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TheLoringLank
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# Posted: 9 Jul 2009 19:40
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Hey there,
Stumbled on your site while "simple solar cabin". My wife and I have just built a small (600 sq. ft.) cabin off-grid in a town called Loring, ON. We were planning on going solar for our very limited electrical needs. Our desire was to install a simple solar panel (50W or less) and a deep cycle battery and wire our cabin for 12V.
We would simply be running a few 12V lights and possibly wire in a few 12V receptacles to plug in a small 100-200W inverter to power a laptop computer or other low wattage devices. Our fridge is propane and all our cooking would be propane as well. We don't watch TV, and if we need to power tools we just borrow a generator from a friendly neighbour.
I don't want to go AC, since we want to keep things simple I would love to stay completely DC.
A few questions:
- what gauge wiring should I be using to wire in a few outlets (furthest being 30 feet from the power source) - I know that wiring for DC is funky with voltage drops and amperage loads - I don't want to overheat my wiring.
- where do I find DC circuit breakers?
Has anyone else done this that could give me some hints/tips?
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soundandfurycabin
Member
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# Posted: 10 Jul 2009 00:48
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For the circuit breakers, I think the Square D QO series of AC breakers are also rated for up to 48V DC.
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Vince P
Member
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# Posted: 12 Jul 2009 10:06 - Edited by: Vince P
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Quoting: TheLoringLank I don't want to go AC, since we want to keep things simple I would love to stay completely DC.
This is very difficult. Not only does this limit the types of things you can plug in, your wiring length must be very limited due to DC power loss. Better to run lines for AC and lines for DC.
My own solar wiring marathon went like this:
1. Decided on inverter AC exclusively, because with 3 kids, I wanted to keep them happy with charging their games, music players, etc.
2. A couple years in, my batteries (3 deep cycle), took forever to charge, so I decided to convert to DC and keep the inverter plugged in one DC outlet for occassional AC need. I had to buy Compact Flourescent DC lighting (expensive) via ebay and backwoods solar.
3. Found out after converting to DC that the bigger CF lamps required a minimum of 10 guage wire! Went back to inverter AC exclusively.
4. Found some of my solar panels, not functional, but still under warrantee. Replaced no problem.
5. Need to reassess how to keep my batteries charged. Either take out some trees that are shading the panels, or buy a top quality battery charger to run off the generator, as cheap chargers don't seem to work well with generator power.
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lamar5292
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# Posted: 26 Sep 2009 02:09 - Edited by: lamar5292
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I use 10 gauge stereo wire for dc wire runs but you could use heavier.
The secret to not overloading your wires is to not have to many dc gadgets running at once.
I use direct dc for lights only and use rv style dc lights which use very little power.
Tvs, laptops etc will run better off an inverter and I use a 400 watt to handle laptop and tv at same time.
RV supply stores have fused bus bars for running your dc wires to. These accept auto fuses and a 20 amp fuse is what I use
LaMar
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Moontreeranch
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# Posted: 3 Oct 2009 12:20
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I modified some 50 watt Halogen lights to run on 12 V DC LED'S I have not installed them yet as the cabin is still in construction mode, but my light plan went from 700 wat to less than 40 for the entire cabin. I plan on using 12ga for running the lights...each light is 1.8 watts and puts out about 80% of the light the 50 watt halogen does.
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treeangel
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# Posted: 18 Nov 2009 16:17
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when we began cabin living 25 yrs ago my brother-in-law gave me the best advice ever--he had been living that way for years. he said to put 12v, 110, and propane for lights in every room. redundancy is great. i have lived with my cabin that way now for 20 years, and although the world has changed now and most people have opted for inverters and 110 exclusively, i find that my way is the best--the most efficient, and my inverter is a trace 612--20 yrs old and still ticking! this is because it only gets used when needed, and is off a lot of the time. i wired all the 12v with 8 gauge wire, not so easy to work with, but it has very little voltage loss in our small 2-story cabin. the propane lights can be left on all evening--no worry about having to limit their use, and they add heat, which is very helpful on cloudy and marginally cold days and nights to avoid having to crank up the wood stove. hope this is helpful to you.
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treeangel
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# Posted: 18 Nov 2009 16:19
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Quoting: TheLoringLank I don't want to go AC, since we want to keep things simple I would love to stay completely DC.
my post at 16:17 today was in answer to this quote. sorry, just learning the setup here.
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hbarker1
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# Posted: 28 Jan 2010 22:35
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propane lights ,, where you get those at treeangel?
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lawnjocky
Member
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# Posted: 5 Feb 2010 18:00
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West Marine carries a lot of 12v stuff. Also there are a bunch of books on wiring boats.
