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Our Simple DIY Home Solar Power System

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This basic off-grid solar power system is simple to install and can be easily expanded…

By Greg Seaman, Posted Jul 18, 2012

DIY Home Solar power systemBringing some of the benefits of electrical power to our off-grid home has been a hit-or-miss affair. Over the years we’ve tried some very simple approaches to lighting and small battery recharging for our flashlights, such as hauling a 12 volt car battery to a small rural school about a half mile away every time it needed to be topped up. This was time consuming and inefficient. But we didn’t want to lose the feel of our simple home by bringing in a large generator and the jugs of gas needed to run it, and the prospect of setting up a wind turbine or solar array seemed expensive and a technological eyesore in a natural setting.

…developing using a dialup internet connection on a phone line strung through the woods was challenging…

For many years we managed to get along without the conveniences which electricity can provide, but developing using a dialup internet connection on a phone line strung through the woods was challenging, and charging my laptop became a regular necessity. A few years ago, wireless broadband was introduced to our area, and the promise of high-speed internet was the stimulus we needed to build our own reliable, affordable and simple “do-it-yourself” alternative energy system.

Today, with the help of a local expert on off grid home solar power and alternative energy systems, we have the best of both worlds. Our basic solar powered energy system provides more electricity than we expected, it has been very reliable and maintenance-free, and it is almost entirely hidden from view. A solar panel on the roof with a few wires leading to a small battery bank powers my laptop, and a radio mounted on a tree for receiving the wireless broadband signal. The system also provides enough energy to charge several small power tools, run our home sound system and, amazingly, power a full-size chest refrigerator year round.
solar battery bank
Our simple home solar power system is comprised of four basic components: a solar panel, a charge controller, two 6-volt golf cart batteries and a small inverter. My son and I were able to install the system in a few hours, and there have been no maintenance issues other than checking the fluid level in the batteries every few months. The cost of this complete solar system, in today’s pricing for the components, was less than $1000.

The cost of this complete solar system, in today’s pricing for the components, was less than $1000.

We have already enjoyed about three years of trouble-free use from this system. The refrigerator has not been off for over two years, which is pretty impressive considering we live in the Pacific Northwest where the short winter daylight hours provide minimal solar exposure for the panel.

The basic components of this off grid solar power system are as follows:

1. Solar panel

We have a single solar panel mounted on the roof of our home: a 123 watt Sharp Photovoltaic Module, model 123UJF. The panel is equipped with a permanently attached junction box for ease of installation of wires and conduit. Two boards are lag screwed into the roof and the solar panel is bolted to the boards using wing nuts, so it’s easy to lift if maintenance is required. The panel surface is about 5” above the roof surface. The panel is hinged to the mounting board, which allows the panel to be tilted towards the sun, and to increase ventilation. We plan on adding a cog/string system to make it easier to tilt the solar panel towards the sun from the ground. Two wires run from the solar panel, one is the power line and the other is a ground line. The power line runs down the roof to the charge controller, where there is a fuse. A box on the porch which houses the charge controller, inverter and batteries. The ground wire runs beneath the house and is attached to a rod which is driven about two feet into the earth.
solar panel
It should be noted that the panel guidelines state that the installation of PV modules requires a “great degree of skill and should only be performed by qualified licensed professionals, including licensed contractors and licensed electricians.” We installed our system ourselves because our supplier, who is a licensed installer, gave us explicit directions and came by to inspect the installation after it was done. We suggest that you follow the recommendation as stated in the module instructions with regard to installation.

You may notice there is a shadow on the panel being installed in the picture above. This shadow crosses the panel in about 20 minutes, so there is a small loss of efficiency over the course of a day. But we live in a beautiful forested area and I value the tress more than 100% efficiency in solar gain. If there were a major solar loss I might top the tree, but our system provides for our needs and so we will live with the shadow, for now at least.

The cost of the solar panel in today’s pricing is about $425.

2. Charge Controller

We use a Trace C12 Charge Controller which automatically adjusts the amount of power running into the battery. The controller has a small LED light which indicates the state of charge so it’s easy to see when the batteries are fully charged or if they are becoming depleted. The light flashes either red or green, with multiple flashes indicating the status of charge at any given time. We can see that if the light is red we should reduce our power use, and if the light is green then we have the power needed to charge or run additional devices.

charge controller

The cost of the Trace Charge Controller is about $90.

3. Battery Bank

Two 6-volt golf cart batteries are wired in series for a 12 volt system. Each battery is rated at 232 amp hours. The batteries are enclosed in a wooden chest with hinged lid, and the top panel of the chest is removed to provide plenty of ventilation. The battery posts and connections are kept clean, and periodically checked to ensure good connections.
solar batteries
battery box
The cost for the two batteries was about $400.

4. Inverter

The final piece of the system is a small inverter which converts the 12 volt DC power into 120 volt AC power. This enables us to use standard electric devices without the need for adaptors. Inverters are available in a wide range of wattages for different size systems. Ours is a small inverter made by Nexxtech, rated at 300 watts, with a 500 watt surge capacity. It comes with two cables, red and black, with alligator clip ends for gripping to the battery posts. In choosing which size inverter to buy, we calculated how much power was available to our system and what devices we wanted to run. In calculating power needs, it is important to add the power requirements when two or more devices are running simultaneously.
solar inverter
Our Nexxtech 300 watt inverter cost about $30.

