Sensibly Powering DC Technology? 90
splatnet asks: "Having upgraded my PC to a Mac Mini all my IT kit is now DC. The Mini, my flatscreen, external USB HDD, USB DVD writer, JBL speakers, ADSL/Wireless Router. I have practically the same amount of space taken up for transformers as I do computer equipment! Has anyone found/invented a way to power multiple DC devices (all with slightly different power requirements)? I'm thinking in terms of space/convenience/running costs etc." It would be neat if there was a DC power source that could be tuned to a specific voltage, as well as modular plugs to fit your various devices. Is there anything out there that comes close?
Guitarists might have some ideas (Score:4, Interesting)
Contact someone who puts together racks of FX for guitarists/stage musicians?
Re:Yes (Score:1, Interesting)
My high-school electronics lab used a powersupply from an old IBM PC to provide power to an entire room of students. It was perfect for all the 12V ICs, etc.
Re:Guitarists might have some ideas (Score:3, Interesting)
Somewhere, I saw an interview with the sound/tech guy for one of those bands that is a vaguely electronic pop/rock band. (It wasn't Radiohead, but it was some similar band.) They had a whole 9U rack devoted to a power solution for the whole band. It had a power conditioner in it, as well as a serious UPS. It provided clean power for the whole band, across a whole range of DC voltages, in different amperages, as well as AC. I priced out JUST those parts that were commercially available, not even counting the homebrew stuff, and it worked out to be something like fifteen hundred dollars.
So, the answer to your Ask Slashdot?
"Get rich & famous, then hire somebody else to tame your cables."
No! (Score:2, Interesting)
The closest consumer solution (Score:3, Interesting)
What makes the iGo solution work is the "tips" which apparently provide feedback to the DC-DC voltage regulators as to what the desired voltage for that tip is.
What makes it suck is that you can only have two "tips", and it has so many cords that it is almost worse than the original two wall warts you had to carry around.
My solution would be to reverse-engineer an iGo system, have a common high voltage DC bus and modular DC-DC regulators that can stack, with integrated ports for additional cords and "tips". It isn't perfect; you still have way more cords than a sane person would want, and if your device requires multiple voltages (I think the mac mini is in this category) you will need to do something fancier...
Re:Requirements (Score:3, Interesting)
I'm envisioning something like this, assuming 1.5 volts per cell (should be obtainable with the right industrial deep-cycle batts):
[okay, that was anticlimactic. I just spent 10 minutes trying to get slashcode to take my ASCII art and failed miserably. Any ASCII art experts care to respond with tips on how to make it work?]
You could come within
What's wrong with doing it this way?
Re:Requirements (Score:2, Interesting)
Auto-voltage selection magical box in the corner (Score:3, Interesting)
This power supply could provide a few hundred watts, run off any voltage (AC or DC) to step (buck or boost) and switch [altera.com] (provided the current on the supply side is available) to the proper output voltage. 3-6 wires and some sort of universal plug would be sufficient to provide a serial comms link and power/ground for a few different supplies to a number of devices.
I can imagine having to buy a large one for your computer desk, and maybe a smaller one for your phone/answering machine/etc. (If they're still around).
The connectors should be bisexual so you can connect a number of cords together without worrying about which end is which (or having to buy matched pairs and end up with extras for DIYers) to get to your device. Feedback from the device on power quality or voltage drop would be nice (expensive however) to compensate at the supply for bad contacts or extra long runs.
NatSemi will eventually come out with an integrated controller that takes care of the signaling (including PHY), all control functions, and the kitchen sink - all somebody has to do is provide the transformer, diodes, filter caps, and case. This will make these easy to manufacture and then companies can compete on form factor, efficiency and cost rather than trying to get you to buy their proprietary cables and yet another wall wart for your [whatever].
A controller that could plug into a spare ATX power supply that would properly load it and provide a number of different voltages and a cabling system with converters to a number of different barrel connector sizes and polarities would be nice
Re:Forget it (Score:3, Interesting)
The insurance industry doesn't quite work that way.
You can burn down your house by misusing matches (or a propane torch, or a hand grenade) and you'll still get your insurance adjustment. As long as you don't do it ON PURPOSE you're covered. That means if you accidentally knock the lit candle into the paper-shredder-basket, it's covered. If you trip over the cat and do the same thing, you're still covered. But if you decide, "Hey, I don't like my stuff anymore!" and do it on purpose, you're not covered.
This leaves aside the stupidity of purposefully burning down your own house. Most policies cover 80% of actual (demonstrated) losses, with some very-much-higher priced policies covering 80% of replacement costs. In both cases you have to prove what you owned. This is usually quite difficult to reconstruct from ashes. One good trip 30-minute around the house with a video recorder and sending the tape to your favorite sibling/parent/safe-deposit-box supposedly means the difference between getting bubkus and actually being able to state (and prove!) you owned relatively new 25 button-down shirts at 50% of their expected lifespan at $30 each = $15 * 25 *
Remember the reimbursement price for lots of things is basically garage-sale prices, which isn't much considering you'll have to go out and actually find it all again.
Fires suck. Insurance sucks, too, except when you need it, and then it's the best thing there ever was. I dated a gal a long time ago that lost everything in a tornado. She got new stuff, but not very much of it, and she lost all the pics she'd ever taken, etc.
So: It's okay to solder your own Power Supply. It's okay with your insurance company (probably, IIRC) to use it. But, it's wise to test the sucker and probably leave it plugged in for a couple of days on a concrete floor with no combustibles around and a good circuit breaker protecting things.
My advice: Simplify things. Buy a set of 5 outlet strips, use the provided screws to affix them to a piece of plywood, plug them into each other (cascade them; they have built in circuit breakers themselves), plug all your bricks into this arrangement, and put a very nice smoke detector right over the whole thing.
Solar enthusiasts (Score:4, Interesting)
This is a problem that will not be solved. (Score:3, Interesting)
No manufacturer is going to take this on because of the customer service issues, even if liability wasn't a problem.
Further, it would have to be mass produced to even approach the cost of buying seperate bricks, and many, if not most, consumers would rather save the 20% increase and deal with a few extra bricks.
Finally, such a supply could not be nearly as efficient as seperate bricks and still be remotely cost effective. The most efficient supplies are switching power supplies. The most efficient switching power supplies are fixed voltage, and have a peak efficiency at a particular current. Each brick is designed for the device it powers. While one can design an adjustable output supply it is optimizable for one voltage and one current - the rest of the range is very poor. This makes for a hotter brick, nevermind the cost of the additional electricity.
The best option is to have a universal supply at one voltage which can easily be converted by the target device into the power that it needs.
This is called AC distribution, and works quite well.
The real problems are consumers who complain to manufacturers that they want light/smaller/portable devices, and manufacturers who fulfill those requests by taking the AC power converter out of the device.
No, we're not going to run DC around the house because you either need high DC voltages (which can be more dangerous than AC due to muscle dynamics) or high currents which are a greater fire hazard.
No, we're not going to create a 'universal power supply' because universal for you is not universal for joe average, and even if you would be willing to pay $300 to power 5 devices, it's not a mass market item.
No, manufacturers aren't going to put the power supply back in the laptop/cellphone/monitor/etc. It's cheaper with the bricks, and they can sell worldwide with different bricks instead of completely different parts.
-Adam