Jocko
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rayyy
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# Posted: 26 Jan 2011 16:16
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I was thinking the samething Treeangle.To wire up for both 12v and 120v and propane lights.I want to be the state of the art green,off the grid living,but to prove that you can be just as comfortable without storebought electricity.I'll make my own when I need it.There is a solution for every problem.Don't relie on just one or two but all three.
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larryh
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# Posted: 26 Jan 2011 16:21
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I used #6 copper which was the Home Power magazine recommendation for what they called a Bus system where you run the length of the house with the # 6 and then tie in with lighter wire to your receptacles. My wire runs about the length your suggesting with out any issues in power drop.
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timber
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# Posted: 29 Apr 2012 10:11
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I find myself debating the idea of running 110 or 12 volt, I have had a reply from folks saying ,run 110 and use an inverter.maybe running both isnt such a bad idea, could use the inverter for lap top and tv. 12 volt for lighting only, i like the idea of running propane lamps for the light and heat ,my cabin is only 256 sq ft with 64 sq ft loft.
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sparky1
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# Posted: 29 Apr 2012 12:05
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Propane Lights (could) if burned enough create to much carbon Monoxide-might make you sick-it the cabin is pretty much Air tight. My first Travel Trailer had one---I got pretty sick because i didn't have a window lightly Cracked for fresh air.
sparky1.
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TomChum
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# Posted: 29 Apr 2012 12:17
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Quoting: larryh Bus system where you run the length of the house with the # 6 and then tie in with lighter wire to your receptacles.
I like this. I could run a #6 bus on each side of the cabin then I'm set. Thanks!
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razmichael
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# Posted: 29 Apr 2012 13:41
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Not sure the details on the bus mentioned from the magazine but it may be the same or similar to wiring a ring main - very popular technique in the UK. Here is one link I found (not likely the best) Ring main that explains the technique. Making a ring just reduces the distance the current needs to flow as it can "travel" in either direction. It should, if done right, reduce the need somewhat for thicker wire if properly planned. I can't see why it could not work for DC assuming it met the needs of the cabin. Having said that I have never tried it with DC.
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arbaleste
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# Posted: 29 Apr 2013 23:57
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I wired my cottage on Ruxton Island, B.C., all plugs were wired to panel and inverter and the lights wired 12 volt,10 gauge throughout to fused panel, for the lights,used track lighting, wired the bar 12 volt, took the guts out of the MR16 lighting fixture{110 to 12v} and adapted, works great
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jjlrrw
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# Posted: 30 Apr 2013 12:37
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I would look into gas lights, lights will be your biggest current draw. Would even consider and Honda 1000i generator in place of the solar panels. The Honda will change your battery much faster and you won't need to add a converter to change electronics. Plus the generator is handy for other applications and will pack nicely in a car or truck.
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Truecabin
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# Posted: 30 Apr 2013 16:38
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crazy to pipe for propane when 12volt LED lights use so little power. why bother with propane or gasoline for your lights. solar panels last 25 years and you dont have to change the spark plugs or oil and you can hear the animals. propane lights have constant hissing too and you cant just flip a switch you have to light it.
If your wires are too small for 12v then your light is just dim its not a safety problem. if the light is bright enough then the wire is big enough. If you are usung LEDs the wires can be very small you have a hard time finding a wire too small for LED. regular romex house wires are oversized for LED dont worry about it. a lot of people are afraid of solar because they don't know the systems but its a good system you just have to learn it. you can run a lot of LED lights just from a car battery that you charge at home or idling your car for 30 minutes or bring it home to re-charge.
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Just
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# Posted: 30 Apr 2013 17:13
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This thread was started almost 4 years ago ,,the world has changed .AGAIN !
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rayyy
Member
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# Posted: 7 May 2013 13:14 - Edited by: rayyy
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Yes it has,just.I wound up running all 12 thhn Black and red to all my 12 volt light fixtures and outlets in my cabin.The longest run,maybe 40 feet.All in armored cable or conduit.With each light fixture drawing no more than 13 watts,I'm safe using 12 guage.Look at a semi trailer with lights 60 feet from the cab of the truck all ran in 18 guage wire.I also have several 12 volt ciggerate lighter style outlets throughout my cabin.So far so good.Never had any problem with any of them.
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ICC
Member
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# Posted: 7 May 2013 19:09
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not that it matters much as it seems most everyone here doesn't bother with or have the need to work to code or have an electrical inspection, but there is a convention used by the inspectors i have worked with when it comes to wire colors in DC circuits.
the motor vehicle convention of red is positive and black is negative falls afoul of the NEC. the US National Electrical Code (for both AC and DC) mandates that the grounded neutral conductor of a power system be white or grey. that means what we call negative in a DC system should be white or gray and never black as that is reserved for hot wires.
the protective ground must be bare, green or green-yellow striped.
hot (active) wires may be any other colors except these. however, common practice (per local electrical inspectors) is for the first hot (live or active) wire to be black and the second hot to be red.
using black as hot and white as negative makes it simple to use regular off the shelf romex (NM) wires for DC circuits.
in the UK and europe they go in a different direction. DC circuits in a bldg use brown and blue. easy to tell the DC from the AC there.
