12V thru house 110V wiring
Mark Fisher
want to remove the feed cable and install solar panels.
Rather than re-wire for 12V, is there amy technical problem with using
the existing in-wall 110V wiring?
Of course, for safety, sockets and lighti fistures will need to be
replaced with 12V versions, or at least relabelled.
Mark Fisher
Martin Brown
> I have a cabin in my backyard that has been wired to the 110V grid. I
> want to remove the feed cable and install solar panels.
>
> Rather than re-wire for 12V, is there amy technical problem with using
> the existing in-wall 110V wiring?
Depends whether or not you mind if your shed burns down.
The current flow in the wires for a fixed power load will be roughly 10x
larger when running at low voltage 12v compared to 110v. The resistive
heat dissipation in the wires I^2R will be 100x more.
A 100W lamp at 110v draws less than an amp, at 12v it draws 8A.
I would do the sums again *very* carefully for solar power if I were
you. It generally is not at all economic if you are already on grid. How
many Ah of batteries needed and what panels & charge controller.
Most times it is a lot cheaper to hump a heavy battery around and charge
it at home than to charge it in situ by solar (or wind) power.
>
> Of course, for safety, sockets and lighti fistures will need to be
> replaced with 12V versions, or at least relabelled.
Provided you don't exceed the total current rating it might be OK. But
remember to use a low voltage automotive fuse in the circuit to protect
against accidental short circuits causing red hot cables.
I saw a very nasty fan heater failure at the weekend - one of those
oscillating ones and the power cable failed by stress fracture on the
wrong side of the thermal cutout protection. It was a filled plastic
chassis construction and well alight when the owner found it.
Regards,
Martin Brown
Mark Fisher
<|||newspam|||@nezumi.demon.co.uk> wrote:
>The current flow in the wires for a fixed power load will be roughly 10x
>larger when running at low voltage 12v compared to 110v. The resistive
>heat dissipation in the wires I^2R will be 100x more.
>
>A 100W lamp at 110v draws less than an amp, at 12v it draws 8A.
>
>I would do the sums again *very* carefully for solar power if I were
>you. It generally is not at all economic if you are already on grid. How
>many Ah of batteries needed and what panels & charge controller.
>
Hmm... maybe I should consider gas lamps and a Sterling engine.
Mark Fisher
hamilton
> On Wed, 02 Mar 2011 09:44:26 +0000, Martin Brown
> <|||newspam|||@nezumi.demon.co.uk> wrote:
>
>
>> The current flow in the wires for a fixed power load will be roughly 10x
>> larger when running at low voltage 12v compared to 110v. The resistive
>> heat dissipation in the wires I^2R will be 100x more.
>>
>> A 100W lamp at 110v draws less than an amp, at 12v it draws 8A.
>>
>> I would do the sums again *very* carefully for solar power if I were
>> you. It generally is not at all economic if you are already on grid. How
>>
>
> Hmm... maybe I should consider gas lamps and a Sterling engine.
>
> Mark Fisher
>
>
>
Just asking.
;-)
Fred Bloggs
Leave wiring and fixtures as is and install an inverter http://www.solaronline.com.au/
John Larkin
Sounds fine to me. If someone plugged a 120v appliance into the 12v
outlet, nothing dramatic would happen. You'll of course have fuses or
breakers somewhere anyhow.
John
PeterD
I can't imagine you'll be producing much more than 20 amps per circuit
so it should work OK. I'd use a breaker panel (or fuses) to limit the
current to an acceptable level. I'm assuming you will 'buffer' with a
deep cycle LA battery, right?
Personally I'd replace the connectors/fixtures with 12V ones, for no
other reason other than you'd be able to control polarity and anything
plugged in won't accidentally be plugged into a 120 V circuit.
--
I'm never going to grow up.
Tim Wescott
That may not be any better than solar.
You should take Martin's point: the wiring is rated for _current_, by
dropping the voltage by a factor of 10 you're reducing the available
power at the socket by a factor of 10, also. If you're willing to live
with that, you'll do fine -- one way to reduce the cost of solar is to
reduce your power consumption.
nospam
>Hmm... maybe I should consider gas lamps and a Sterling engine.
If you are not technically competent to judge the suitability of a bit of
wire you are not technically competent to judge the suitability and cost vs
benefit of grid vs any other form of power generation.
