Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
12V DC to Variable DC, Off-the-shelf solutions?
But then Dell and Apple wouldn't make 5000% markup on their branded accessories
Add Thank You Reply
(12-28-2017, 11:18 PM)John61CT Wrote: Sorry brain fart, can't find the receipt for the 12V ones I bought

Actually, I had not seen these before.  It's a very similar idea to what I brought up about having a "magical" interface where the voltage is automatically selected.

From your link, the connection between the power supply and the plug end has 3 pins.  The output has only two, like any other power supply.  So a good hypothesis would be that there is something in the plug end, most likely a resistor molded in, that allows the supply to adjust the output based on which end is attached.

The idea that was taking shape for me was to have multiple DC power outlets throughout the living space.  Each of these would have variable output, not fixed to any particular voltage.  Every device would have a matching plug but include a means, like a resistor on a third pin, to set the output voltage at the same time the device is plugged in.  This way you can connect any device to any outlet, not having to worry about mismatched voltage.

I think this could be implemented with the DC-DC boards that were suggested earlier, and for less cost than buying a bunch of the ones that come with nice injection molded ends.  As long as the circuit would accept the modification, the voltage setting potentiometer on board could be removed and wires soldered to the board that connect to an externally plugged in resistor.  This resistor would be part of the device's attached plug, perhaps mounted inside the connector housing/shell.  To work, the output would need to be 0V with the potentiometer removed.  It would also need to stabilize the output voltage very quickly upon connection.

Sound doable?  Useful idea to anyone else?  Potential pitfalls?
What doesn't kill me makes me smarter
Add Thank You Reply
A lot of electronic devices that operate on DC, and some devices that operate from wall-warts or power bricks automatically adjust to the input voltage. It's quite common for laptop bricks to even state on the label something like "Input Voltage 110-240 VAC". 

Many solar controllers test the voltage of the battery bank when first hooked up to determine if its a 12v or 24v bank. 

Lots of modern high brightness LED emitters have small built-in regulators that regulate the voltage on the chip to exactly what it needs, no matter if the input is 5 volts or up to maybe 15-20 volts. 

Of course the assumption here is that the devices you want to power, want what they want...and nothing else will do.

If you accidentally feed 20 volts directly into the bottom of that expensive iPhone, it probably won't like it very much!
About to be 'vanless' after FOUR years...
Add Thank You Reply
(12-28-2017, 06:03 PM)WanderingCanuck Wrote: Your list is similar so far to the DC devices I'd want to power, though mine includes some other things to charge like hair clippers (4.5V/1A), a VHF radio (6V/0.5A), maybe a wireless router (9V/0.6A), and perhaps a few more.

What do you still run off the inverter?

My small (550 watts MSW inverter) supplies a power strip that my FRS radio charger base, hair trimmer, satellite receiver, etc. are plugged into.  These are all small loads and I could have gone with a smaller inverter, but doesn't seem to be a problem as I have 250Ah of battery and 400 watts of solar and a generator to back it all up if needed.  My suggestion is buy the biggest solar system/battery setup you can afford and don't sweat it.  Just try to run as much of the stuff as you can with least amount of step up/down of voltages.  The double conversion process is wasteful.  Here is the desktop I carry, .  It runs off the laptop 12VDC adapter that converts to 19.5 VDC.  

"...maybe a wireless router (9V/0.6A)...".  My hotspots have routers built into them with a maximum of 5 devices (ip addresses) connected, but this is all wifi connections.  If you need the faster ethernet ports for moving large amounts of data, a seperate router is feasible.  You are talking very small power loads.

No need to reinvent the wheel when the technology is mature on what works now.  I do believe that in the future, there may end up being the technology to plug in devices that would communicate to the source what they require for power.  Not there yet.  Invent it and become rich beyond your wildest dreams. Big Grin Big Grin Big Grin

Good luck.

2000 Roadtrek 200 Versatile "The Beast" (it has been tamed hopefully)  I feed it and it doesn't bite me.
Add Thank You Reply
(12-28-2017, 11:44 PM)WanderingCanuck Wrote: The output has only two, 

Actually some of those DC plugs has three connections. 

The outside of the big round ring, the inside of the big round ring, and a center pin. 

So on those units the PC and the power supply actually talk to each other. I don't know the protocol or what they talk about, but I do know that it usually is more advanced than the Apple style where it is just measuring a resistor.
Add Thank You Reply

Forum Jump:

Users browsing this thread: 1 Guest(s)

Powered By MyBB, © 2002-2018 MyBB Group.