Even though I’m not one of those “go green – save the earth” types, this link pretty much explains what motivated me to explore building a first solar panel. Based upon what was learned depending on solar panels for our electric needs would be economically impractical.

Next time you’re looking at one of those “google ads” implying you can get free electricity by building a $200 solar panel to power your house and sell electricity back to the electric company keep the following in mind: Some things you can believe while some should be taken with a grain of salt, others with a block and still others with the entire salt mine. Just as there is no free lunch there likewise is no free electricity.

From what I’ve seen “going green” is about getting the green from my pocket more than exercising conscientious stewardship over the environment. The last electric bill I saw represented 33 days during the last part of November and first part of December 2009. Some of the coldest weather of the year was during that time and we use electric heat. Per day average was 77.5 KWH. Some days exceeded that and others were less but for the sake of this let’s stick with 77.5 KWH/day. A solar array with 23 panels, each producing 144 watts 24 hours/day would yield 79.488 KWH/day. Of course that would require sunlight around the clock so let’s figure winter time 5 hours light per day at 144 watts/hr and we’ll need 108 panels to get 77.76 KWH/day. Of course that is assuming sufficient light for panels to produce the full 144 watts 5 hours each day. Nice concept but not necessarily realistic. Figuring each panel costs about $250 to build 108 panels comes to $27000.

Solar panels sometimes function 20 years or longer. Commercial panels often carry a 10 year guarantee. Assuming 10 years with $27000 initial cost would come to $225/month just for the panels. Every year beyond that would be bonus bucks. Then again we need to add costs for array structure(s) to mount panels, battery bank(s) that probably won’t last 10 years, charge controller(s), power inverter(s) and various and sundry wires and connectors, not to mention efficiency losses. Then there is personal time and effort researching, designing, building and organizing everything. Yep, it all adds up.

Economics may not be the reason for building a solar electric system but there are a couple good reasons that encourage me to keep building. Aside from temporary outages due to storms, floods, earthquakes and other natural causes let us not discount the possibilities of terrorist actions, governmental intrusion or even total economic collapse. No, I’m not predicting anything but don’t discount the possibilities. In all of these circumstances I prefer to have a source of electricity that requires no commercially produced fuel. Gasoline, diesel, LP and natural gas could be too expensive or difficult (perhaps even impossible) to obtain.

Because sitting in the dark wishing I had prepared sounds highly undesirable, the next phase begins.



Each of the 36 cells produces .5 volt and 3.5 amps or 1.75 watts in bright light. So let’s do a little math here:
At .5 volt X 36 cells connected in series you get 18 volts which is considered good for charging a 12 volt battery (or bank of batteries). In other words: .5v X 36 = 18v

At 18 volts X 3.5 amps you get 63 watts. In other words: 18v X 3.5amps = 63 watts

Connected in series? Think of a flashlight that uses three C batteries. Each battery goes in the same way meaning the positive post of one battery is in contact with the negative post of the next. With three 1.5 volt C batteries placed that way there is a total of 4.5 volts to the bulb. If you have a flashlight that uses only two batteries it is 3 volts. If you have one that uses 4 batteries it is 6 volts. It’s the same when putting solar cells together – positive to negative and by chaining all 36 cells positive to negative there will be 18 volts in bright light.

There is a bit more than just connecting a solar panel to a battery or bank of batteries. There’s a chance of over charging, using more electricity from the battery than the panel can provide or even discharging the battery when low light causes reverse flow of electricity from battery back into the solar panel. Reverse flow can be prevented with diodes which prevent current flow from battery to solar panel. It is not a method I would use with other than very low power solar panels.

Solar charge controllers are designed to prevent battery overcharge, battery discharge beyond a preset level (usually 10.5 to 11.5 volts) and reverse discharge. Charge controllers vary from less than 5 amps to high amperage. For the sake of the storage shed experiment I’m looking at a $23, (shipping included) 15 amp charge controller from an eBay seller.
Project progress so far is limited to solar cells ($70), personal knowledge and experience (hopefully to prove of value), charge controller @ $23 if that’s the one I buy, various and sundry materials to mount cells into a panel (jury is out on that expense so far), power inverter (oh yeah, haven’t mentioned that yet), 12V battery (may just be a battery borrowed from a camping trailer for now) and who knows how many bits and pieces from the neighborhood hardware store. Yep, you’re seeing it as I do: this ain’t exactly what ya call free electricity. Then again, everything has it’s price.
The plan was to post this last evening (Thursday) but experience dictates not to publish to the blog when staying awake is a major problem. This morning (Friday) rolls around and while catching up on emails the doorbell rings. Amazing: USPS with a package addressed to me. Sure enough, solar cells!

Part three coming soon.

Other projects captured my interest and I thought nothing more of it until two days ago when I happened upon a link that took me to that very same site. Well that got me questioning how logical it would be to buy that information, build the “under $200” wind powered generator and use it to provide some part of our electric use. So I did a bit of rough calculating.

Information download: $50

Wind generator: $200

Wow, shouldn’t take much time at all to pay for itself. That is until you dig into the FAQs. You see the unit is built with the “goal” of generating 500 watts at winds of 20 MPH or above. Um, I’m here in North Dakota, on the plains, we get quite a lot of wind but I can guarantee we seldom see 20 MPH sustained winds. But OK, for the sake of this let’s just say we have 500 watts generated 24 hours per day. In the course of a month (30 days) that would mean 360 kilowatts. At a current per KWH rate of $.05/KWH there would be an $18 per month saving from my electric bill.

Sounds good so far don’t it? With higher output unit we could supply all we need for the house and even sell the excess back to the electric company. But there’s that 20 MPH wind to consider. Let’s get closer to realistic and say we have pretty consistent 10 MPH winds. Now we’re only generating 250 watts and maybe saving $9/month. Oh and did I mention the electricity generated is probably not 120 Volt 60 cycle alternating current so you’ll need to charge battery banks (not inexpensive) and use an inverter just so your appliances will work. Inverters are notoriously inefficient so after generating that 250 watts and charging the batteries you may end up getting 125 watts (I don’t know, possibly more or less) from that 500 watt generating system. If you decide to build a much higher capacity unit at much higher cost, the cost of charging equipment, expense for greater capacity battery bank(s) and the much larger inverter needed to supply larger amounts of electricity to your appliances adds up.

Of course the bottom line question is will it pay for itself? I sincerely believe it will but I also believe before that break even point you could have paid the electric company for a long time. You likewise will have repairs and maintenance above and beyond the initial costs and may need to pay qualified people to assure your system is properly connected.

Tempted though I may be, I think it’s not for me. I’m sure glad there are people out there willing to undertake these endeavors and I expect incredible advances are being made every day. I’m fascinated and that fascination will never go away.