Photovoltaic (PV) solar power uses solar cells to convert sunlight directly into electricity, which is either used immediately or stored in batteries for future use as required. In RV applications, the electricity generated by the solar panels is collected by a charge controller and transferred to 6 or 12 volt deep cycle batteries. Battery power is then used to operate DC (direct current) equipment such as interior lights and water pumps. The addition of an inverter would allow use of some 120V appliances such as microwaves, coffee makers and surround sound entertainment systems.
Solar electric systems are modular, which means one can start with a small system and add to it as requirements grow. They are ideal for operating low power items, such as blenders, microwaves, coffee makers, radios, lamps, stereos and computers. However, due to the very high power demands, appliances which produce heat or are used for cooking and storing food (stove, fridge, furnace) are generally not powered by solar.
Flat plate solar panels can make use of both direct light and indirect light (sunlight reflected off clouds, the ground or other objects) and southeast to southwest is the prime solar location. With no moving parts, the solar panels can last 20-30 years with proper maintenance, which includes cleaning with a damp cloth to remove dust, insects, leaves, bird droppings and/or snow, and repositioned twice a year (spring and fall) unless they have been installed at an angle that provides best average for different seasons. The panels can be placed on roofs, ground mounted or attached to a pole, as long as they are immersed in full sunlight on the south facing side.
Though the individual photovoltaic cells are solid-state devices with no moving parts and therefore highly reliable and long lived, the modules they are placed into are subject to failure, as is the remainder of the system. The failure of solar cells mostly involves cell cracking, interconnect failures (resulting in open circuits or short circuits), and increased contact resistance. Module-level failures include glass breakage, electrical insulation breakdown, and various types of encapsulant failures.
Read more about the basic components of a solar system and sizing solar systems (pdf).