Using your Solar Panel Power
When you first consider using solar panels to make your own electricity, there are so many questions before you make the decision to either buy an expensive off the shelf system, or build your own. Commercial systems can cost several hundred or even thousands of dollars.
You may also have read that you can build a solar panel for about $200 - so what's going on here!
Before you even consider solar power, even if its just supplemently your needs on your hobby farm, you need to think about how you will be using the power. If you're in town, how will you hook the array into your house, do you need permits and whether it will be tied to the grid or not. On the farm or on your block in the coutry, it's easier. You may simply need some lighting, maybe run a pump or just be able to listen to a little music wafting through the trees. In any case, with an "off-grid" situation, you can be a little more flexible. Whatever the location, how much power you need, how many arrays and how long will your power last should be the questions to ask.
Most DIY solar panels are based on a set of 36 (3 amp, 3x6inch cells). The size of a array like this is roughly 1 x 1.5 meters. Your actual array size will be up to you. However, a single array like this will normally produce 18V at almost 60Watts in bright sunlight.
How much power is this?
Lets keep this simple, here's the potential for our 60Watt, 18V example array. If you had a 60Watt panel and could get 7 hours of light a day, 7 days a week, you would produce 2940Watt hours per week, all of this is being very optimistic.
Realistically, you might get 4 to 5 hours of good sunlight, producing about 2100Watt hours (60Watts * 5 hours * 7 days). You will of also of course have a few cloudy or rainy days, with reduced power(maybe half).
What can you run with that power?
1 x 10 watt compact fluorescent lamp (CFL) for about 2100 hours (or)
10 x 10 watt CFL(s) = 21 hours, about 4 hours per night for 5 days (or)
1 x 50 watt Laptop = 42 hours, about 6 hours a day for 7 days (or)
1 x 75 watt TV = 28 hours, about 5 hours a day for 7 days
(This assumes you are discharging your batteries, which you should never do)
To give yourself some leeway, you would probably build 2 arrays, making it a 120Watt system and add extra batteries. So, now I think you can see the potential of what a small inexpensive DIY solar system can do.