I will add that you can get a 45 watt (3) panel solar system at Harbor Freight company on sale now for $199
But make one sounds fun too

Thats 0.062 KW it probably runs for about 360 hours a month on average (12 hours of day light a day) that means it makes 22.32 kWh at a constent rate. At 23.3 cence a Kwh over a year this solar panel generates $62.41 dollars a year of energy. This means at $100 your looking at 19.3 month pay back.

If it lasted 10 years over 10 years you would save $523.72 per panel or $52.4 a year per panel over 10 years

Lets say you live somewhere cloudy it only works half the time at worse thats still a 38.6 month or just over 3 year pay back. If it lasted 10 years over 10 years you would save $423.35 or $42.3 a year per panel over 10 years

I put in a big system, about 10,000 watts and it was right about $70,000… the panels were about $56,000 of that.
Just to make the numbers easy, lets say I spent a total of $7/watt and the panel was $5.5/watt.
The remaining $1.5/watt was for inverters and installation.

Mike built his 60 Watt panel for roughly $120 (again, guessing for plexiglass, caulking, etc) or $2/watt. Figure either way you need inverters and such, let’s figure if you scaled this up you could do 10,000 watts for $3.50 ($2 + $1.50) per watt or a total of $35,000.

Cool… doing it yourself could save you $35,000… not too bad.

But… once my system was installed, inspected, and operational, I was eligible for $3/watt credit from the power company or $30,000, a $1000 state income tax credit, and a 30% federal tax credit ($70,000 * 30% equals about $21,000)

So… $70,000 – $30,000 – $21,000 – $1,000 equals roughly $18,000… and my system is connected into my house electrical panel and helps to run everything whenever the sun is out which in my area is the most expensive power. I don’t have to worry about a battery bank and the maintenance and dangers that go with that.

Mike did his because he doesn’t have the grid available and I think it’s wonderful. As he says, he’s using it to charge batteries and things so he doesn’t need inverters, power company approval, or big banks of batteries… a very efficient and effective use of solar power. But, for peope who want to scale up to making enough power to actually run a significant portion of their house, a commercial, licensed install can actually end up cheaper.

I welcome questions about this and will answer as time permits. Please feel free to write me at yumadome@yahoo.com

“This is for 108 5×6 cells we cut from larger cells[all cells are cut from something] we have resealed the cut edge with a high temp. electrical epoxy, these are factory detabs the tabbing was removed in the factory by hot air some solder has been blown around and there are some very small spots on some of the cells, that is easy to remove, these are easy to use the cell is pre tinned by the factory tabbing process, these are 6.7 AMP THATS RIGHT 6.7AMP .5V these are 16% eff. thats .226AMP per sq. inch. you can not buy the low power 3×6 cells this cheap, THIS IS THE REAL THING.”

So each cell is (5″)x(6″)=30 sq.” Each cell produces (30sq.”)x(.226A)=6.78A. 6.78A x .5v = 3.39 watt (IxE=P). 108 x 3.39W = 366.12W total power. 108 x 30 sq.” = 3240 sq. in. 144 sq. in. = 1 sq. ft. 3240 sq. in. = 22.5 sq. ft.

We can see from the above that our assembled panel will cover 22.5 sq. ft. and produce 366.12 Watts. The solar cells are 16% efficient which is pretty good. 366.12watts/22.5sq.ft=16.272 watts/sq. ft. In full sun, you can safely assume about 100 watts of solar energy per square foot. If this panel was 100% efficient we would expect to produce about 100 watts but we are producing 16.2 watts…so it is 16% efficient.

If we assume 6 hours/day of full sun to allow for cloudy days and seasonal changes we will produce 366.12 watt x 6/hr. = 2196.72 watt (2.197 KW)/day. I live in North Carolina and I pay $0.12/KWH, which is the national average, so…$0.12/kwh x 2.197kw = $0.26364/day. This panel would produce about 25 cents worth of electricity per day for me if I used it directly as a direct current source (DC). If I stored it in a battery for later use I would only be able to recover about 80% ($0.26x.8=$0.20), or 20 cents. If I recover the energy using an inverter to convert to 120v AC it would be considerable less due to the inherent losses.

The 108 cells were advertised at $150.00 + $17.44 = $167.44 (cost + shipping). The payback would then be $167.44 / 0.26/day = 635.108481262 days (1.740023236 years = 1yr,9mo.). If I add in the cost of building the frame…lets say it all comes to a total of $300.00 then the payback becomes $300 / .26364/day = 1138 days (3.12 years = 3yr,1.5mo.). Not too bad expecially if their was any rebates available from local, state or federal.

According to the US Department of Energy, an average American household used approximately 866-kilowatt hours per month in 1999 costing them $70.68. Now it would be $104.00./mo.

For anyone interested David Butcher has a design for a human pedal powered generator that can produce about 300 watts per hour of exercise, which if added to this solar powered setup would double the amount of energy produced. http://www.los-gatos.ca.us/davidbu/pedgen.html

@Brendon, where did you get the idea the author was your own personal slave? Grow a braincell and then learn how to think for yourself already.

Why is it that braindead morons always try to ruin it for everybody else?

To the author: Thanks for the write-up and the inspiration. I plan to use some of the ideas you portrayed here.

Being independent from the system has a lot of value in itself. I am 100% off grid, I generate all of my own power and store it in batteries, I didn’t break the bank to get here, I can tell you from experience how good it feels when the power goes out in the neighborhood and I’m not even aware of it.

With the aging utility infrastructure, more and more people getting on the grid, we are just one hot summer, one extra cold winter blizzard/ice storm, one hurricane away from major power outages. Being energy independent, even on a small scale (ie your house), is priceless.

But it’s ok with me if you want to sit back and spout ROI numbers as an excuse/reason not to get off the grid, or at least have some sort of backup system, those of us who look at life though a different lens will be sitting in our lit up houses while you will end up sitting in the dark, hope your numbers keep you warm and bright. :)

Wretha