My advice would be to leave the grid connection and wiring intact because
he will almost certainly want to use them in the future.
Batteries alone cost more than the amount of electricity at grid prices
they can charge and discharge in their lifetime.
whit3rd
> On Wed, 02 Mar 2011 08:26:07 GMT, markf...@protocall.com (Mark
> Fisher) wrote:
>
> >I have a cabin in my backyard that has been wired to the 110V grid. I
> >want to remove the feed cable and install solar panels.
> >the existing in-wall 110V wiring? [for 12V DC]
> Sounds fine to me. If someone plugged a 120v appliance into the 12v
> outlet, nothing dramatic would happen.
NOOOO! Any and all AC appliances with transformers may
burn up with 12VDC applied. AC motors likewise will cause high
(fault) currents. The odd 120V light bulb won't explode your
fuses, though.
It may be appealing to consider an auto-style 12V battery for energy
storage, but it's NOT a 'natural' solar-electric component. It makes
no sense to modify a dwelling in favor of 12VDC. Heck, what ARE
the refrigerator options with only 12V available? Or electric blanket?
Spehro Pefhany
wrote:
AFAIUI, RVs typically have 12V systems, including lighting, fans and
water pumps. Fridges, heaters and such like are propane powered but
require 12V for the controllers. It might make sense if your dwelling
_is_ an RV.
Rich Grise
RV/trailer 'fridges are called 3-way; they'll run off 120VAC, 12VDC, or
propane. They use the "ammonia cycle," where heating causes cooling.
There are two heating elements and a little propane burner.
But if _all_ you have is 12V, I wonder if Peltier would be worth looking
into?
Cheers!
Rich
Fred Bloggs
wrote:
> On Wed, 2 Mar 2011 12:25:16 -0800 (PST), whit3rd <whit...@gmail.com>
>
> - Show quoted text -
Makes no sense to change out the wiring of an existing mains powered
dwelling. Inverters are now part and parcel with solar cells, in fact
one manufacturer has gone so far as to create a distributed inverter
technology that is built into the panels, if not the cells themselves,
and is parallelable. The vast majority of the market is geared towards
powering the dwelling load and off loading the excess onto the mains
only for the periods of adequate insolation - with no battery backup
or storage of any kind used or contemplated. Since 12V rquires 10x the
current and therefore 10x cross-sectional area and volume of copper-
this would be what is called an unacceptable carbon footprint and
unsustainable approach to using solar. It is important the OP find a
solar PV inverter, one that incorporates MPP tracking as a minimum,
and not just any old inverter.
Martin Riddle
"whit3rd" <whi...@gmail.com> wrote in message
news:f365a14e-6110-43f3...@glegroupsg2000goo.googlegroups.com...
You could replace the duplex sockets with the 220v ones that have the 90
degree prongs.
Not many plugable 220v appliances here in the US.
Cheers
k...@att.bizzzzzzzzzzzz
wrote:
Hmm, lets see.... Air conditioner, clothes dryer, stove, dust collector,
cabinet saw, air compressor...
Joel Koltner
news:tbltm61ek2qd2iekq...@4ax.com...
> Hmm, lets see.... Air conditioner, clothes dryer, stove, dust collector,
> cabinet saw, air compressor...
...arc welder!
k...@att.bizzzzzzzzzzzz
Not yet. Bandsaw first. ;-)
mike
1) there is no grid available.
2) you derive some personal non-economic benefit, well being,
"hey look what I can do", from being off grid.
You can live in a tent...but unless you are willing to dramatically
decrease your needs for energy, there is no economically feasible
solar system, today. No, the schemes whereby you transfer the cost
to ME thru government subsidy or force the utility to buy electricity
at inflated rates raising MY bill don't count. I don't want to pay for
your system!
The current you can get thru the wiring is the rating on the breaker.
So you get 1/10th the power. Unless your peak load on the circuit
was less than 1/10th the rating, you're gonna have a problem.
See "living in a tent" above.
You don't want to put 12VDC on 110VAC wiring. Plug in a device
with a transformer and sparks will fly. Polarity is important.
Lotsa devices have non-polarized plugs. Call up the local electrical
inspector. If he's on his toes, he won't let you do it.
