I have toyed with the idea of a self-sufficient home for energy.
Notwithstanding the cost, almost everything I use can be replaced with
12volt equivelents.  TV, refridgerator, stereos/radios, incandescent lamps,
flourescent lamps, LED lamps, etc, etc, etc.  If you were not too fussy on
the cooking thing, a couple of inverters could provide you with the AC
needed for a microwave, toaster, PC.

HVAC and hot water are a different story.  I suppose a house could be built
into the ground for constant temperature and use an "on-demand" electric hot
water heater (don't some campers use this?).

A nice efficient windmill (or two or three) and/or solar array could keep a
sizeable bank of batteries charged.

I don't think the wiring would have to be changed but a person might want to
change the standard receptacles to a different type.

I have lived comfortably with my family in campers running on 12volt
systems.  However, there were no windmills or solar arrays used here, but a
small gas generator (weed eater motor and car alternator) to recharge every
other day.  And oh yes, the cooking was by campfire or propane (but I only
used 2 car batteries in the camper).

I would like to see this thread continue for a little while.  The
practicality of 12volt system independant of the mains intrigues me.

John

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Florian Voelzke
Sent: Sunday, July 15, 2001 3:58 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [OT]: The 12 Volt Home


Herbert Graf wrote:
>
> I used to think the same about computers but was quickly corrected. It
seems
> that some computer supplies use diode capacitor multipliers in the first
> stage, meaning they would not function with DC, so you do have to be
careful
> here too. TTYL

AFAIK this only applies to 120V mains equipment.
The rectified voltage of 230V~ is about 325V, the output of an active
power factor correction at 230V input is about 430V. To double that
would be too high for the used semiconductors.
But they actually double a 120V input voltage to get equal levels to
230V mains. It seems that the necessary current through the primary
semiconductors at 120V is a bit high and a voltage doubler to 240V makes
things easier. And of course you can sell the same power supply in 120V
and 230V countries by adding a simple small switch.

Other problems of using DC and not AC could be the active power
correction of high quality pc power supplies (it assumes sinusodial
input voltage to control current drawn from mains) and of course any
convential monitor degaussing (like another member of PICLIST mentioned
some time ago).

Florian

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