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November 3, 2011 at 3:37 pm #36933
This is just a repost from another thread i thought it would make a good discussion.
what gordo said about battery voltage is correct put simply the higher the voltage means you need less current to do the same amount of work which means
less power loss in your wiring.when you go with lower voltage you will need
to use larger wiring (which is more costly) there are wire size calculators around places when the time gets close to you buying gear. but for your little home I would very much recomend 12 volt unless there is a very good reason to use otherwise like for example your wind turbine or solar panel are situated on a hill a long distance from where your battery bank and home will be.
before I go to far just want to tell you I dont like high voltage AC power
for many reasons health is one, radiation affecting low power radio signal
is another (i dont like CFL light bulbs either for same reasons)I use it when I need to but when I dont I shut down my inverters and run of low voltage DC this is also more efficient use of power.basically AC produces RF radiation
which is bad i dont care what anyone else says about its safety
Im going to stick with 12 volt even after i have built my earthship and the reasons are these, price,availability and compatability
price for 12 volt gear is much cheaper than other gear that runs
of higher voltage DC simply because 12 volt gear is used in so many different
circumstances 48 volt for example is very specialised in its uses.
Availability almost anything you could ever want as an appliance you can get in
12 volt some i would not recomend using due to there high power needs like
toasters, micrcowaves coffee makers etc
all your bigbox stores like wallmart,target,harbor freight etc sell 12 volt gear as often as camp gear but somtimes they dont even realise the compatability to a off grid purpose look at the back of portable tvs and stereos if they have 12v inputs or battery slots that add to 12 you can run them of your home power.cordless battery operated power tools can almost always
be run directly from 12 volt as well (wired in without the battery) 9.6-18 volt
Autopart stores,truck stops,hardware stores,rv supply stores,junk yards
or junk cars,flea markets,camping outfitters,marine supply etc they all supply 12 volt gear.
Compatability i already mentioned some instances of compatability like the
stereo and power tools but if your doing this on a budget you may start
hitting garage sales and flea markets for all sorts of bits to build your
dream home often you will find inverters, batteries, solar panels and most will be 12 volt.if you pick up say a solar panel on the cheap you can add
it straight into your 12 volt system but if you have a 48 volt system you
will need 4 solar panels the same before they are usable.
try this experiment hit the garage sales and or fleamarket for the day
and keep track of how much gear you could pick up if you had a 12 volt system
as opposed to a 48 vlt system.
Another thought i had was reliability most of those big 48 volt systems
actually run most everything of the inverter so 110 V ac or 220 Vac I wont pretend to know what percentage of people that run a duel power system for example if the inverter ever gives out for whatever reason then the home is
still fully or almost fully functional lights,fridge,water etc
im guessing the percentage is a smaller one because it requires a lot of extra wiring and some expensive gear.
if my 12 volt inverter ever gives out oh well I can afford multiple backups
and I could pick up a new one from any truck stop and untill then i still
have all my necessary home apliances.November 3, 2011 at 4:51 pm #41919
chowan- all really good points. in reguards to the other discusion. if laundry and washing comforters is a priority her project won’t be a dyi.
i just upgraded from my old car batteries in a cooler with a die hard 750 inverter. when i did i removed the transfer switch from the generator. in hind site if i do have a gear problem im in the poops for h20. there is also a catalog company called all vans ? something vans the sell stuff to equip vans and trucks for contractors. some good deals on inverters. one caution on 12v systems. not sine wave. watch your recharable tools and computers. ipods and pda stuff are all ready 12v/120.
i built a 12v systm that i pluged into the trailer lighting harness used to charge while driving(had to commute 45mi each way daily. thats what i used before i even got my first 15w pannel..
good points chowan- nice to hear other perspectives.
gordoNovember 3, 2011 at 6:37 pm #41921
yep i did something similar with my trailer.
