Help me build new Solar System

Time to replace my aging solar system on the cabin. And I'm no electrician by any means. It's all black magic to me. The system I have now has two 60 watt ( I think ) panels, tiny charge controller, 4 batteries and a 1000 watt inverter. Which is about the only thing I use to charge my device batteries. There are a few 12vdc outlets and some lighting. Which I rarely use at all. There is a 12vdc tv which I watch about 2 hours a month and I need to occasionally run a mini shop vac which is a 60hz 120v 6amp deal. It takes me about five minutes to vacuum the place once or twice a month. So the load will be light, I think. I want to replace everything and need to install it myself due to my location. Or maybe I'll fly someone out to install for me. I want quality components and batteries. Build it for me because I have no clue!

 

Here's what I have now. Notice the batteries were manufactured in 2004....but are still working. How well is another story.

 

The panels face exactly 180 degrees due south. Don't know how I'd go about changing the angle to use all the summer sun. Winter they are perfect where they are at. Can you list components I should buy? Amazon links maybe?

 

And I'd like some kind of panel that can tell a novice how well the system is working rather than just the voltage currently.

 

And my panels can't be any larger than 30"x26".

 

MM, ever think about adding a small (400w or so) wind turbine to the mix? Looks like it might be breezy enough to gen some power when the sun ain't shining.

 

One can pick up a 400 watt turbine for about 1.00 / watt or less

 

If you relocate batteries outside, you should use an MPPT charge controller (as BT first suggested) but with temperature sensing. Should probably have a temperature sensing charge controller anyway. Your batteries will thank you with longer service life.

You may want to consider monocrystalline solar panels as opposed to polycrystalline. They do a little better efficiency wise, which means they'll charge a bit better in low light conditions. I bought some for my BOL about two years ago for .85 / watt (shop around). I kicked myself. This particular model has been sold out ever since and I should have bought ten panels instead of six.

At .90 / watt, a couple of these 270 watt jobs may do you up pretty well - Hyundai 270w solar panel, solar module 270w
Click on "home" will allow you to navigate through their other choices. This is where I bought mine, but there are lots of choices and lots of places that sell them.

If size is a limiting factor where these are located, I'd move them. Mounted mine on the ground on racks that I built myself out of angle iron. I'd also move those batteries, or at least ventilate that compartment. They generate hydrogen gas while they're charging and all you need is a tiny spark.

Even in the desert SW, where the sun is plentiful and strong, there are days with heavy overcast conditions - especially during monsoons, which is why I went the monocrystalline route.

 

Thanks for the advice, and I just realized that I hadn't thought of that. I'm not in Alaska, but what happens if my batteries get low and it's below freezing? Are there any kind(s) of cells that can be both discharged and frozen without damage?

William Warren

 

Good question - Nickel Cadmium, Nickle Iron, maybe some of the newer lithium types?

If lead acid are discharged, which means the electrolyte is near water, they will be destroyed if they freeze. Never been a concern as I keep mine in insulated boxes, and it never stays below freezing for more than 8 or 10 hours or so in the dead of winter, and that's unusual.

Also, you greatly shorten the life of your batteries when you discharge them that far. So perhaps if your batteries are becoming discharged enough to freeze, you should be looking into the issue of why that's the case.

But then I have little experience in dealing with extreme cold. Even up north places like Michigan, Montana, N Dakota to name a few, can probably hit -30, -40. I lived for a time in northesten Nevada, where it hit -10 to -20 and that was enough.

 

I would like to move the batteries outside if possible. What batteries withstand extreme cold the best?

 

There are experts on here with those answers (I'm not one of them). But what I do know, is Batteries too cold will not work, and too hot cook off.
I know your cabin is on a bloody big rock, so the first answer would be wrong, (plant them under the cabin) so we need to go to plan B. You need to dig a hole @6' deep (minimum)(in the dirt) and insulate the walls well, but not the floor of the hole. (Iirc) there is a year round 56° @ 6' down. It will also need an insulated plug or hatch for the top of the hole.
It is the only passive method I know of that would work for hot and cold weather.
A hot box would keep them warm, but could overheat, if not monitored.

 

My $.02.
Y'all seen the roofing tiles that are photo-can't-remember-the-rest? Seen some that look like Roman/Spanish Tile, and some others.

 

I think I will be putting a solar panel on the side of my home like @MountainMariner. I am not confident in putting a panel on the roof and do to this will be a learning experience, I think placing a panel that is accessible would be a safer move. I have watched the sun for the last month and have the perfect spot on the house for a panel. The place I would put the panel has easy access for wiring into the house (batteries). I know some will say it is a waste to do one but I do not want to go whole hog until I know pros/cons, issues and if it is feasible.

 

I agree that many of us want to "test" and feel comfortable with new things. Sounds like a plan.
Go for it!

 

If nothing else, you will always have a back up phone charger, or battery charger.