What this system provides:

An alternative energy system can be used to provide electric power to any number of electric devices, such as appliances, tools and computers. The bigger the system, obviously, the more power it will provide. To give you an idea of the capacity of a small system like ours, here is what we use our solar energy system to power:

solar powered refrigerator
This is a DC powered refrigerator, the same size as a conventional chest freezer (4’ wide). The refrigerator draws 40 watts of power and can be converted to a freezer by replacing the thermostat. Since the refrigerator is a DC model, it is wired directly to the battery, bypassing the inverter. So the refrigerator keeps running even if the inverter is turned off. Our refrigerator has been running continuously for over 2 years without any problems. Even during the dark days of winter, the unit has adequate power to keep running.

vers sound systemThis is our Vers sound system which lets us use an iPod or direct cable from an iPhone or computer to deliver a rich sound while drawing relatively little power. We can run this sound system about 3 hours a day in winter, and as much as we want in summer.

solar powered laptopOur solar system provides adequate power to run a laptop computer all day if necessary. We also run a router from our inverter so that multiple computers can be operated at the same time. In addition to the router, a small radio is installed on a tree about 300’ from our house which receives the wireless broadband and transmits the signal to the house.

Besides the laptop, we have a battery-powered driver-drill, which is a very useful tool. Our system recharges the battery for this tool in about 30 minutes.

These are the principle applications we use which are provided by the solar power system described above. However, you can use a wide variety of electric devices as needed. Today, we enjoy the benefits of our system without feeling a technological intrusion into our off-grid homestead and lifestyle. The refrigerator especially has made a big improvement in our day to day living, since storing food is so much easier. Over time we may expand our system by adding more batteries for storage, and eventually a second solar panel or small wind turbine.

Bringing electricity to rural locations is something of a balancing act since we don’t want our simple lifestyle changed by too many electrical gadgets. It does require some restraint to keep things simple, but the few electric amenities we now have are most appreciated!
GregAbout Greg
Originally from Long Island, NY, Greg Seaman founded Eartheasy in 2000 out of concern for the environment and a desire to help others live more sustainably. As Editor, Greg combines his upbringing in the cities of New York, Boston and San Francisco with the contrast of 31 years of living ‘off-grid’ to give us a balanced perspective on sustainable living. Greg spends his free time gardening, working on his home and building a wooden sailboat with hand tools.


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  • Greg Seaman

    Your comment seems so familiar. You’ll do fine and will enjoy your energy independence. We’ve had great results from our Sundanzer fridge, which is easy to convert to a freezer. Very low wattage, runs off a single 127 watt panel, has been running steady for over 4 years. This is a full size chest unit.

  • Francisco Turalba

    This is perfect for my needs GREG. Thanks. I am from from the Philippines where we have more than enough sunshine and heat! Airconditioners are a must!

    Greg , I wonder if you can advise me on how and what kind of set up I need to install to run two or three split type AC’s. Two horse power per AC. That’s on top of the rest of my power needs like light, ref, power tools & PC’s. We don’t have TV. In short I want to be totally off grid.

    Thanks again GREG. You are a blessing to mankind! :) if I can do this I am sure I can convince my friends to have one installed in their homes. Business oppurtunity for us Greg?

    • Greg Seaman

      Hi Francisco,
      Thanks for your comments. The costs and options for solar arrays, inverters and charge controllers keeps dropping, and I am not an expert on recommending systems. You’ll get better advice from your local solar provider who will know what options are available in your area, as well as the ideal configurations. You just need to bring them a list of your energy needs.
      Yes, there are certainly business opportunities in this field – renewable energy is ready for wide use in the general population.

  • greener1122

    This approach is very workable and what I developed is similar, utilizing one large panel, deep cycle batteries, inverters, a charge controller and the peripherals that allow everything to be hooked together and inserted on or within a snug battery box.There is about 2000 watts output which will indeed power up most household appliances (except air conditioning and electric heaters–such as a garage door opener, skil saw, medium sized fridge, coffee pot, any electronics, vacuum cleaner etc.–for hours if not days, depending on location and draw.

  • Greg Seaman

    In our location we have no electric power.

  • Greg Seaman

    Thank you Onye for your kind comments. It is very gratifying to me.
    Saludos to you!

  • Onye Onye

    Hi Greg. Thanks for getting back. You know what, I am thinking of collaborating with Eartheasy once i get back to Nigeria next two yrs to start developing individual power unit completely independent of the National Grid. It is a shame that in Nigeria, there is frequent blackout inspite of the windfall from crude oil, large water bodies which can be damed, or even generate power from Gas that is been flared to the atmosphere in the refineries. Your solar set-up is the simplest available in the web. to testify to that , u can see the huge interest and post on it, over 100. Its simplest is quite encouraging. By the way, I am an agric engineer and u know that solar energy utilization in engineering or agric has the sky as its limits.of water. I am getting back to u in future meanwhile i enjoy reading the posts. Hasta luego señor.

  • Greg Seaman

    Yes, it is getting to where independent power systems are viable for small applications like homes and small communities. The prices have been steadily going down and the technology continues to improve.
    Thanks for your comments.

  • Greg Seaman

    Calculate all your anticipated electric needs and take the list to a solar power dealer or an alternate energy provider. They should give you a free estimate of what your system requirements will need to be.
    For the refrigerator, read our blog about solar refrigerators. Our suggestion is to go with a chest style, DC powered, with easily replaceable thermostats. Thay way you can convert it to a freezer when needed. We use the Sundanzer model 225.

  • Greg Seaman

    Your local solar installer should be able to give you a free consultation.

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