I can hear the villagers lighting torches to come after me.
"No that can never happen", "I won't tell the inspector", "he
has no jurisdiction", "I'll never have any visitors who might
compromise the system"...Use common sense. Stuff happens.
Put separate 12V wiring in the place, or use an inverter and
the existing AC wiring.
Go visit newsgroups that address these issues for details, but...
Use more than 12V for your DC storage system into the inverter.
Here's how you talk yourself out of the project.
These are round numbers, but the message is the same.
Turn on everything you want to power simultaneously and spend
some quality time with the utility meter. You need at least that
much peak power plus any additional for motor starting peaks etc.
Measure consumption over an average day in the season when you
use the most energy. Multiply that by
how many consecutive cloudy days you want to survive. Times some
efficiency factor. That's how big your batteries need
to be.
Google for insolation charts for where you live. That'll tell you
how much solar energy you can expect to get from a typical winter day.
Divide that by 10 for the efficiencies of the solar system and charging
system and and and...
Divide that number into the average daily energy requirement to see
how many square meters of panel you need.
A popular number is 1KW/square meter. Depending on the efficiency of the
panels and other system components you can afford, you're looking
at 10% of that on a sunny summer day with no buildings or trees
to block any of it. But averaged over the day, it's
a lot less. And in winter it can be near zero depending on where you live.
Add up the installed cost of all that stuff.
Bottom line is that solar power is a fool's errand.
There's no way it can pencil out on an individual basis with current
technology. Unless you can get someone else to pay for it...that would be
me...and I object to my tax dollars fueling your errand.
Wiring is the least of your worries.
Find a different hobby...like convincing the tree-huggers that we
need to get some nukes on line BEFORE we kill off all the trees.
Greegor
> [...] Heck, what ARE
> the refrigerator options with only 12V available?
> Or electric blanket?
There are refrigerators that get their power directly
form Liquid Propane "bottle gas".
Martin Riddle
"Greegor" <gree...@gmail.com> wrote in message
news:e5bb4110-69c1-4c13...@a11g2000pri.googlegroups.com...
Yea 3 way RV fridges, AC, DC & LP gas. I believe they use an Ammonia
refrigerant.
Cheers
Michael A. Terrell
Electric stove, all consumer electronics with automatic 120-240
switching.
--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.
Michael A. Terrell
Over hyped Electric Car! :(
Sjouke Burry
and your wiring gets not loaded with unreasonable currents.
Then put in high efficiency lamps, etc.
But you will need about an acre of sun panels, and 10 or twenty
deep discharge lead battery's.
If you go for an ac invertor, higher battery voltage will be better,
use 24 or 48 volts, and choose an invertor accordingly.
That will provide better battery efficiency and less losses.
Sylvia Else
> On Wed, 02 Mar 2011 08:26:07 GMT, markf...@protocall.com (Mark
> Fisher) wrote:
>
>> I have a cabin in my backyard that has been wired to the 110V grid. I
>> want to remove the feed cable and install solar panels.
>>
>> Rather than re-wire for 12V, is there amy technical problem with using
>> the existing in-wall 110V wiring?
>>
>> Of course, for safety, sockets and lighti fistures will need to be
>> replaced with 12V versions, or at least relabelled.
>>
>> Mark Fisher
>>
>
> Sounds fine to me. If someone plugged a 120v appliance into the 12v
> outlet, nothing dramatic would happen.
What happens when you put 12v DC across a transformer winding designed
for 110V AC?
Sylvia.
John Larkin
If it's a dinky transformer, it might get a little warm. If it's a big
one, it would blow a fuse.
But the best answer is "don't do that."
John
Kevin McMurtrie
markf...@protocall.com (Mark Fisher) wrote:
I thought large solar panels were 16 to 48 volts. I think it would be
easiest to get a mini inverter that produces 120VAC rather than 12VDC.
Some will hook up to storage batteries.
12V is difficult to move any distance because the wire losses are so
high. It wouldn't be practical for more than a few feet.
--
I will not see posts from Google or e-mails from Yahoo because I must
filter them as spam
Phil Hobbs
And if it's a middle-sized one, it might catch fire! (Goldilocks
notwithstanding.)
