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******Shameless Self-Promotion******
Most of what I write isn't relevant to Instructables. My main blog is here: biodieselhauling.blogspot.com
**End Digression... On to the Good Stuff**
Most solar systems installed on houses are hooked up to a special electric meter which can both draw on the grid and feed back into it - which makes the meter run backward.
That is pretty cool!
However, these systems generally run from around $25,000 to $50,000 and take anywhere from 10 to 20 years to make up for their up front cost in reduced utility bills.
My solar photovoltic system is independent of the utility company. It cost me about $400 (unless you happen to live in an RV, boat, or cabin, it will cost you just a little bit more)
I still use traditional electricity for some things, so I still get a bill each month, but it reduced my electric bill by almost $15 a month, which means it will pay for itself in a little over two years.
Most of what I write isn't relevant to Instructables. My main blog is here: biodieselhauling.blogspot.com
**End Digression... On to the Good Stuff**
Most solar systems installed on houses are hooked up to a special electric meter which can both draw on the grid and feed back into it - which makes the meter run backward.
That is pretty cool!
However, these systems generally run from around $25,000 to $50,000 and take anywhere from 10 to 20 years to make up for their up front cost in reduced utility bills.
My solar photovoltic system is independent of the utility company. It cost me about $400 (unless you happen to live in an RV, boat, or cabin, it will cost you just a little bit more)
I still use traditional electricity for some things, so I still get a bill each month, but it reduced my electric bill by almost $15 a month, which means it will pay for itself in a little over two years.
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Signing UpStep 1Reduce demand
The first step for any type of solar system is to find ways to dramatically reduce the power you use in the first place.
My previous instructable is a great place to start: http://www.instructables.com/id/Not-your-average-save-energy-advice
These are steps you should be thinking about doing anyway, but it becomes all the more important when doing a solar electric project.
This is because solar systems (whether grid-intertie or not) are priced by the kilowatt. The fewer you need, the less your system costs, and the sooner it pays for itself.
My previous instructable is a great place to start: http://www.instructables.com/id/Not-your-average-save-energy-advice
These are steps you should be thinking about doing anyway, but it becomes all the more important when doing a solar electric project.
This is because solar systems (whether grid-intertie or not) are priced by the kilowatt. The fewer you need, the less your system costs, and the sooner it pays for itself.
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vandejake
Just found a good source this morning, Platt Electric is selling the 225 watt SolarWorld Sunmodule series panel for $374.22 each (or about $1.66 per watt).
These panels run at 29 volts nominally though, so you would need a charge control system that can regulate the voltage.
Even so, $375 for a 225 watt panel is a great deal, and I would encourage anyone who could use a panel of that size (and voltage) to take advantage of it.
Thanks for the tip.
I have corrected the 'ible
Of course, nearly all of the components of a computer use DC, with the converter/charge controller built into the AC power supply. (The display on a laptop contains an inverter to go back to AC - how much is wasted by that???) If that step could be eliminated, you could add your 'puter to the list.
Somewhere in my searching I came across DC plugs, male and female, that look very much like AC versions and can be installed just like household wiring, eliminating the "cigarette lighter" version. If I can find a link, I'll post it later.
All in all, you've provided great information clearly explained and tied together. Bravo!
As it happens, I spent about 20 minutes yesterday looking at different options for running my computer on 12V yesterday.
I have a laptop - which uses less power than a desktop; problem is that they need more than 12v. Mine runs on 18v. So a straight 12v cord won't work.
I found a few converters for under $4, but I'm concerned about their quality and safety features (or, rather, lack there of).
There are some for around $20 that look good, and I'll probably end up getting one.
http://www.backwoodssolar.com/catalog/electrical.htm#DC%20SWITCHES%20&%20OUTLETS
I admire and respect independent folk, but as a more urban-oriented type I'm looking for community solutions; think neighborhood or city block solar power stations rather than the extremes we have now --massive generation-transmission systems or self-contained pioneers like yourself. Any thoughts?
If you custom built your own DC application (like with a computer power supply) you could use any regular 120v 20amp outlet and it would work fine.
As to community level solar - in a way that is what grid-intertie systems are now, since they feed back into the neighborhood electric supply. I suppose if there were enough of them in a given area, its hypothetically possible that they could keep the block going in a power outage (assuming the mains were disconnected beyond the block)
Never really thought about that before.
Anyway, while I like the compliment, I am not really self-contained (nor a pioneer!), I live in the city and am still connected to the grid. I just tried to find a small scale compromise between the traditional way and going full solar.
I am thinking of an inverted design where the panel is upside down over a parabolic trough, with a cheap bladder full of oil on the back. As the oil in contact with the back of the panel heats, it will rise up, causing convection currents within the oil. Might knock up a prototype.
As Jacob says, a reflector is usually cheaper than another panel.
For example, I have 5 hours of usable light on average. But the sun is up for about 12 hours each day. More than half of those hours aren't maximized because the angle of the sun is too low to capture the light. Having a reflector wouldn't necessarily help during the peak daylight hours when the sun is already hitting the panel directly, but it would capture some of the incidental light at other times, increasing the total watt hours the panel produced over the course of the day.
The more I think about it, the more I think I'd like to try it
I guess you could make the reflector 'wider' and you would extend the hours as you say above Jacob. And if you made it 'deeper' you would extend the wattage - although there is a relationship between the two.
http://www.youtube.com/user/miscbeep#p/u/21/hmrAynAQPf4
http://www.youtube.com/user/miscbeep#p/u/29/YZYau6GXUm4
I am keen to try the oil cooling idea....
I have been looking at ideas for simple solar concentration methods and have noticed some people are starting to put a square of reflective material on the ground in front of the panel as set up in Step 8. This causes more incidental light to reflect and hit the panel, upping the wattage.
I am about to do some experiments at home to see if it helps me make more power for my solar greenhouse.
http://samdidgaf.blogspot.com/search/label/Hothouse
The reflector idea would definitely help out for a green house (or solar hot water heater, passive solar heating, solar refrigeration, or anywhere else where you want to concentrate heat as well as light)
The problem with using a reflector in a PV (photovoltaic) panel application is that they are powered by visible light, not by heat, and a reflector can cause excess heat to build up on the surface of the panel, and the hotter the panel gets, the less electricity it produces (and the less long it lasts).
Although, it might not be a bad idea in the winter time, when temperatures are cooler and there is less available sunlight for power.
I'll have to look into that
This is true, however you are still limited by the wattage of the solar panel. In most cases, the amount of surface area used by a mirror would be better utilized by placing another solar panel in its place as this will increase the system wattage as a whole.
In other words, a 200 watt panel can indeed generate more than 200 watts if there is more than 1000 watts per square meter.