Currently, I have 21, fifteen watt panels. The choice, in part, is because those high wattage panels work best in near full sunlight. With the type of solar voltaic panels I'm using, they produce an overall lower output, compared to the most current technology but, with this older solar technology I am still able to develop about 3 amperes of charge current, even on a pretty cloudy day.
Another thing is, if I lose a panel or two, I still have the bulk of my solar array to keep charging the battery bank - all of my eggs aren't in one or two baskets, but 21 baskets.
And lastly, I simply could not afford something like $500.00 a shot for the high wattage panels. Money rules!
Even with the lower wattage solar panels, Iíve spent a small fortune on deep cycle marine batteries, a Xantrex Pro-Watt 2000 watt true sine-wave inverter, wire, etc.
I had to get a true sine-wave inverter because my pellet stove would not run with a conventional square wave or modified wave inverter.
Then there was the Xantrex C60 charge controller and automatic transfer switch, also made by Xantrex
The deep cycle marine batteries are Xide 12 volt, 100 ampere hour rated.
The 1/0 wire is custom cut and terminated by PowerWerx.com. The 200 ampere fuse holders, 200 ampere fuses, 175 ampere and 50 ampere Anderson power pole quick disconnects were also purchased from Powerwerx.com.
The pellet stove will run continuously for about 9 days on the fully charged 600 ampere hour battery bank.
My goal was to put in more energy than Iím taking out, when running the pellet stove. And as of today, I am at that point. In the summer, with some management, I will be able to run the refrigerator an freezer for an hour or two per day, keeping them at temperature. They are in a cool area in the basement so the temperature differential is much lower than if upstairs in the heat of summer.
The thing about designing and building a solar voltaic generator is that, everyoneís energy requirements will vary. I started this project as an experiment several years ago and it sort of snowballed into something I had no intention of spending so much money on. But one thing led to another, and I suddenly had the beginnings of a system that could be made to work over time, and Iím still working on it.
My system has some shortcomings, to be sure, but every solar voltaic power generator design will dictate choices, sacrifice and limitations. Nothing is free, no matter what the book worms say. And Iíve read plenty of books on solar voltaic generation. The most prohibitive aspect of this endeavor was cost. If I had about $30,000.00, I would have done everything totally different, as I'm sure most of us have to do. My real advantage is that I have an degree in electronics and about 50 years experience in electronics both, as a hobby and professionally. So, I have a clear advantage with making technical decisions that many people attempting doing this type thing donít have.
I will get away with less power generation because of knowledge of exactly how the system performs and management that many individuals canít do because they donít have the ability to reasonably design in the data collection and management automation.
I am at a point now where I want to start working on designing LED lighting into some existing light fixtures, further reducing my energy usage.
The only real advice I can give is, calculate your expected energy requirements and double it. Be willing and understanding of the fact that you will not get all you want or need out of any solar voltaic power generator. That is, do you have lighting tonight, or do you spend that energy on using your computer for some worthy purpose today. Do you listen to the shortwave radio tonight, or do your use the Jig-saw and power drill to fix the chicken coop today. The fact is, if you plan on having electric power in a grid down situation, you will necessarily need to alter your lifestyle to ensure that the most important energy requirements continue to be met.
I chose a solar voltaic power generator over a petro-fueles power generator for stealth and for the fact that I believe gasoline and Diesel will not only become scarce in a grid down situation, but impossibly expensive. With fiat currency turned to barter, you would more than likely have to give up valuable assets for that scarce fuel. Once set up, a solar voltaic power generator will provide 10 years or more of limited energy with no additional investment, other than some basic maintenance.
So anyway, as I said, your energy needs will more than likely be substantially different than my energy needs. You have to plan and design your system according to your perception of what will be a realistic energy requirement for you.
One last comment is in order hereÖ I currently have a 600 ampere hour battery bank that that I hope to expand to 900 ampere hours over the next few months. At 600 ampere hours, the amount of available uncontrolled energy equates to 7.2 kilo-watts of direct current energy. At 900 ampere hours the potential uncontrolled energy of the battery bank comes to 10.8 kilo-watts of DC energy. If you do nothing else, make sure you understand the dangers of what you are working with and make absolutely sure you learn and employ safety practices relevant to the dangers you face with such a large DC energy source. Use proper fusing. Use proper wiring sizes and wiring practices. And for sure, use proper safety equipment when servicing the system like a face shield, a rubber apron and rubber gloves. This kind of stuff has serious dangers that you need to be constantly mindful of, when designing, building, operating and maintaining it.
I hope this helps.