The other issue is that a voltage drop that wouldn't worry you with 120V
can dim your lights by half at 12V.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net
Bill Bowden
<pcdhSpamMeSensel...@electrooptical.net> wrote:
> John Larkin wrote:
> > On Thu, 03 Mar 2011 13:55:03 +1100, Sylvia Else
> > <syl...@not.here.invalid> wrote:
>
> >> On 3/03/2011 2:13 AM, John Larkin wrote:
> >>> Fisher) wrote:
>
> >>>> I have a cabin in my backyard that has been wired to the 110V grid. I
> >>>> want to remove the feed cable and install solar panels.
>
> >>>> Rather than re-wire for 12V, is there amy technical problem with using
> >>>> the existing in-wall 110V wiring?
>
> >>>> Of course, for safety, sockets and lighti fistures will need to be
> >>>> replaced with 12V versions, or at least relabelled.
>
> >>>> Mark Fisher
>
> >>> Sounds fine to me. If someone plugged a 120v appliance into the 12v
> >>> outlet, nothing dramatic would happen.
>
> >> What happens when you put 12v DC across a transformer winding designed
> >> for 110V AC?
>
> > If it's a dinky transformer, it might get a little warm. If it's a big
> > one, it would blow a fuse.
>
> > But the best answer is "don't do that."
>
> > John
>
> And if it's a middle-sized one, it might catch fire! (Goldilocks
> notwithstanding.)
>
> The other issue is that a voltage drop that wouldn't worry you with 120V
> can dim your lights by half at 12V.
>
Not sure of the standard wire size used for 120 operation, but using
#12 copper wire, you would get 11.2 volts to a 12 volt, 100 watt light
at a distance of 30 feet. Power lost in the wire would be about 6
watts figuring 1.6 milliohms per foot. Probably wouldn't raise the
temperature much with 60 feet of wire. Power to the load would drop
from 100 to 87 watts. How dim is a 100 watt light operating at 87
watts?
-Bill
Phil Hobbs
The rule of thumb is that if you run a light bulb at 90% of rated
voltage, you get 30% less light and three times the life. That's close
to a cubic relationship. So 87% would be roughly 0.87 cubed, or about 65%.
Jasen Betts
> I have a cabin in my backyard that has been wired to the 110V grid. I
> want to remove the feed cable and install solar panels.
>
> Rather than re-wire for 12V, is there amy technical problem with using
> the existing in-wall 110V wiring?
>
> Of course, for safety, sockets and lighti fistures will need to be
> replaced with 12V versions, or at least relabelled.
>
> Mark Fisher
As long as the wiring can handle the current you should be alright.
if you don't replace the outlets label the appliances too. plugging a
110AC appliance into 12DC could burn out motors etc, but plugging a 12V
appliance into 110 is almost certain to be spectacular.
--
⚂⚃ 100% natural
amdaws...@gmail.com
Now on to charging. Efficiency of solar energy is garbage. The only truly efficient system out there to run a 12V to 110V conversion is hydroelectric, but that is a whole nother topic.
Your solar panels will average about 30 percent efficient (only when the sun is shining too) Long explanation short, you will ALWAYS consume faster than you can produce (except for hydroelectric) 2ind solar hybrids are better, but not much. Now if you are off grid, how do you supplement this pitfall? Buy a 90amp deck mount converter, and use a generator too.
I too have a cabin semi off grid. 4 400 watt wind turbines, and everything I just said to get. The beauty of it is, if my batteries begin to get low, I flick a switch and they charge off of my power pole. Also keep in mind this system is not for beginners to build, and it costs about $6000. And no, you won't be reimbursed for it because it isn't an authorized power generation system.
Rheilly Phoull
Winfield Hill
>
> You absolutely do not want to do That! ...
I would say, mostly good advice, although I disagree
with totally trashing solar. It's really a matter
of how many solar panels; my house has enough so
our solar creates more electricity than we consume.
But he's right, a set of solar panels on top of a
trailer or a small cabin cannot be sufficient. My
brother's cabin in NV has a full roof of panels,
and deep-discharge batteries, providing plenty,
but he relies on his generator for heavy-draw
activities and for topping off his batteries.
--
Thanks,
- Win
Martin Brown
> amdaws...@gmail.com wrote...
>>
>> You absolutely do not want to do That! ...