This is what i used to get set up ut here before i had my solar
and wind set up.
in regards to washing machines depending on the size of course many can be run from even cheap non sine inverters ive been doing that for years but they
do suck the stuffing out of battery banks.a better choice i think is to run a backup generator wash day and top up batteries at the same time.
its also possible with some older simpler washing machines to convert over to
12 volts if you ever wanted to but it will still be an energy hog.
another idea i had and pursued it a little way was using my big wind turbine
as a direct mechanical power source which would be able to drive a washing machine and other tools in good wind conditions
This is what I want to get re setup in this area.
basically i want a big multipurpose wind engine that when not used for other
purposes can be charging batteries as well.
possibly used as part of a village/community resourceNovember 3, 2011 at 7:51 pm #41922
also with modern LED lighting much of the load that would have been placed
on a 12 volt system through lighting can be cut down so in theory you would not need as much heavy duty cable as used to be necesary for a 12 volt system.November 7, 2011 at 1:17 am #41930
I’ve used Cat5 cable (24awg) for powering LED lighting. It only costs pennies per foot, and since there are 8 wires total, you can run 4 dedicated circuits on each cable (or you can run 6 circuits and share 2 wires as a return path). Depending on how many LEDs each light contains, you might only be able to have 1 per circuit anyway, .
Using direct mechanical power from a wind mill is a great idea. I’ve been collecting old shop tools that are belt driven with the intent of hooking them up to such a ‘mechanical power-source’. Tools like: air compressor, bench grinder, drill press, band saw, table saw. Do you image your wind mill could produce enough mechanical power for these?November 7, 2011 at 2:08 pm #41932
yep most of those would run of my big turbine but the band saw and table saw
would likely need more blades and higher winds.
aproximate power to the tool under experimantation would be about 1 hp in 15 MPH winds and up to about 4 hp in 28 MPH winds.
here is a good read about wind turbines there is a chart on the page
which lists wind turbine diameter wind speed and power output of a fairly efficient turbine
the power outputs are in watts just divide by 746 to get horsepower
my turbine was not as efficient as what is in this list but the next time
i set it up i have some improvements to make like getting rid of that rope
drive which had a lot of slip in it and modifying the differential to cut down on friction.
if mechanical power was the main use then more wider blades would be the best choice as that will give much better torque for electrical generation thiner
faster spinning blades are a better choiceNovember 24, 2011 at 8:26 pm #41982
Going through all of our stuff and selling off what we are not bringing West has forced me to think about this.
There is NO QUESTION that with regular auto wiring, (heck, speaker wire at 12 ga even) will work fine for LED lights running on 12 volts. The biggest error I see people doing all the time is thinking that thicker is better.
One thing to remember is the more strands, the better. A huge 120v wire for a home that would work great for triple phase 440 will not work as good as 12 gauge speaker wire for 12 volt DC. (I encourage you to check on this with an actual scientist, not a prepper you know who THINKS he or she knows.)
I have done the homework on this and I have to agree with Chowan. The way I intend to wore my earthship is to have white switches and black switches in the wall. Everything white will be 12 volt and powered all the time.
The black circuits will only be generator powered…like the big screen TV, the washing machine, My home audio amplifiers…etc.
If you look at the wire load balance, you can use very small wire if you wire it more like a car. Running 4guage to the main distribution block with about 6 batteries, keeping the system 12 volt allows you a HUGE power draw into the home for about 30 bucks. You keep the high-draw items close to the 4guage.
For example, running a single 4 gauge line into the bedroom would not be needed for an LCD TV and a regular shortwave/alarm radio.
I have seen people elsewhere on the net say doing things this way is unsafe, but if you use fuses and keep them well under the load ability of the wire, you will never generate any heat at all.
For us, keeping it all 12volt is a no brainer…as long as I can fire off the genset every third or fourth day for an hour or two.
My Linn LP12 is a MUST for me as is the rest of my hi-fi. But using a car amp and the CD player for daily use brings the power needs down to near zero.
When I want to play vinyl and really sit down to listen, I can fire one of the gennies and do laundry as the vinyl spins and I make a ton of heat with the class A amps. A couple of diodes and switches will make this a painless operation.
I have to say, the idea of using 120v stuff off grid just does not make any sense to me. If you are running on batteries, you are trying to be very frugal anyway…so the power needs are minimal.
In fact, as a joke, I have run 5 of the harbor freight LED mini flashlights in a room with diffusers on them.
I encourage you all to give it a shot. if placed in a plastic wiring box and daisy chained, you can have wonderful lighting in a 15X20 room from 5 of these units, at a total cost of about 17 bucks including everything…less than the cost of one good 120v LED light bulb.
(We used the frosted light covers normally used in ceiling fans and while I would not read with it unless I went for 6 and aimed one on my page, for every other function, it was great!)
I would really like to see anyones ideas for 12volt stuff in the home.
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