.


(stephen krywenko) #3

yeah phantom power consumption especially noticeable the more efficient you make you infrastructure. 15 - 30% of my power usage is phantom power today . because nothing today turns off anymore. i bought smart power switches and stuff which helps to certain degree . but anyways you can buy wall mount USB outlet get rid of your warts but it does not really combat phantom it probably adding to it … the only way to combat that Phantom power issue is to wire in a lower power circuit as mentioned . say using Ethernet wall mounts and the POE to centralized location. and using the smart switching of a POE switch to handle the power requirements - would be no need of building code changes. and build a small adapter plate with voltage regulator that when you pull out or insert the USB it open or closes the circuit and allows the poe switch power management to take over.


(stephen krywenko) #4

that a crazy price to pay – here a buck converters but they also have in boost for about the same prices

https://www.aliexpress.com/wholesale?initiative_id=SB_20180430092818&site=glo&g=y&SearchText=buck+converter&page=2


(Xenek) #5

given the physical size/profile of a wall wart, it’s a bit funny to think you would (in a solar future) step your DC from the powerwall up to 240, then back down to 5v, not once, but for every wall wart. For the average person, using a wall wart isn’t an issue, and is simple, reliable and probably somewhat efficient, but for me it’s a real frustration. With the need to use overseas gender bender plugs there are physical size issues, plug reliability issues, and safety issues. And many devices don’t even get supplied with a charger today, or thankfully, the supply/charger is optional.

Most of my devices are around 5 v, but have differing precise requirements. Eg. My Odroid, Pine64 and Raspberry Pi 3 all have slightly different volt and Amp requirements. It’d be good to dial this up electronically from a web app I could access from any PC, phone or tablet in the house.


(Xenek) #6

I like the idea of smart switches for lights and fans especially - lights are either on or off, fans can have logic applied to them. The draw of a tiny MCU and radio for a smart switch is probably lower than the energy cost of leaving things on.

In my case I’ve centralized nearly all my devices needing AC to DC adaptors into two areas - an IT area on top of the refrigerator for servers, routers, modems, disks, hubs, wifi APs, etc. And the TV cabinet area for the media playback devices, Roku, 12v Amp, Kids Pi’s, voice controllers, and chargers for phones & tablets etc.

So, I’ve probably no need to wire in a 24 DC supply - I just need a couple of good DC-DC distribution boards that are eg. IoT devices. I’d like solar, but don’t have it today, so for me it would be 2 x 240 volt to 24v very high efficiency power supplies that then have controllable DC-DC converters for each device usually needing a wall-wart.

Over the coming weeks to months I’ll see if I can describe some ideas better, and get some rough pricing - I’m imagining cheapest would be to use a PC desktop PSU for the main 240-DC supply - this gives 12 and 5 at high efficiency and low cost. But what do I do for the devices that need eg. 15v or 19v? My guess is I start with a budget PC PSU for the main DC, the use some variable LDO regulators or the like for the devices around 5 Volts (most common) and the devices around 12 volts (less common)

Maybe I should try doing some mockups in LTSpice like they do here.

http://www.microchip.com/forums/m688260.aspx