>
> I would say, mostly good advice, although I disagree
> with totally trashing solar. It's really a matter
> of how many solar panels; my house has enough so
> our solar creates more electricity than we consume.
Solar PV is something of a joke in the UK 50N since the sun is only high
enough to be useful for half of the year and half the time it is cloudy.
> But he's right, a set of solar panels on top of a
> trailer or a small cabin cannot be sufficient. My
> brother's cabin in NV has a full roof of panels,
> and deep-discharge batteries, providing plenty,
> but he relies on his generator for heavy-draw
> activities and for topping off his batteries.
turbine. I recall one very early turbine design where the tips vortex
interaction with the supporting pole made it sound like a machine gun in
a strong wind. This was back in the 1970's oil crisis era. Aerodynamics,
permanent magnets and big bearings have come on a long way since then.
--
Regards,
Martin Brown
John Larkin
wrote:
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Phil Hobbs
> On 22/03/2018 13:14, Winfield Hill wrote:
>> amdaws...@gmail.com wrote...
>>>
>>> You absolutely do not want to do That! ...
>>
>> I would say, mostly good advice, although I disagree
>> with totally trashing solar. It's really a matter
>> of how many solar panels; my house has enough so
>> our solar creates more electricity than we consume.
>
> Latitude makes a big difference too.
>
> Solar PV is something of a joke in the UK 50N since the sun is only high
> enough to be useful for half of the year and half the time it is cloudy.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
tabb...@gmail.com
> You absolutely do not want to do That!
> I am currently a lead RV technician at a major dealership in the U.S. I deal with 12V 110V hybrid systems in top end RVs everyday. First, the risk of fire from a current overload is VERY REAL, if you get a dead short on 12V and it is improperly fused, welcome to a glowing hot wire that will burn everything.
etc
etc
Winfield Hill
>On 22/03/2018 13:14, Winfield Hill wrote:
>> amdaws...@gmail.com wrote...
>>>
>>> You absolutely do not want to do That! ...
>>
>> I would say, mostly good advice, although I disagree
>> with totally trashing solar. It's really a matter
>> of how many solar panels; my house has enough so
>> our solar creates more electricity than we consume.
>
> Latitude makes a big difference too.
>
> Solar PV is something of a joke in the UK 50N since
> the sun is only high enough to be useful for half
> of the year and half the time it is cloudy.
and yes clouds are murder.
--
Thanks,
- Win
bloggs.fred...@gmail.com
>
>
> --
> Thanks,
> - Win
bloggs.fred...@gmail.com
bloggs.fred...@gmail.com
bloggs.fred...@gmail.com
John Larkin
Well, if it's your hobby, I suppose it's OK.
--
John Larkin Highland Technology, Inc
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
John Larkin
Winfield Hill
> He's talking about the basic efficiency of the PV conversion,
> which has nothing to do with batteries and inverter technology.
the job done, with enough panels. When using our
HVAC's heat pump, heating the house with solar is
cheaper than burning oil, for temps above 40 deg F.
A roof-full of solar panels is nothing to sneeze at.
We make 11.5 MWh of juice per year, in MA, with a
less-than ideal 45-deg house-angle tilt to the west.
--
Thanks,
- Win
bloggs.fred...@gmail.com
Winfield Hill
> Typical New England oil heat with hot water radiators?
> I ran a search on minisplit geothermal, and, lo and behold,
> there is such a thing. If you ever decide to retrofit, maybe
> when your current system conks out, this would be the technology
> to use. There are no limitations on outdoor temps because the
> heat exchange is with deep soil. The SEERs stay high, both
> heat and cool, hovering at 30, because the indoor-outdoor
> differential temperature is essentially constant. Closed
> system efficiency is exponentially dependent on this parameter
> and it makes a HUGE difference. Here is one I found, there
> are bound to be others.
> http://www.climatemaster.com/residential/tranquilty-split-systems/
> I don't care for their two-stage compressor, that means top
> dollar. There should be a manufacturer out there who knows
> how to use commodity scroll compressor technology (usually),
> about 1/10 the cost, and probably more reliable and long lived.
one for his home. I thought about it, but with all the other
changes, the thought of drilling, etc., scared me off. We're
on the edge of a lake, good underground water for thermal mass.
--
Thanks,
- Win