Knowing your power needs will save you a lot of headaches and money, when you start “unpluging” (no pun intended) from the grid. Solar photo voltaic systems are pretty expensive, so reducing the demand and energy requirements will make a big difference in your pocket.
Harnessing solar energy to power your home is a great way to cut energy costs. To get your solar power system right, you have to spend time planning to determine how much energy you need to generate. The following is a great resource to simplify the process when going off the grid. Read it here "The Essentials of Planning Your Solar Power System"
"Most off-grid houses use a wide range of energy resources, in sharp contrast to the typical all-electric suburban home. Solar hot water heaters are always good candidates because they're cheaper per kilowatt-hour than an off-grid photovoltaic system, and solar lighting systems are always wise. This variety can be an advantage in that you aren't completely disabled by power blackouts. In fact, you'll be completely impervious to power outages, and even if one of your resources goes down, the majority of your lifestyle will still be intact.
Off-grid solar electrical systems all use the same basic components, with other elements added according to need.
Here are the main functions you need to consider when going off the grid
The charge controller feeds current into the battery bank at the required voltage. Good charge controllers draw the best performance out of the batteries and are very important for economics because they influence efficiency.
The battery bank is typically made up of six or more individual batteries connected with stout cables in either series or parallel arrangements.
The inverter changes DC to AC voltages suitable for use with household equipment. An inverter is optional if you use DC loads exclusively.
DC loads controller
You may be using both DC (boat, RV, and auto appliances) and AC loads (standard household appliances). The DC loads controller maintains the proper currents and voltages into the DC loads.
As a backup power supply, the AC generator isn't strictly necessary but is usually part of any off-grid system in order to prevent blackouts when the sun is weak for extended periods.
The transfer switch alternates the power source between either the inverter output (when battery power is available) or the AC generator.
AC loads controller
This device includes appropriate fuses and switching means and maintains the voltages and currents used by the AC appliances connected to the system."
"You don't need to go off-grid with your entire home. You'll save on your power bill, plus enjoy some interesting independence and help save the environment, all in one.
Taking your reading lamp off the grid
If you like to read, you can spend $50 to get a small, battery-charged light (LED) that works for four hours on a four-hour charge. A PV module with a length of wire attaches to a battery/light/switch housing with Velcro backing. Apply the matching Velcro anywhere you may want light. During the day, plug in the PV module and set that in the direct sunlight. At night, press the light into the Velcro and use it.
Installing solar light tubes (tubular skylights)
A solar tube lighting system collects sunlight on the roof and transmits it down a shiny silver pipe into the diffuser, which broadcasts the light into the room below. Solar light varies with the clouds and weather, changing the intensity of light in the room quite a bit. You're much more conscious of the outdoors. When the sky is partly cloudy, you can get a lot of fluctuation.
Using solar fans
Simply take a small 12VDC room fan and a suitable PV panel and wire them directly together. The hotter the sun, the more the air moves; no need for batteries. At $150, a solar fan isn't a cheap option, but it may be reasonable if your energy costs are high enough. Plus, you can use one anywhere; you don't need a plug.
Read our post How to Make Solar Panels for Your Small Electronics for a step by step simple off the grid ways to power you small electronics.