A small solar system designed to power lights and possibly your refrigerator for an emergency is easy to build. It is something that you can do yourself without a lot of training.
If you have read this post, you know how to figure out how many panels and batteries you need. You can use either new or used solar panels.
To build your small solar system you will need
- Solar panels — make sure they are matching panels, same size same manufacturer. You can mix some panels but it takes a bit of expertise to get this right.
- Controller — make sure the controller you get will handle the voltage put out by your panels and it needs to protect your batteries by keeping them from being overcharged. Not all controllers do this.
- Inverter — your inverter needs to be big enough to handle the draw you intend to place on it.
- Storage batteries — get good quality deep cycle batteries.
- Miscellaneous wiring — make sure the wiring will handle the current draw.
Get good quality components; go to a good reputable supplier like sierrasolar.com. They are a good source of reliable information.
Now that you have all the parts, it is fairly simple to put it together, assuming you have some minimal electrical skills.
Here you can see the wiring on a solar wagon. This shows the batteries and the inverter.
Once you have your panels, determine where you want to place them. They need good sun exposure for as many hours as possible. One option that I have seen is to build a solar wagon, An Easy to Make Solar Wagon. You can build a unit that is portable and you can move to make the best use of the sun. A wagon can carry enough panels to supply lights and run a refrigerator.
With a small solar system, it is best to connect the panels in series. This means you attach the positive leads to the negative leads. Two 12-volt panels will produce 24 volts. So for each panel, you add your voltage increases. This is different from a large system where you may have strings of panels in series and the strings then connected in parallel.
Next, attach the leads from the solar panels to the controller. Then run your wires from the solar panels to the batteries. The batteries should be wired in parallel. Your jumpers between the batteries and to the inverter should be out of 2 AWG cable for up to 100 amps. For 200 amps you should use 3/0 copper.
This shows the panels connected in series, the controller and the batteries
This is how you wire your batteries in parallel
The inverter should be connected to the batteries. In mine, I would put a box with at least two 15-amp breakers between the inverter and the appliances. This is not mandatory but is a good safety feature.
There are several ways to build these small solar systems, some are more complicated than others. This one is about as simple as you can make. Have fun.
