Some people may not know what off-the-grid or off-grid means, so here it is --- The term off-the-grid or off-grid refers to living in a self-sufficient manner without reliance on one or more public utilities.

Off-grid living is no longer a one room log cabin in the woods. It's energy independency. You don't have to rely on utility companies, you create your own power. Today, there are more than 180,000 off-grid homes in the US.

Sunday, June 14, 2015

Solar Power...

12:28 pm - 76 degrees - sunny...

Most off-grid homes use a wide range of energy resources, in sharp contrast to the typical all-electric suburban home.  One energy resource that we are using is solar power.

Solar power is produced by collecting sunlight and converting it into electricity.  This is done by using solar panels.  Solar panels are large flat panels that are made up of many individual solar cells.  Lots of small solar cells spread over a large area that work together to provide enough power to be useful.  The more light that hits a cell, the more electricity it produces.

photo source: alternate energy info

Once you have assessed your solar power needs and the amount of solar gain you can expect, the next step is figuring out where and how to mount your solar panels to get optimum light exposure.  There are a numerous ways to mount solar panels, and the best choice depends not only on maximizing exposure over the course of a year, but also cost and practicality.  Depending on city or county code requirements, that can sometimes mean thousands of dollars in engineering and equipment.  When all is said and done, simplicity is key.

Two important things to keep in mind when you’re looking at where to place your solar panels are which direction the solar panels should face and the optimal angle the solar panels should be tilted.

Where to place your solar panels - in general there’s one big rule: if you’re in the U.S. (or anywhere else in the Northern Hemisphere), your solar panels should face true south (aka solar south or geographic south).

Identifying true south is not as simple as using a compass.  Due to the imperfections in the composition of the earth, due south rarely matches the compass reading.  A compass points toward the south pole of the earth’s geomagnetic field.  It’s the right general direction – but not exact.  

A simple method to finding true south is to look at your house on Google Earth; after centering the image on your home, you can view the north-south grid lines Google provides.  In the View menu, select “Grid”. 

Another easy way to identify true south is to look in your local newspaper (or Google) for the exact time of sunrise and sunset for that day.  Calculate the middle of these times; it should be somewhere near noon, but rarely right at noon.  Stick a pole in the ground, and at the exact middle time between sunrise and sunset, the shadow from the pole lines up with due south.

Once you have the direction the solar panels should face, next comes finding the optimal angle the solar panels should be tilted to get the best out of your system.  

The optimum angle varies throughout the year, depending on the seasons and your location.  Of course, the sun is continually moving throughout the day and to get the best from your solar panels you would need to angle your panels to track the sun minute by minute.  You can buy an automated solar tracker to do this but unfortunately, the expense of a tracker means that for most systems they are more expensive than buying additional panels to compensate.  The amount of power a solar tracker uses in order to track the sun also negates much of its benefits.

The sun is at its highest at solar noon each day (this occurs exactly half way between sunrise and sunset) and by using a Solar Angle Calculator {Click Here} you can find out the angle at that time of day.  At solar noon, the irradiance from the sun is at its very highest and you can generate the most power.  In the northern hemisphere, the sun is due south at solar noon.

photo source: gogreensolar.com

If you want to get the best performance during the summer months, you would angle your solar panels according to the height of the sun in the sky during these months.  If you want to improve your winter performance, you would angle your solar panels towards the winter months in order to get the best performance at that time of year.  If you have the opportunity to adjust your solar panels throughout the year, you will benefit from having the optimum angle on a month by month basis.

After all that has been said, here is what we did – simplicity is key after all. 

We picked up 8 solar panels that are roughly 2’6” x 5’6” for free.  We know nothing about them other than they were for a 12 volt system.  Free is a very hard price to pass up especially when to buy them new would be a minimum of $1,600.

Not knowing anything about the panels and how well they would perform, we didn’t want to spend a lot of money on a mounting system.  So Tony came up with a design using scrap materials that we had lying around the house.




This simple design allows them to be moved around on the forks of a tractor if we deiced we want to place them in a different location.


The orchard crates will be partially filled with large stones found around the property to counter weight the solar panels and anchor them down for high winds.



This simple design also allows the solar panels to be adjusted for optimum positioning in any direction and angle. 



They are facing due south and still need to be tilted to the proper angle for this time of year and are easily adjustable for the winter months.  Just after 7:00 pm last night the panels were producing 19.2 volts to 19.5 volts each.


We're half way done.  Need to build two more racks and then onto the wiring.


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