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Borrego
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# Posted: 7 May 2013 22:41
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Although I am still learning, I gotta ask; why use 12v at all? It seems too easy to use an inverter and go with 110v.mI must be missing something........
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ICC
Member
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# Posted: 7 May 2013 23:37
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Quoting: Borrego why use 12v at all?
different people, different ideas. i'm solidly in the camp that advocates the use of 120 vac from a good quality inverter, pure sine wave. but i also have a few 12 volt lights wired in, under kitchen cabinets and bathroom and porch. why? because IF the inverter craps out i will still have some lights that will work. i also use a 12 vdc shurflo water pump and have a couple of 12 vdc transfer pumps. those pumps are also available in 120 vac but not as readily available. my 12 vdc comes from a power converter that is connected to the battery bank which is 24 vdc; better than tapping into the string of 6 v batteries.
i believe some people believe the inverter wastes too much power. true there is some loss but a quality inverter also has a sleep or suspend mode. it shuts down and waits for a demand and then kicks in. the wait is almost not discernible. the trigger point is programmable on a good inverter. mine will kick in when a small led night light is turned on. so most of the day the inverter is waiting and only using milliamps.
my opinion is that there is a greater array of appliances in 120 vac, more variety and more choice of quality. i also don't believe in cutting the system size so fine that i have to worry about every watt that gets used. the system is supposed to work for me and not the other way around. imo.
also imo 24 vdc systems make more sense than 12 vdc, unless the system is very small like only a couple of golf cart batteries.
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Borrego
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# Posted: 8 May 2013 14:08
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Quoting: ICC why? because IF the inverter craps out i will still have some lights that will work.
Ah, I see. Makes sense.. I will add a couple of 12v items to my plans. Thanks for the explanation ICC. Otherwise, I can see little reason to use 12v. I wired my cabin as I would wire a typical house and will be doing the system next fall...
great posts by all regarding solar, I am learning sooo much.
BTW, ICC, one of my distant neighbors out in the desert uses a 48v system. Is that really necessary? Or in your view, is it worth doing/
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Dillio187
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# Posted: 8 May 2013 14:53
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48V systems are great because you can series wire 8 6V batteries into a single bank, which enables them to charge and discharge evenly, use smaller cabling, and yet provide a lot of power.
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ICC
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# Posted: 8 May 2013 16:03
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ditto that more or less. if the battery capacity is large enough 48 vdc can be an advantage. also if inverter loads are large enough a 48 vdc system can have advantages.
a disadvantage to 48 vdc is that is very close to being a lethal level for some people, not so with 24 vdc.
the ideal is to have a single series string of batteries or even cells. there are many sizes of batteries available. using a single series string of larger batteries is better than two or more series strings on smaller batteries in parallel. larger do cost more though per amp-hour when we compare to the good old cheap golf cart battery.
i made my new system with a string of 12 - 2 volt Rolls Surette wet cells.
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David
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# Posted: 2 Jul 2013 19:40
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hope this might help with voltage drop. I 'am a electrician and work with 12 volt lights all the time. when we dont want to run heavy gage wire we will run it parallel basically that means if you needed #8 wire and you had # 12 wire you can run 2 sets of 12 wire to make up the gauge and always use stranded wire it keeps your voltage up
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Truecabin
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# Posted: 3 Jul 2013 11:51
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Quoting: Borrego I gotta ask; why use 12v at all?
junk inverters are junk they can drain and ruin your batteries and a good inverter is expensive and is one more thing to be stolen from a vacation cabin
and 12v is easy for a cabin but i can understand 120 if yours is a house
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rayyy
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# Posted: 3 Jul 2013 17:15
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So here it is,7-2013 and I'm still very happy with my set up.Ask yourself,what do you want to be able to power up 24 hours a day,7day's a week without a generator?That's what I put on 12 volt.I want lights,cellphone charging and flowing water.They are all 12 volt.When I need 120 volt ac,I fire up my genny for computer,printer,fan,sterio,t.v.,microwave,vaccuum cleaner,washer/dryer,hair dryer(michelle)toaster,dvd/vcr,electric tools,,,that's about it for my 120 volt needs.
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dmck
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# Posted: 7 Sep 2016 12:14
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Like the gentleman above, I wired my cabin with both 12 and 120. Why? If you have problems with your inverter, you still have power. And with a small system, the 12v appliances are way more efficient and there are plenty of options these days. I run all my permanent appliances on 12v and still have the option of running regular appliances with the 120. It only took a few extra hours to wire and I am very happy I did.
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