Here on our off-grid homestead, we use PV panels as part of our energy solution. PV takes the energy in the sun’s light, and converts it directly to DC electricity for battery charging. A inverter then takes the low voltage DC, and converts it to 120vac house current. In other countries, it may be converted to 220vac. The number of PV panels you need is determined by your electrical usage, and the part of the world you live in. We get 2.5 full sun hours a day, another area might get 6, so they would need fewer panels than we do for the same load. A good beginner’s tutorial can be found here . It’s a PDF, and requires Adobe Acrobat.