Homesteading and Livestock
Self-reliance and sustainability in the 21st century.
Living Off Grid: Our Solar Power System
3/16/2012 12:54:45 PM
By Ed Essex
Tags: off grid, living off grid, solar power, solar, Ed Essex
Solar Power has come a long way in the past decade or so. We are living proof of that, after all, what did we know about solar power or even electricity for that matter? Yet here we are in our second full season, living off the grid with solar power. Systems today are so sophisticated they run by themselves and the only thing you really have to worry about is battery maintenance if you have a battery storage system as part of your package.
While I am sitting here telling you that modern solar power systems are relatively hands free, I don’t recommend that you operate them that way. I believe you should get as involved in your system as you can. For me, that meant there was a lot to learn and it has taken some time to do so.
PanelsMy system consists of 8 each 215 watt REC panels on a fixed position steel pole. The panels were recalled by REC, rebuilt and put back on the market at a discounted price. My inverter is a Xantrex XW 4024 with an automatic generator start control module. My charge controller is an Apollo T-80 HV. I also have 12 each Solar One 2Volt batteries for a 24 volt system. My backup generator is a propane fueled 12,000 watt Kohler Residential outdoor unit. I bought this unit knowing Kohler wouldn’t warranty it for off grid use.
The system capacities are as follows;
Panels - 1720 Watts
Inverter – 4000 watts
Battery Storage – 1160 Amp Hours or 22 Kwh Storage which means about 3 days for us because we don’t like our batteries to go below 60% capacity. (I actually don’t usually let them go below a 30 percent discharge or 70 percent capacity).
Inside the house we have a Trimetric Reader that allows us to see what our electrical usage is at all times and what state our battery capacity is at. It also helps to track how long it has been since our batteries were charged to 100% and how long it has been since we equalized our batteries which for me has to occur once a month.
Our system will run our house, barn and 220V water pump for two people easily. When the sun shines it produces more power than we need. The only reason we have the backup generator is because the sun doesn’t always shine. You could have as many panels or as much battery storage as you want. No sun, no power. We use our backup generator about 100 hours per year.
Total cost of this system was about $22,000. The current Federal tax code allows for a 30% credit so we only ended up paying $15,400 for our system. Our panels are warranted for 25 years and the batteries should go at least 10 and up to 15 years.
If there was an electrical source for power at the edge of our property it would have cost between $14,000 to $19,000 just to get the power from the road to our house and then you would have a monthly power bill on top of that.
So in our situation it cost the same amount whether we brought in power or installed solar power and with solar, there will be no monthly bills. The decision to go solar was easy.
Power SystemAs I mentioned earlier, these systems are almost hands free if you want it to be that way. You can program your inverter to “run” the operation with no input or help from you. The only thing you would have to do is maintain your batteries.
In our case, with our preferences, the inverter would do the following:
Allow the panels to charge the batteries to 100 percent. Once they reach 100 percent the inverter switches the charge controller off except for just enough power to keep the batteries tweaked at 100 percent. If there is no sun, the batteries will discharge to 60 percent capacity at which time the inverter will turn the generator on automatically, charge the batteries back up to 100 percent and then turn it off again.
That’s the simplest explanation I can give you about how sophisticated this equipment is now. It could manage the whole charge/discharge/ charge process if you wanted it to without you ever lifting a finger.
I don’t allow my system to do everything automatically. I keep my panels tilted in the most advantageous angle. I start and stop my generator by hand. By doing that and watching the weather reports pretty close I can squeeze a few more amps out of my system for less time on the generator. It also helps me to keep an eye on things like battery temperature, water levels and equalization. I also decide when my water pump goes on. It is set up on a float system and would pump automatically but if I see that we can reach 100 percent battery capacity first and then pump water because we are going to have sun for a few days I may delay the pumping until it’s the perfect timing for my battery condition. All of this participation results in you becoming more aware of your electrical use and that ultimately results in less power used.
As stated earlier my system totaled about $22,000. I had other quotes ranging from the same price with different equipment (different design), to $37,000 and $45,000. That’s a big difference. It pays to shop. We had this system installed for us. If you live in Washington State or Idaho and would like to talk to the licensed person we used you can reach me through either website listed below and I will be happy to put you in touch with him