I would have liked to set up a PV system large enough to meet all of my household needs, but I quickly learned that a system of that size costs more than I was prepared to spend. Instead of saving money and waiting, I decided to start off small and add to the system over time.
While there are some advantages to building a big system all at once, there are also advantages to starting small. When an ice storm knocked out power to my home for a week, I was glad to have the modest amount of power my small system provided. If the idea of starting small appeals to you, here are two strategies you might consider:
The least expensive option consists of one or more solar panels, a charge controller, batteries, and an inverter. Such a system can be built for less than one thousand dollars. If your needs are limited to lighting, and perhaps a radio, TV and computer, this system might be just right. You can always add to the system later, and add a refrigerator, freezer, microwave oven, and other appliances to the load. You’ll have to keep an eye on the system, switching to another power source when your batteries are depleted. For backup power and battery charging when the sun doesn't shine, you might consider a small gasoline-powered generator.
Using an intelligent controller, you can build a system that runs your household on battery power until the battery voltage drops to a set point. At that time another source of power takes over. This source of power can be a generator, or the utility grid. If you rarely experience grid power outages, the utility grid might be your best option. If utility-supplied power is unreliable, you might choose a generator instead. Automatic switching between power sources is possible. The beauty of this system is that it uses all of the power your system can generate before switching to more costly power sources. None of the PV-generated power is wasted. As you add solar panels, your savings increase accordingly. Because of the sophisticated equipment required, this option is significantly more expensive than the first one.
At some point in the not-to-distant future I believe that the demand for solar panels and equipment will skyrocket. To avoid supply-and-demand cost increases, I chose to install a small system rather than to wait until I could afford a larger one. I’ve benefited from this system in many ways, and haven’t regretted my decision.
Happy New Year!