# solar power question



## Dixie Bee Acres (Jul 22, 2013)

Not that I will be able to do this anytime soon, but I have an idea about an off grid solar power system.
When ever I can build my system, I am thinking of rewiring everything in my home to 12v DC. I would likely need an inverter to run such things as my well pump and refrigerator, I know those can be aquired in 12vdc, but for now let's just assume I need an inverter for those.
Other than that, 12vdc lights, ceiling fans, even TVs and radios can be found reasonably. And I don't see it being too complicated to convert a woodstove blower to a dc motor.
I guess a washing machine might need to be on an inverter as well.

Now the question, other than the hassle and costs of redoing the existing wiring in a house, is there any practical reasons for not running a system on 12vDC?


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## Twobottom (Sep 29, 2013)

I think its mostly a matter of cost. It might cost you more to get all new appliances then what you will save. In a cost benefit analysis, most people find it easier and cheaper to just go with an inverter.

I think I've also read something about DC being more volatile.


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## Gray Wolf (Jan 25, 2013)

12 volt DC requires much larger wire and different wall switches than AC. The length of each run needs to be considered to be sure the wire is large enough. Bulbs cost more. Appliances cost more. Outlets need to be different than AC outlets. It will cost you more than just running stuff from the inverter you will have anyway. I wouldn't do it.


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## TnAndy (Sep 15, 2005)

No, I wouldn't either. You'll find is it simply cost prohibitive to do this in an existing house.

Only way I'd consider it is IF I were building new, and a very small house. Even then, I'd probably dual wire for 12vDC and 120vAC as well.


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## Dixie Bee Acres (Jul 22, 2013)

Thanks for the replies.
Andy, you bring up an interesting point, one which lead me to ask the question in the first place, small cabin.
If I can build a small get away type cabin, say 2 rooms, 260sqft or so, I would wire it completely in 12 vdc. Thinking a handful of lights, couple ceiling fans, and a couple outlets for other items.

Oh, and yes, longer runs do require heavier wire, learned all about that when I use to build and install high output audio and video systems in cars. You get a lot more boom out of your amps running two runs of 00 gauge power wire rather than a single run of 4 gauge, but you also have to closely match that gauge with ground wires as well.


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## AVanarts (Jan 2, 2011)

TnAndy said:


> No, I wouldn't either. You'll find is it simply cost prohibitive to do this in an existing house.
> 
> Only way I'd consider it is IF I were building new, and a very small house. Even then, I'd probably dual wire for 12vDC and 120vAC as well.


 That sounds like what we are doing. Our new place is wired with 120 VAC for conventional stuff with 12 volt DC for a backup lighting system using LED's. We also have a 24 volt circuit wired in for our Sundanzer refrigerator and freezer.

Our inverter runs off of a 24 volt source so we use that for the fridge and freezer and we have a smaller 12 volt system that runs the LED lights. At first I assumed (WRONG) that I could wire pairs of 12 volt LED's in series and run them at 24 volts. Unfortunately, it doesn't work that way and they get waaaaay too hot, sometimes even flying apart at 24 volts, even in series.

These are the LED's that we are using. We use one warm white and one bright white in each pair to get a better coverage of the spectrum.

http://www.ebay.com/itm/310642018100?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

http://www.ebay.com/itm/350805504078?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

http://www.ebay.com/itm/300721803753?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT


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## Cyngbaeld (May 20, 2004)

I plan to run ac from the inverter but will also have some dc outlets. I already have the few dc items I want to run, fans, and pumps mostly. If you are going to run some dc lines, think about putting those items close to the battery bank.


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## 12vman (Feb 17, 2004)

I wired my place (Rebuilt 12'X50' Mobile Home) by running a power buss along the ceiling from end to end and tapped from it where ever I needed power.. 

The buss was the most expensive part. (2Ga. welding cable) That is plenty big enough to handle any loads that I ever planned to connect to it. Any large loads (Pump, Inverter, ect..) are connected near/from the battery and wired accordingly. (Separate circuits)

I avoided wire line loss to lights on the ceiling by installing small relays at each fixture and controlling the relay via standard telephone wire and standard wall switches. Run the power directly to the fixture instead of through the wall switch. Makes the runs much shorter and cheaper. I've controlled relays this way over 50' in distance..

Wiring a small cabin in 12 V.D.C. is easy but to wire a whole, existing house would be a chore. Also, 12 v.d.c. wouldn't be my choice if I were to run anything large on 120 v.a.c. 24 or 48 volts would be more efficient, especially for a fridge or a well pump. (Hi-Demand items) I run a 400 watt inverter to operate a hot glue gun or my soldering iron, or to _easily_ charge my power hand tool batteries and that's about it..

I have a washing machine but I operate it with a generator. My fridges use propane. I move water around with 12 volt RV pumps..


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