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Whole house "battery" wiring/power...

Discussion in 'Electrical Engineering' started by Bill, Sep 28, 2009.

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  1. Bill

    Bill Guest

    How about getting rid of all those batteries in various devices in the home
    and connecting the battery connections to one central battery?

    That is to run separate wires when wiring a home and these would carry say
    12 volts DC. There would be a central large battery and battery charger like
    the type used in a computer UPS.

    Then at each electronic gizmo which needs a battery, use a "battery
    eliminator" along with a voltage regulator to supply it with the correct
    voltage. And plug this into a nearby 12 volts DC "outlet".

    This could provide battery power to smoke detectors, carbon monoxide
    detectors, HVAC thermostat, security system, clocks, digital thermometers,
    computer UPS, phone answering machine, etc.

    Then only ONE battery to worry about...

    A 9 volt battery eliminator picture...
  2. EXT

    EXT Guest

    That means my camera, TV remote controls and many other items would revert
    to "wired", each with a wire running to a plug!!!!!!!! No way!!!!!!!!
  3. Jules

    Jules Guest

    When I was thinking about this, I was going to put a bank of inexpensive
    (relatively) car/truck batteries in a dedicated vented area out behind my
    workshop and potentially move to 24VDC rather than 12 due to the losses
    involved in low-voltage DC appls over any kind of distance (initially
    testing just for the workshop, and if successful wiring the house, too).

    Charging / supplemental power could be via all sorts of means, of course.
    The problem is that you'll either have the inefficiency of running DC-DC
    convertors all over the place, or in hacking your devices to better match
    them to the available power (lots of stuff does the regulation on-board
    rather than in the wall-wart).

    Personally I was thinking along the lines of doing it to power some of
    the lighting and things like my laptop which can be easily adapted, but
    it wouldn't be possible to completely switch off the AC supply at present
    - but maybe one day there'll be a standard for low-voltage DC outlets and
    devices will be available that'll just use them.


  4. Jules

    Jules Guest

    One for cell phones is happening - see:
  5. James Sweet

    James Sweet Guest

    Or how about saving all that hassle and just using a switchmode wall
    wart to power each battery operated device? Those are pretty efficient
    these days, and cheap.

    I can't actually think of anything battery powered in my house that
    doesn't require portability, except for my weather station but the
    Eneloops in that go around a year on a charge, and charging those is a
    lot easier than running wires.
  6. James Sweet

    James Sweet Guest

    There already are, have been for decades. Originally they were cigarette
    lighters, but these days plenty are designed as power receptacles only.

    As someone else said, there's far too much loss in 12V to pipe it all
    over the house, you get much higher efficiency by converting the 120 or
    240V already wired at each point of use.
  7. James Sweet

    James Sweet Guest

    There's only a handful of different voltages in common use. Most stuff
    is 5V, 9V, or 12V, with 5 and 12 being the most common.

    I save wall warts and reuse them all the time, I don't think we need a
    law to mandate they all be the same.
  8. krw

    krw Guest

    Hmm, I generally use batteries for *PORTABLE* devices. The stuff that
    sits in one place is all AC operated. I think your idea needs work.
  9. James Sweet

    James Sweet Guest

    The batteries in clocks and thermostats generally last years. Smoke
    alarms are best served by lithium cells which will last 5-10 years. For
    everything else, there's rechargeable cells. They have improved a great
    deal in recent years and I find they work well in nearly everything.

    I got sick of the 9V batteries in my clocks always being dead when I
    needed them so I added a resistor across the isolation diode and
    installed a "9V" NiCD battery in each of them which is trickle charged
    through the resistor. It's been great, I've never had to reset a clock
    after a power outage since.
  10. There is already a trend, in the free market. Lets encourage
    them (as consumers). The last thing the USA needs is more
    federal regulation.

    Christopher A. Young
    Learn more about Jesus

    feds should mandate a wall wort standard, the wide variety
    of them
    clogging the landfills is very wasteful. all wall wart
    devices could
    be designed to accept a standard voltage.,....... same for a
    phone charger standard to cut down on trash
  11. Bill

    Bill Guest

    "bob haller" wrote in message
    That is another interesting idea!

    Many "wall warts" provide DC to all these electronic gizmos. So perhaps
    connect these to the DC system - do away with the "wall warts".

    So the central battery would provide battery backup AND DC power to
    electronic gizmos (instead of using wall warts).

