# Small Solar System, Suggestions Wanted !



## terracore (Feb 6, 2012)

What do you want it to do? On grid or off grid?


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## john457 (Feb 27, 2010)

Off grid. Just a very small system to run about 4 lights and MAYBE eventually a water pump. The cabin will be used twice a week. I don't know what's best for lighting or solar power size. Or even the proper wire size. Dc vs ac I'll use either. Thanks


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## Yoyizit (Jul 11, 2008)

You'll need to know the insolation for your area (it's on the Net), how many cloudy days in a row you can expect (might be hard to find) and max and average power draw while the cabin is on. 

PV panels nowadays may be up to 16% efficient.

This should be a pretty straightforward calculation.


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## terracore (Feb 6, 2012)

I'm looking at doing something very similar. I'll probably go the DC LED route for lighting since it is the most energy efficient and there is no inverter required (you always lose a small % of your power using an inverter).

I see a number of portable DIY kits on amazon that would probably suit your needs. If your usage it typical, you could probably run your water pump (I'm guessing you mean like an RV style) using a single 12v battery hooked up to a smaller panel dedicated for that purpose separate of your lighting needs.


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## john457 (Feb 27, 2010)

There is a good chance I will be going the dc led route as well. I have ordered the bulb holders already to do my at home shed as a small scale version of my real cabin one. Get an idea how bright they are and how many I need. In Canada Costco has some nice kits.


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## terracore (Feb 6, 2012)

mj876 said:


> There is a good chance I will be going the dc led route as well. I have ordered the bulb holders already to do my at home shed as a small scale version of my real cabin one. Get an idea how bright they are and how many I need. In Canada Costco has some nice kits.


what kind of bulb holders, can you show a link?


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## john457 (Feb 27, 2010)

their just the standard MR16/MR11 bulb socket. Their only a few dollars but can be nicely put into pot light cans or other applications. I got them off eBay.


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## john457 (Feb 27, 2010)

My theory is to basically just wire the cabin as if it were a car/rv/boat. I'm thinking about coming from the battery to a boat style panel where you have a couple toggle switches/battery monitor/dc outlet(for the odd small inverter to charge phone/ipod) the toggles are usually fuse protected on the back of panel as well so I would have 1 operating a couple lights outside and 1 operating a couple inside. It works in my head but thats why I'm gonna do the small scale shed first. The boat panel will fit into a 4inchx4inch electical box.

I know the battery(s) needs to be vented so I'm thinking about just mounting it in a box underneath the cabin. Not sure if thats a good or bad idea?


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## terracore (Feb 6, 2012)

mj876 said:


> My theory is to basically just wire the cabin as if it were a car/rv/boat. I'm thinking about coming from the battery to a boat style panel where you have a couple toggle switches/battery monitor/dc outlet(for the odd small inverter to charge phone/ipod) the toggles are usually fuse protected on the back of panel as well so I would have 1 operating a couple lights outside and 1 operating a couple inside. It works in my head but thats why I'm gonna do the small scale shed first. The boat panel will fit into a 4inchx4inch electical box.
> 
> I know the battery(s) needs to be vented so I'm thinking about just mounting it in a box underneath the cabin. Not sure if thats a good or bad idea?


I have the same idea- wire it like any other large 12v application. Mine is going to be small, I was thinking of two 6-volt deep cycle batteries. Don't know about keeping the batteries outside, I guess it depends on the temps you are dealing with. Mine is in Hawaii so temps are not a problem.


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## john457 (Feb 27, 2010)

Another option I seen for the battery is to put it inside in an enclosure and vent it to the outside the same way you would a clothes dryer. this is because some types of batteries give off hydrogen gas.


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## terracore (Feb 6, 2012)

mj876 said:


> Another option I seen for the battery is to put it inside in an enclosure and vent it to the outside the same way you would a clothes dryer. this is because some types of batteries give off hydrogen gas.


You are correct. Of course such gas is only a problem in very confined areas where it can't disperse. I don't know if venting is even a problem in large spaces.


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## terracore (Feb 6, 2012)

MDR123 said:


> Just throwing in a suggestion for something you can run off solar, this site *spam link removed* has led strip lighting and they are 12v.


Amazing that you said that, I was looking at the same thing. (Different place though, cheaper prices). I emailed them to check and see if you CAN hook it directly to a 12v battery without any extra circuit, and you can.


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## john457 (Feb 27, 2010)

The only thing I haven't really been able to grasp with solar is how to connect an ac light circuit to a power inverter. The first thing that comes to mind would be the main feed going to the switch(or light whichever you prefer to bring the feed to) would have an extension cords male end plugged directly into the inverter but that doesn't seem right. With that being said I'm not sure of other options and don't want to spend the few hundred dollars on some thing that's going to do the exact same thing. Any thoughts?


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## terracore (Feb 6, 2012)

mj876 said:


> The only thing I haven't really been able to grasp with solar is how to connect an ac light circuit to a power inverter. The first thing that comes to mind would be the main feed going to the switch(or light whichever you prefer to bring the feed to) would have an extension cords male end plugged directly into the inverter but that doesn't seem right. With that being said I'm not sure of other options and don't want to spend the few hundred dollars on some thing that's going to do the exact same thing. Any thoughts?


I'm not sure that I understand your question correctly but there are a few different types of solar options. The "plug and play" version converts an existing home to solar meaning that everything runs off of AC current including the lights. Such an inverter takes care of your question for you. It's not going to have a "cord" because its hard wired into the house, and usually the grid. 

The small-solar discussion on this thread is more about hooking up a small amount of power some place where there isn't any to begin with. In this case you would want as much stuff to run off of DC as possible so no inverter is required (when you use an inverter, some power is lost in the conversion). Water pumps, lights, etc fall into the DC category and is a typical use with RVs, small cabins etc. Small appliances that require AC power (microwaves, TVs etc) would use the inverter.


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## john457 (Feb 27, 2010)

What I was trying to say is that I don't understand how you get power from an inverter to power household wire. The main feed that would usually go back to a panel in a house would obviously have to go back to the inverter instead but I don't understand how a 14/2 wire or 12/2 depending where your at, hooks up to an inverter? is their usually a spot for it? or would you chop one end off an extension cord plug it into the inverter and just wire the chopped end into an electrical box with your switch?(this would be taking the power from the inverter and feeding your light circuit) This question has to do completely with off grid wiring as there is no panel or anything.

Side note: I do plan on using DC, This AC thing is just something I wanted to figure out. I found some really good articles on homepower.com That really helped me understand the low voltage dc lighting options.


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