If you ever want the sun to stop shining, build a solar panel. Its been 4 days since I built my half panel and the best sun I’ve had was behind thin clouds.
Today was different, though. 17 degrees and the clearest day I’ve seen in a long while. Perfect for testing the peak output on my panel. In spite of two cells having defects, it was able to put out the full 6 amps the cells were rated at. It also managed to put out a tad over 10 volts, putting the peak power at a little over 60 watts!
This means at best my system will put out 120 watts of electricity under full sun and produce heat for air or water.
Why have I stayed away from solar for so long? Let’s look at it this way. Assume the full panel can put out 100W for 8 hours a day. This amounts to .8kWh output per day. My electric company charges me 8.5 cents per kWh, so my solar panel would save me about 7 cents a day when there is good sunshine.
The full panel will cost me $40 to build. This means it will take at least 1.6 years to pay for itself. With the variable nature of the weather, it will be more like 2.5 years. This does not take into account batteries, charge controllers, etc.
By using the excess energy to heat air or water, you can shorten the payoff. By how much is what I am trying to establish.
I’m taking a slightly different route with solar energy than is commonly taken. Given the fairly low efficiency of solar cells (under 20%), why not harvest the remaining energy as heat? This can be used to supplement heating a home or heating water. I’m going to start this project by trying to produce electricity and adding additional heat to my house since it is near winter.
Here’s the panel I am building:
This panel is made of a 4×4 grid of 6″ solar cells, each rated at 3.3W. With ideal conditions, it should produce 52W. With this morning’s less than ideal conditions, I observed 37W. Two of these panels will be necessary to charge 12V batteries. I’ve been working on using lithium ion cells for at least part of my off grid energy system.
I mounted the cells between two 26″x27″ windows from an old mobile home. I used silicone adhesive to seal the two together and keep the weather out of the cells. This will create a double glazed solar heater when added to a wooden heater box.
I still have to build the other panel and construct the heater. Hopefully this will add a bit of heat to my home when the sun is shining. Cold weather and work has hindered my rocket stove video production, so I am way behind on that project. As weather and work permits, I’ll keep plugging away on the video.
Again, like any natural power source, we are looking at less than ideal conditions for producing power. In spite of that, I have managed to charge a 9Ah battery, a USB rechargeable razor, and run a PC fan all at the same time in the late afternoon sun. Here is the panel in action:
From this demonstration, I hope you can see that even a small solar panel can be useful. Just because you can’t afford a huge solar panel array, deep cycle battery bank, and state of the art mppt controller doesn’t mean you can’t build a smaller, simpler system for camping or emergencies.
Today is a pretty nasty overcast day – perfect for testing my solar panel in less than favorable conditions. I got 16.53 volts and .06A, making only a watt of power, or 1/9th of what the panel is capable of. Still, it managed to make my 115 Ah deep cycle battery slowly climb in voltage.
Since I used 32 cells instead of 36 (due to my glass size), I was worried that overcast days would result in no charge, but those worries appear to be unfounded. These second rate cells perform much better than the manufacturer’s rating and at 99 cents per 10 of them, you can’t go wrong.
In case you are interested in building a panel similar to mine, I purchased my cells from this ebay store: http://stores.ebay.com/ecoworthy2011
Here’s the update I promised on my solar panel. As I mentioned in my last post, I have figured out a dirt cheap way to build them. By using metal from a old computer case for the frame and finding free glass, you can build solar panels for cheap or even get paid to build them.
What do I mean by getting paid to build them? It isn’t too hard to get a free computer. Ask a few friends and family, watch the street corners on trash pickup day, and you’ll get a computer or two. By scrapping out the components, you can pay for the solar cells, tabbing wire, and silicone you need to build the panel. Check your local scrapyards. You’d be amazed at how much money you can get from computer components. Take the time to separate everything out and you’ll get a surprising amount of cash. This is free energy at its finest and you are recycling to boot.
Here’s a picture of the completed panel facing upward with an hour of daylight left:
As you can see from the picture, holes are drilled along the sides to allow the panel to be mounted. The glass is held to the frame with clear silicone adhesive.
I need to build a tracking platform to mount the panel on to maximize output. Even with the sun low on the horizon, you can tell better efficiency can be had when you face the sun:
You can really tell from that angle this is not a professionally made panel, but it is working great for a first build. I hope this gives you some ideas on building your own panels. If you play your cards right, the panels will put money in your pocket and give you free energy during daylight hours. This is real free energy that can be yours today.
For many reasons, solar is not the best alternative energy source out there. Solar cells are expensive, not very efficient, and the sun doesn’t shine all day are some of the big ones. That being said, a basic solar energy system is easy to put together and simply works when the sun shines.
To offset the cost of solar panels, I decided to build my own from second rate cells ordered from ebay. To my delight, the cells all performed better than the specification the manufacturer had stated. Here’s a picture of me testing it before I finish mounting everything:
With the panel straight up and the sun in the morning phase, it managed to pump .3 Amps into the battery quite nicely. It could put a good charge into a motorcycle battery and run a 2 Watt fan simultaneously. So for under $4, it is looking like a winner. Better numbers will be had when it is completed and can actually face directly into the sun.
I’ll continue posting my progress as this project comes together. I’ve got a few tricks up my sleeve that make panel construction cheap and allows more energy to be harvested from the sun.