    This could help to solve another problem which is voltage surges. The "whole
    house" DC electronic power supply in the home could be well protected from
    voltage surges, thus you don't need surge protectors at every outlet where
    an electronic device is plugged in.

    Also these electronic gizmos would continue to work during power outages.

    As to voltage drop, make the main supply 24 volts DC if necessary. That
    should give you over 12 volts DC at the end of the line.
  12. krw

    krw Guest

    Most have none ;maybe an old clock radio.
    Nope. None here. Both powered off the heat pumps. It doesn't take
    much of a battery to keep a clock going. A button cell should last
    the life of the clock.
    See above. You bought junk.
    Wired is a requirement now.
  13. One problem whigh you might ecounter when powering devices from
    one DC power supply: Ground loop. If you feed everythign with
    one power supply, is is very asy to get noise problems to system
    if those parts were originally designed t work with their wall warts
    what provide isolated power. Then worst case would be if one equipment
    would have - side grounded to case and other one + connected to case...
    There are whole house surge protectors that plug to main electrical
    panel. The DC power distribution system on the other hand could have
    it's own surges when things are plugged in and out...
    24V distributed around and locally converted to 12V or whatever needed
    is a working idea. A suitable switch mode power supply circuit could do
    that (and provide isolation if needed). The problem here is that you
    need that small converter box near the outlet.. not much different from
    small switch mode type wall wart in size. If you plan to hide those
    things inside wall electrical box, then it would not be much different
    than having the wall warts hidden somewhere inside the wall
    (many same problems).
  14. Indeed. Many things have proprietary wall warts anyway, with ferrite stubs
    (like my turntable/RIAA preamp compo, each came with its own 16 V wall
    wart;the preamp, a Cambridge Audio ( 540 PP moving
    magnet preamp, 16 V with a ferrit stub, the turntable, a Pro-ject
    (www.project-audio.com_ )Debut III with a physically (and probably
    electrically) same 16 V wall wart, with the same male jack, but without a
    ferrit stub). The only place I've seen that has a dc grid, is a 300 MW steam
    power station, fossil fired with brown coal, but I have forgotten the
    details, since it's been 15 years or so. It's in Kozani, west macedonia (not
    the country, province of Greece). They needed it for the excitation circuits
    of the main alternators. While large AC trasformers have a very high
    efficiency (99% at full load) wall warts have a much lower, 50% IIRC. And if
    they're DC/DC it needs more advanced technology. Not mentioning needing
    probably #4 wires for the DC grid of a residence....
  15. Guest

    Remember that 9 volts will loose voltage in a short run. By
    the time you get it trough a wire from one end of the house to
    another, you might be down to 7 volts and that might not work too
  16. Look at the URL, it's for a popup window.

  17. My suggestion would be for a 48 volt DC system. Plain
    old telephone service uses 48 volts DC for battery and
    PoE, power over Ethernet is usually 48 volts DC. The
    wire size could be smaller than that for a lower voltage
    system and the 78xx type regulators are very inexpensive
    and come in a variety of wattage ratings for stepping
    down the voltages. The technology to pull it off is not
    exotic and can be done with all off the shelf parts.
    Solar and wind power could integrate quite easily with
    such a system.

  18. Bill

    Bill Guest

    In my case, basically for higher reliability of some electronic gizmos. Also
    to have pretty much maintenance free electronic gizmos so far as battery
    replacement goes.

    I live in a rural area and the electricity goes out at least twice a

    And I've had problems with phone answering machines which need to have the
    time reset each time the power goes out. Or other models the batteries wear
    out quickly during a power outage. So my phone answering machine needs
    constant attention!

    Then I have about 7 battery operated clocks (due to power outages), 6
    battery electronic thermometers for temperature monitoring because I have a
    wood stove and want to keep an eye on the temperatures when I am in other
    rooms of the house, then about 6 battery smoke detectors / CO detectors
    everywhere (again for wood stove monitoring).

    Basically I frequently need to replace a battery in something. It would be
    nice to have just one central battery and not worry about it except once
    every several years!
  19. krw

    krw Guest

    Think "transformer".
    The maximum "safe" voltage. There is a reason power transmission is
    in the hundreds of KV. AC.
    You really want to waste power, don't you?
    Not everyone wants to waste ten times the power they use.
  20. Do you have the slightest clue of what the discussion
    is about? It's a hypothetical discussion about a DC power
    distribution system for a home. I neither seek to impose
    a standard or ridicule the ideas of others. I do have about
    four decades of experience with all things electrical and
    electronic but sadly, I don't know everything. I wish I did.

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